Thông tin tài liệu
COGNITIVE STYLES AND 2D:4D FINGER DIGIT RATIO IN ASIAN
MALES: PERFORMANCE ON VISUOSPATIAL JUDGEMENT AND
FACIAL EMOTION RECOGNITION REACTION TIMED TASKS
TAY KAY CHAI
B.A. (PSYCHOLOGY & LINGUISTICS), UNIVERSITY OF MELBOURNE
A THESIS SUBMITTED
FOR THE DEGREE OF MASTER OF SOCIAL SCIENCES
DEPARTMENT OF PSYCHOLOGY
NATIONAL UNIVERSITY OF SINGAPORE
2011
Acknowledgements
I am especially grateful to my supervisor, Dr Simon L. Collinson for his valuable guidance
and constructive criticism. This thesis would not be possible without his continuous
supervision and expertise from pre-study planning till the end of my thesis write up.
I would also like to express my heartfelt gratitude to my fabulous family and friends.
They have been supportive throughout the entire process. Some provided valuable
feedback for my thesis from a layman point of view. Others gave me encouragement of
sorts. Mostly importantly, they have all been there for me at one point or another.
Finally, the research study would not be possible without the volunteers who agreed to
participant and completed all the interviews and experiments.
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Table of Contents
Page
Acknowledgements..............................................................................................................ii
Table of Contents ................................................................................................................iii
Thesis Summary ..................................................................................................................iv
List of Figures ......................................................................................................................vi
Chapter 1
1.1
1.2
1.3
Cognitive styles: Systemizing and empathizing ................................................... 3
Sex hormones ..................................................................................................... 11
Study aims and hypotheses................................................................................ 18
Chapter 2
2.1
2.2
Results ......................................................................................................... 28
Characteristics of the sample ............................................................................. 28
Cognitive styles (systemizing/empathizing) and cognition................................ 30
2D:4D finger digit ratio and cognition................................................................ 41
Summary of findings .......................................................................................... 44
Chapter 4
4.1
4.2
4.3
4.4
Methods ...................................................................................................... 20
Participants......................................................................................................... 20
Measures and experimental tools ..................................................................... 20
Chapter 3
3.1
3.2
3.3
3.4
Introduction .................................................................................................. 1
Discussion.................................................................................................... 47
Cognitive styles (systemizing/empathizing) and cognition................................ 48
2D:4D finger digit ratio and cognition................................................................ 51
Limitations and future directions ....................................................................... 52
General conclusion ............................................................................................. 54
References ........................................................................................................................ 56
Appendix A ........................................................................................................................ 62
Appendix B ........................................................................................................................ 70
Appendix C ........................................................................................................................ 71
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Thesis Summary
The cognitive style ‘systemizing’ describes an individual’s proclivity to understand rules
and systems while ‘empathizing’ describes an individual’s motivation to identify and
respond appropriately to others’ emotions and thoughts (Baron-Cohen, 2003). The
second to fourth (2D:4D) finger digit ratio is indicative of the level of prenatal
testosterone (Brown, Hines, Fane, & Breedlove, 2002; Manning, Bundred, Newton, &
Flanagan, 2003). Both these factors have been shown to be sexually dimorphic in the
area of spatial and social cognition. However, extant studies demonstrate an
overemphasis on clinical population; little information pertaining to the comparison
between spatial and social cognitive performance; show inconsistent findings for
functional asymmetry in spatial and social cognition; and have a lack of investigation on
the speed of processing in spatial and social cognition. The present study adopted the
spatial cognitive task – Spatial Categorization/Coordinate task of Kosslyn and colleagues
(1989) and derived a novel social cognitive task – Facial Emotion Recognition task, that
mirrors the presentation of the spatial task to examine the cognitive performance in the
two hemispheres in a group of Asian men, based on their cognitive styles and 2D:4D
finger digit ratio. The results indicated that cognitive style is predictive of facial emotion
recognition and spatial categorization task but not for spatial coordinate task. No
association was observed between the 2D:4D finger digit ratio with both the spatial and
social cognitive tasks. On the other hand, the effect of functional asymmetry was
observed for all the tasks. Apart from supporting the notion that the left and right
iv
hemispheric biases for verbal and spatial cognitive abilities respectively is
oversimplified, the current study demonstrated some evidence for the precedence of
functional asymmetry over cognitive styles and 2D:4D finger digit ratio for both spatial
and social cognition.
v
List of Figures
Page
Figure 1. The left and right visual field and the pathways leading to the right and left
hemispheres of the visual cortex (Kimura, 2000, p. 140). ............................... 23
Figure 2. Obtaining the measurement for the second and fourth finger digit lengths. ... 27
Figure 3. Accuracy and reaction time between the two systemizing groups for stimuli
presented in the right visual field (RVF)/left hemisphere (LH) and the left
visual field (LVF)/right hemisphere (RH). ......................................................... 32
Figure 4. Accuracy between the two empathizing groups for stimuli presented in the
right visual field (RVF)/left hemisphere (LH) and the left visual field
(LVF)/right hemisphere (RH). ........................................................................... 33
Figure 5. Reaction time between the two empathizing groups for stimuli presented
in the right visual field (RVF)/left hemisphere (LH) and the left visual field
(LVF)/right hemisphere (RH). ........................................................................... 34
Figure 6. Reaction time between the two empathizing groups for stimuli presented
in the right visual field (RVF)/left hemisphere (LH) and the left visual field
(LVF)/right hemisphere (RH). ........................................................................... 35
Figure 7. Accuracy between the two systemizing groups for ‘happy’ male facial
emotion presented in the right visual field (RVF)/left hemisphere (LH) and
the left visual field (LVF)/right hemisphere (RH). ............................................ 36
Figure 8. Accuracy between the two systemizing groups for ‘angry’ female facial
emotion presented in the right visual field (RVF)/left hemisphere (LH) and
the left visual field (LVF)/right hemisphere (RH). ............................................ 37
Figure 9. Mean reaction time between the two empathizing groups for ‘angry’
female facial emotion presented in the right visual field (RVF)/left
hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH). .......... 38
Figure 10. Accuracy and reaction time between the two empathizing groups for ‘sad’
male facial emotion presented in the right visual field (RVF)/left
hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH). .......... 39
Figure 11. Accuracy between the two empathizing groups for ‘sad’ female facial
emotion presented in the right visual field (RVF)/left hemisphere (LH) and
the left visual field (LVF)/right hemisphere (RH). ............................................ 40
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Figure 12. Reaction time between the two empathizing groups for ‘fearful’ female
facial emotion presented in the right visual field (RVF)/left hemisphere
(LH) and the left visual field (LVF)/right hemisphere (RH). .............................. 41
Figure 13. Reaction time between the ‘masculine’ and ‘feminine’ groups for stimuli
presented in the right visual field (RVF)/left hemisphere (LH) and the left
visual field (LVF)/right hemisphere (RH). ......................................................... 43
Figure 14. Reaction time between the ‘masculine’ and ‘feminine’ groups for stimuli
presented in the right visual field (RVF)/left hemisphere (LH) and the left
visual field (LVF)/right hemisphere (RH). ......................................................... 44
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Chapter 1
Introduction
Sexual dimorphism is a concept which describes the morphological, behavioral and
functional phenotypic variations between the sexes in a species. Sexual dimorphism is
observed across both humans and other animals. Among humans, obvious
morphological variations between the sexes such as height (Hines, 2005) and brain size
(Hines, 2005) with men being taller and having greater brain volumes compared to
women.
Scientists have observed sexual dimorphism in a number of domains including
interpersonal interaction, academic ability, psychomotor ability and cognition (BaronCohen, 2003; Hamilton, 2009; Kimura, 2000). Generally, these studies have shown that
men demonstrate better performance in mathematics, generate more complex systems
of classification, obtain higher scores on the mathematics component of the Scholastic
Aptitude Test and perform better in the interception of balls. Conversely, women
generally show superior abilities in verbal memory, memory of objects’ location in an
array and the recognition of facial emotions. In human cognitive psychology, visual
spatial tasks possibly demonstrates one of the biggest sex differences with male
advantage particularly for the mental rotation task and spatial perception skills (Hyde,
2005; Voyer, Voyer, & Bryden, 1995). On the other hand, a meta-analytic study confirm
that facial emotion processing demonstrate female advantage (McClure, 2000). In
1
addition, this observation is possibly related to brain structural differences between
male and female (Gur, Gunning-Dixon, Bilker, & Gur, 2002).
Evolutionary psychologists postulate that sexual dimorphism in human cognition is
consequential of our evolutionary origins. Particular to spatial cognition, men tend to
adopt a “bird’s eye” view of the topography while women remember landmark details
better due to the evolutionary pressures of long distance travelling by men in search of
food and mates, while women are postulated to have paid attention to nearby children
and foraged within a small area (Dabbs Jr & Chang, 1998). Similarly, men’s enhanced
performance of the mental rotation task has been attributed to their role in tool making
(Kimura, 2000). With respect to social cognition, women scored better than men on
measures of empathy considering that ancestral women were more involved as
caregivers, and women predominantly made use of relational aggression while men
tend to use physical aggression (Loon, 2009). Albeit the myriad of sexual dimorphic
attributes described in cognition literature, some evidence suggest that such sex
differences might be exaggerated (Hyde, 2005) and the magnitude of such differences
reduced over time (Voyer, et al., 1995).
Sexual dimorphism in cognitive performance has prompted scientists to explore the
potential underlying factors in greater depth. Two important factors arose from studies
looking at sexual dimorphism – Cognitive styles (Baron-Cohen, 2003) and 2D:4D finger
digit length. In addition, sexual dimorphism for functional asymmetry is commonly
2
observed (Hines, 2005; Kimura, 2000). These factors will be expounded in separate
sections below.
1.1
Cognitive styles: Systemizing and empathizing
In order to explain sexual dimorphism in the occurrence of autism where every one
female who has autism is matched by four males with this condition, Baron-Cohen
(2003) proposed a theory which encompasses two different styles of thinking or
‘cognitive styles’ namely systemizing and empathizing. Systemizing is defined as “the
drive to analyze, explore and construct a system. The systemizer intuitively figures out
how things work, or extracts the underlying rules that govern the behavior of a system”
(Baron-Cohen, 2003, p. 3) while empathizing is “the drive to identify another person’s
emotions and thoughts, and to respond to them with an appropriate emotion” (BaronCohen, 2003, p. 2). Systemizers typically display aptitude in figuring out how things
work, or rules governing the behavior of a system. In contrast, empathizers are generally
able to detect others’ emotional nuances and react accordingly.
Cognitive styles in the current context should not be confused with the same term that
cognitive psychologists traditionally conceptualized as the way someone perceives and
remember information along a dimension (Kozhevnikov, 2007). While the two definition
might share similar or overlapping characteristics, Baron-Cohen’s (Baron-Cohen, 2003)
conceptualization of cognitive style is born out of the volume of work with autistic
3
children and endeavors to explain functional and cognitive differences between
individuals with and without autistic traits. In addition, systemizing and empathizing are
treated as relatively independent cognitive styles. The two cognitive styles are elicited
by two independent 60-item questionnaires. As such, an individual can score equally
high or low for both cognitive styles.
The prevalence for autism, a condition marked by repetitive behavior/obsessive
interests and, deficiency in social development and communication (APA, 1994; ICD-10,
1994), is skewed towards males (Skuse, 2000). An extension of systemizing cognitive
style, the “extreme male brain”, is exemplified by autistic savants, who are cognitively
and socially inept individuals but nonetheless display superhuman feats in a specific
domain. The domains of interest which are typical of savants including mathematics, art,
music and linguistics may be considered as abilities that require systemizing thinking.
Specifically, autistic savants were observed to possess hypersensitivity to details and
extraordinary ability to extract concrete rules and relationship that can be applied
consistently within a single domain (Baron-Cohen, Ashwin, Ashwin, Tavassoli, &
Chakrabarti, 2009; Hermelin, 2001). These observations correspond to Baron-Cohen’s
(Baron-Cohen, 2003) definition of systemizing. Similar to sex bias in autism, autistic
savant males outnumber females (Treffert, 2009).
Baron-Cohen (2003) extend his theory of cognitive styles to include males and females
in the general population where men are predominantly systemizers and women
4
empathizers. According to Baron-Cohen (2003), the notion that cognitive style is
sexually dimorphic is corroborated by behavioral and cognitive evidence observed
among neonates through to adults. Additionally, the theory attributes biological
precursors for sexually dimorphic brains based on the observations that sex typical
behaviors come about at a young age (Baron-Cohen, 2003, p. 91) and are observed
across many diverse cultures (Baron-Cohen, 2003, p. 93).
For example, at birth, girls looked longer at faces while boys looked longer at suspended
mechanical mobiles (Connellan, Baron-Cohen, Wheelwright, Batki, & Ahluwalia, 2000).
similarly, sex based proclivity for certain objects has also been observed in vervet
monkeys where young males showed preference for a car and a ball; young females
showed preference for a doll and a pot; while no difference in preference was observed
for a picture book and a stuffed dog, items that have not previously been showed to
result in a differential preference between human boys and girls (Alexander & Hines,
2002). In the same vein, occupations that are essentially systemizing such as the crafting
of musical instruments, physics and mathematics are predominantly occupied by men,
while women tend to favor empathizing occupations like nursing, therapy and teaching
(Baron-Cohen, 2003; Kanazawa & Vandermassen, 2005).
Apart from autism, other clinical studies that revealed sexual dimorphism include the
observation that men who suffer from schizophrenia demonstrated lower premorbid
and current functioning compared to women (Häfner, 2002; Salem & Kring, 1998;
5
Shtasel, Gur, Gallacher, Heimberg, & Gur, 1992). Similarly, social functioning were
previously attributed to superior premorbid functioning and social skills among women
in a group of schizophrenic and schizoaffective patients (Mueser, Bellack, Morrison, &
Wixted, 1990).
In the cognitive domain, men and women display varying aptitudes such as the mental
rotation task, the embedded figure test, verbal fluency and emotion recognition (BaronCohen, 2003). Men generally perform better on spatial tasks while women perform
better on tasks involving facial emotions (Baron-Cohen, 2003; Hamilton, 2009; Kimura,
2000). In at least one study, men who obtained higher scores on systemizing than
women, also performed better on the mental rotation task and a targeting task
compared to women (Cook & Saucier, 2010).
Baron-Cohen (2003) places emphasis on biological differences in the brain between the
sexes. While this notion is supported by the evidence aforementioned, the concept of
systemizing-empathizing cognitive styles is essentially a measure of the outcome of a
combination of biological and sociocultural factors because it examines an individual’s
level of systemizing and empathizing at the point when s/he response to the
questionnaire (Appendix A). The resultant cognitive style is therefore viewed as a
combination of biological and social influences over the course of the person’s life
rather than biological antecedents per se. Baron-Cohen concedes that while biology
plays a part in shaping cognitive styles, culture and socialization are indisputable factors
6
that also contribute to sexually dimorphic brains (Baron-Cohen, 2003). In fact, social
factors are identified as essential in contributing to sexual dimorphic behaviors in
differential predilection for science and mathematics between men and women
(Halpern et al., 2007) and inferring other people’s thoughts (Thomas & Maio, 2008). This
notion is similar to a study which examined the concept of psychological gender (Bourne
& Maxwell, 2010). This study found that the psychological male showed greater
lateralization for the recognition of facial emotions. Specifically, psychologically
feminine males showed greater right hemispheric bias for the anger, sadness and
surprise emotions. This is analogous to the notion that males with empathizing cognitive
style show the same hemispheric bias for these facial emotions.
To date, research on cognitive styles (Baron-Cohen, 2003) is skewed towards the clinical
population, predominantly autistic children. Much less is known about cognitive styles
among the healthy population. While few studies found male and female superiority for
systemizing and empathizing respectively in the healthy population (E.g. Baron-Cohen,
Richler, Bisarya, Gurunathan, & Wheelwright, 2003; Connellan, et al., 2000;
Wakabayashi, Baron-Cohen, & Wheelwright, 2006), extant studies are generally skewed
towards the clinical population.
Similarly, research on cognitive styles (Baron-Cohen, 2003) emphasizes between-sex
differences. Researchers concede that there are certainly overlaps between the sexes
(Baron-Cohen, et al., 2003; Kimura, 2000). In other words, it is possible for some men to
7
show cognitive profile similar to women and vice versa. Information regarding the
variability of cognitive styles within the sexes remains scant. This notion is further
investigated by Hyde (2005) who proposed the Gender Similarity Hypothesis in reaction
to the overemphasis of between-sex differences in the literature. In particular, while
there is little argument against physiological differences and associated motor
performances between the sexes, sexual dimorphism in the cognitive domain is more
contentious (Hyde, 2005). Of particular interest is the 118 studies mentioned in Hyde’s
(2005) review which examined facial expression processing found effect sizes ranging
from -0.13 to -0.92. A subsequent study noted that genes are also contributing to
individual differences in cognitive styles including empathy (Knafo, Zahn-Waxler, Van
Hulle, Robinson, & Rhee, 2008). Apart from inconsistency among findings for sexual
dimorphism, observable differences within the same sex are also reported previously.
Such within-sex behavioral differences are noted when other variables such as race
(Ostrow, Hammer, Renard, & Knight, 1997), sexual orientation (Kimura, 2000) and
sociocultural gender roles i.e. modern vs. traditional feminine gender roles (Lindstrøm,
1999) are considered.
Extant studies report either spatial cognition or social cognition while seldom
concurrently examined both spatial and social cognition (Baron-Cohen, 2003; Hines,
2005; Kimura, 2000). Additionally, these studies generally examined the performance of
the subjects in terms of accuracy while it remains unclear if an individual’s cognitive
style influences the processing time. Examining the speed of processing is important
8
considering that slower speed of processing could be a tradeoff for increased accuracy.
Generally, studies which examined cognitive performance between the cognitive styles
either did not make comparisons between spatial and social cognitive performance (e.g.
Knickmeyer, Baron-Cohen, Raggatt, Taylor, & Hackett, 2006), use spatial and social tasks
that are very different (e.g. Cook & Saucier, 2010), and/or did not consider the speed of
processing in the cognitive tasks (e.g. Connellan, et al., 2000; Cook & Saucier, 2010).
Taken together, the task format for the current study is similar for both spatial and
social tasks with regards to stimuli display length and respond time.
Baron-Cohen (2003, pp. 105-111) also draws parallels between cognitive styles and
functional asymmetry. The two hemispheres of the brain display structural and
functional asymmetry. Functional asymmetry refers to the notion that the left
hemisphere is predominantly “described as analytic or concerned with sequential
processing, whereas the right is considered to be concerned with the integration of
information over space and time, a holistic or gestalt processor” (Bryden, 1982, p. 2). An
example of structural asymmetry is the wider right frontal region compared to the left
and a wider left occipital region compared to the right (Geschwind & Levitsky, 1968;
Weinberger, Luchins, Morihisa, & Wyatt, 1982). Functionally, lesion studies have
revealed that patients with lesion on either of the two hemispheres reported spatial
neglect for the contralateral visual fields (Ringman, Saver, Woolson, Clarke, & Adams,
2004; Vuilleumier & Rafal, 2000).
9
The notion of functional asymmetry has been criticized by scholars in response to the
public’s misinterpretation of brain specialization and spurious claims relating to brain
type training (Goswami, 2006). For instance, advising teachers to adopt left and right
brain balanced instruction has no sound scientific basis (Goswami, 2006). However,
functional asymmetry that is observed in narrowly defined, limited types of cognitive
processes remains valid for further exploration. This is evident in the modularity
approach in understanding cognition including but not limited to language production.
For instance, the Wada test, involving the administration of sodium amytal into the
blood stream to essentially put to sleep either of the hemispheres revealed greater
involvement of the left hemisphere in language processing (Milner, 1975; Rasmussen &
Milner, 1977). Similarly, Baron-Cohen (2003) has argued that baby girls showed greater
amount of electrical activity in the left hemisphere compared to the right hemisphere
when exposed to sounds of speech. Among adults, greater lateralization for language
occurs in men more so than women (Baron-Cohen, 2003). Considering evidence as such,
Baron-Cohen (2003) inferred that greater systemizing ability is related to greater right
hemisphere function. For example, professions which rely heavily on spatial cognition
like architects and visual artists tend to be right hemisphere dominant based on the
observation that more of them are left handed compared to other professions.
However, this conjecture has not been verified empirically and the current study aims to
fill this gap.
10
Admittedly, recent evidence suggests that a top-bottom (dorsal-ventral) differentiation
might be a better representation of cognitive processes compared to left-right
differentiation (Borst, Thompson, & Kosslyn, 2011). Particularly, it is notable that this
representation is governed by the distinction between cognitive processing that is either
“expectation-driven” (top/dorsal) or “classification-driven” (bottom/ventral) (Borst, et
al., 2011, p. 630). In other words, expectation-driven processing essentially involves
preexisting knowledge while classification-driven processing refers to the identification
of stimuli at a superficial, perceptual level. However, a discussion on intelligence and
neural network mentioned that even classification of stimuli on a perceptual level could
involve higher level influence (Hawkins & Blakeslee, 2004). Taking all into consideration,
the experiments in the present study are constructed as classification-driven tasks that
tap on perceptual cognitive processing. Additionally, functional asymmetry is examined
as an exploratory factor rather than a predisposing variable in cognition.
1.2
Sex hormones
Androgen and estrogen constitute the two broad classes of sex hormones. Their
respective masculinizing and feminizing effects are observed both physiologically
(Nelson & Luciana, 2001, p. 60), behaviorally (Nelson & Luciana, 2001, p. 61) and
cognitively (Kimura, 2000, p. 179).
11
Studies of individuals with sex hormone abnormalities have revealed insights about the
effects of sex hormones on human cognition and the importance of sex hormones for
brain
development.
For
example,
males
with
Idiopathic
Hypogonadtrophic
Hypogonadism or Androgen Insensitivity, a condition where there is deficiency in
testosterone, have been shown to demonstrate poorer performance in spatial tasks
compared to healthy males (Kimura, 2000, p. 179). Females who are born with
Congenital Adrenal Hyperplasia, a condition resulting in aberrantly high levels of
androgens, show enhanced ability in spatial tasks compared to their healthy sisters or
close female relatives (Kimura, 2000, p. 109). Similar observations are also observed in
the healthy population (Kimura, 2000, p. 179): both men and women demonstrate
disparity in their spatial ability based on their testosterone levels, and changes in sex
hormones are related to congruent changes in cognitive performance.
Developmentally, there are three activational periods when testosterone level peaks –
first, during the prenatal period; second, around five months following birth; and finally,
during puberty (Baron-Cohen, 2003, p. 98). Prenatal and postnatal testosterone is
thought to have organizing effects and activating effects respectively (Geen, 2001).
Distinct from the transient activating effects of postnatal testosterone, organizing
effects of prenatal testosterone have a long lasting influence on the brain’s
development and the concomitant cognition thereafter. Indeed, there is evidence
demonstrating that prenatal testosterone enhances the development of the right
hemisphere and concurrently slows down the growth of the left hemisphere (Geake,
12
2006; Grimshaw, Bryden, & Finegan, 1995; Sholl & Kim, 1990; Toga & Thompson, 2003).
It is postulated that the resultant brain structure leads to differential cognitive abilities
such as enhanced spatial ability in targeting tasks (Hines et al., 2003) and greater
specialization to the right hemisphere in recognizing emotions (Grimshaw, et al., 1995).
Putatively, the second to fourth (2D:4D) finger digit ratio is indicative of the level of
prenatal testosterone based on genetic research (Manning, Bundred, & Flanagan, 2002;
Manning, et al., 2003) and hormonal abnormality studies (Brown, et al., 2002; Manning,
et al., 2003). Specifically, lower 2D:4D finger digit ratio is associated with higher level of
prenatal testosterone and low CAG repeats. CAG repeats in the human genome located
on exon 1 codes for the amino acid glutamine and is also related to the expression of
androgen receptors (Cheng, Hong, Liao, & Tsai, 2006; Vermeersch, T'Sjoen, Kaufman,
Vincke, & Van Houtte, 2010). Among individuals with normal human genome, the
number of CAG repeats count from between 7 to 35. Low CAG repeats reflect higher
sensitively to androgen in vivo and vice versa. As such, phenotypic functionality and
physicality is indicative of CAG repeats. For instance, longer CAG repeats is related to
lower cognitive ability in measures such as visual reaction timed task among a group of
elderly Caucasian males (Yaffe et al., 2003). Evidence from hormonal abnormality
studies provide further support for the validity of 2D:4D finger digit ratio as indicative of
prenatal testosterone level. Females with Congenital Adrenal Hyperplasia were
observed to have lower 2D:4D finger digit ratio compared to healthy females (Brown, et
al., 2002). Similarly, males with the same condition have lower 2D:4D finger digit ratio
13
when compared to healthy males (Brown, et al., 2002). Conversely, at least one review
study conclude that 2D:4D finger digit ratio is not a reliable measure for many
characteristics, conjecturing that differentiation for finger digit lengths and prenatal
androgens take place at different times (Puts, McDaniel, Jordan, & Breedlove, 2008).
However, another meta-analytic study implied that controversies surrounding the
validity of the 2D:4D finger digit ratio exists but largely restricted to the relationship
between 2D:4D finger digit ratio and spatial cognitive abilities (Puts, et al., 2008). While
some evidence support the association between 2D:4D finger digit ratio and social
behavioral measures (e.g. Coyne, Manning, Ringer, & Bailey, 2007; Hampson, Ellis, &
Tenk, 2008; McIntyre et al., 2007), little is known about the relationship between 2D:4D
finger digit ratio and social cognition per se such as emotion stimuli processing. The
current study attempts to understand this inconsistency by examining this factor against
cognitive styles and their relative effects on both spatial and social cognition.
Furthermore, while 2D:4D finger digit ratio is not a completely reliable measure for
prenatal testosterone level, it is however, methodologically much easier to apply than
longitudinally measuring and testing using intrauterine measure.
Whilst some studies examining the association between 2D:4D finger digit ratio and
human cognition have reported a lack of significant associations (Coolican & Peters,
2003; Puts, et al., 2008), many studies have revealed congruent results (Putz, Gaulin,
Sporter, & McBurney, 2004). For example, it was found that lower 2D:4D finger digit
ratio i.e. higher prenatal testosterone level, was associated with better visuospatial
14
processing beyond sex effects (Collaer, Reimers, & Manning, 2007). In other words, both
men and women with lower 2D:4D finger digits showed better visuospatial task
performance compared to individuals with higher 2D:4D finger digit ratios. Among a
group of women, 2D:4D finger digit ratio mediated the performance in the ‘reading the
mind in the eyes’ task (van Honk et al., 2011). Administration of testosterone results in
poorer performance in the task among individuals who showed a masculine version of
the 2D:4D finger digit ratio.
In an experiment looking at the functional asymmetry for spatial and linguistic cognitive
process, Kosslyn and colleagues (1989) identified two types of spatial representations
that are processed by different hemispheres i.e. categorical specialization in the left
hemisphere and coordinate specialization in the right hemisphere. In the experiment,
the spatial categorical task require the participants to determine if a dot appears above
or below a line while the spatial coordinate task has the participants response to
whether the dot is close or far from the line. The spatial categorical task appears to tap
on the visual-spatial (dorsal system) while the coordinate task appears to tap more on
the visual-object processing (ventral system) as aforementioned. As such, opposite
pattern of responses for spatial categorical and spatial coordinate tasks should be
observed. Indeed, Kosslyn and colleagues (1989) found faster reaction times for the
categorical task and coordinate when the stimuli were displayed to the left and right
hemispheres respectively. Considering the role of 2D:4D finger digit ratio, better
performance in the spatial categorical task would be associated with higher 2D:4D finger
15
digit ratio while better performance in the spatial coordinate task would be associated
with lower 2D:4D finger digit ratio. This would be consistent with the notion that high
prenatal testosterone drives the growth of the right hemisphere, resulting in enhanced
spatial ability, which is concurrently a form of systemizing skill (Bourne & Gray, 2009;
Manning, 2002, p. 128). In addition, recent literature suggests that men are better on
categorical tasks (visual-spatial; dorsal stream) while women are better on the
coordinate tasks (visual-object; ventral stream) (Blazhenkova & Kozhevnikov, 2009).
Interestingly, the visual-object oriented tasks have been suggested to involved at least
to some extent an emotional system (Blazhenkova & Kozhevnikov, 2010).
Many studies have demonstrated the influence of sex hormones on social cognitive
abilities (e.g. Chapman et al., 2006; Hermans, Putman, & van Honk, 2006; Knickmeyer,
et al., 2006). For instance, subjects who were administered a dose of testosterone
subsequently showed lesser mimicry of facial expressions compared to those who were
administered placebo (Hermans, et al., 2006). Functional asymmetry is observed in
social cognition. Neuroimaging studies provide evidence which supports the left brain’s
role in emotion recognition. Specifically, greater left anterior amygdala activation
compared to the right was observed for rapid recognition of fearful and happy faces
(Breiter et al., 1996). While left activation for certain facial emotions is specific to certain
brain regions, the right hemisphere as a whole was associated with the recognition of
most facial emotions. For example, right hemisphere dominance and greater
lateralization for recognition of emotions in men was reported recently (Bourne &
16
Maxwell, 2010; Grimshaw, et al., 1995). An earlier study revealed that the right
hemisphere has specific advantage in processing negative emotions while the left
hemisphere processes positive emotions (Mandal, Asthana, & Biswal, 2008, p. 138). In
contrast, the activation of the right hemisphere was stronger in response to the
recognition of the happy side of chimeric facial stimuli, which was found to be related to
empathy among female subjects only (Rueckert & Naybar, 2008).
It was previously mentioned that behavioral studies pertaining to the effects of prenatal
sex hormones mainly examine clinical populations (Cohen-Bendahan, van de Beek, &
Berenbaum, 2005; Collinson et al., 2010; Gooding, Johnson, & Peterman, 2010). The
establishment of the validity of 2D:4D finger digit ratio has also been based on samples
drawn from population with hormonal disorders like Congenital Adrenal Hyperplasia
and Androgen Insensitivity. Additional evidence for the link between prenatal
testosterone level and 2D:4D finger digit ratio comes from a study on rats (Talarovicová,
Krsková, & Blazeková, 2009) and another that examined the amniotic fluid (Lutchmaya,
Baron-Cohen, Raggatt, Knickmeyer, & Manning, 2004). However, these studies did not
examine spatial and social cognition abilities.
While there are evidence associating 2D:4D finger digit ratio with spatial and social
cognition (Bourne & Gray, 2009; Putz, et al., 2004), no study has examined the
relationship of 2D:4D finger digit ratio to lateralized cognition in spatial and social tasks
that are similar in stimuli presentation. In addition, previous studies did not examine the
17
speed of processing for both spatial and social measures. Since it was previously
reported that 2D:4D finger digit ratio reflects growth of the right hemisphere (Geake,
2006), this may consequently mediate the accuracy and the speed of processing for
spatial and social cognitive tasks. Indeed, the study by Bourne and Gray (2009) found
that lower 2D:4D finger digit ratios were related to greater lateralization to the right
hemisphere for both the spatial and social tasks. However, they did not examine the
speed of processing for stimuli presented to the left and right hemispheres.
1.3
Study aims and hypotheses
The current study is an exploratory study aimed to examine the associations between
(1) cognitive styles with spatial and social cognition; (2) 2D:4D finger digit ratio with
spatial and social cognition.
Two issues in the extant literature are addressed in this study. The central issue the
current study sought to resolve is the inconsistent findings in the functional asymmetry
of visual-spatial performance and facial emotion recognition. The secondary issue to
resolve is the lack of studies which concurrently examine both spatial and social
cognition. In addition to administrating both types of cognitive tasks to the subjects,
qualitatively similar tasks were used to test these two types of cognition. A previous
spatial task (Kosslyn, et al., 1989) is used and a new social task that mirrors the
presentation of the spatial task is devised. For both the tasks, the accuracy and reaction
18
time among the groups is examined for each cognitive style (level of systemizing and
empathizing) and 2D:4D finger digit ratio category (masculine and feminine). Only male
subjects were recruited to obtain preliminary findings to examine the notion that
within-sex differences can be observed considering cognitive styles and 2D:4D finger
digit ratio.
19
Chapter 2
2.1
Methods
Participants
One hundred and five participants (all males) aged 19 to 34 years (M = 22.10, SD= 2.63)
were recruited for this study. Participants were undergraduates from the National
University of Singapore who took part in the study in fulfillment of course requirements
for introductory-level psychology courses and volunteers beyond the university. All
procedures were approved by the Institutional Review Board of the National University
of Singapore, and informed consent was obtained at the beginning of the study.
2.2
Measures and experimental tools
The tasks were administered in the same order for all participants. To minimize
distraction, participants performed the computer reaction timed tasks individually in a
quiet and darkened room. All participants were assessed to have normal or corrected to
normal vision. To prevent any diurnal effects on the cognitive experimental tasks, all
experiments took place in the afternoon between the hours of twelve to six.
Cognitive styles (SQ/EQ)
The SQ/EQ questionnaire (Baron-Cohen, 2003) was used to determine the degree of
systemizing and empathizing participants subscribed to. Each set of questionnaire
20
consisted of 60 items, of which 20 were filler items, measuring thinking traits on a 4point scale: 1=strongly agree, 2= slightly agree, 3 = slightly disagree and, 4=strongly
disagree (See Appendix A). The words motorways and subways were substituted with
expressway and MRT respectively to fit the Singapore context. For the SQ questionnaire,
the following items were scored two points for ‘strongly agree’ responses and one point
for ‘slightly agree’ responses: 1, 4, 5, 7, 13, 15, 19, 20, 25, 29, 30, 33, 34, 37, 41, 44, 48,
49, 53, 55. The following items were scored two points for ‘strongly disagree’ responses
and one point for ‘slightly disagree’ responses: 6, 11, 12, 18, 23, 24, 26, 28, 31, 32, 35,
38, 40, 42, 43, 45, 51, 56, 57, 60. For the EQ questionnaire, the following items were
scored two points for ‘strongly agree’ responses and one point for ‘slightly agree’
responses: 1, 6, 19, 22, 25, 26, 35, 36, 37, 38, 41, 42, 43, 44, 52, 54, 55, 57, 58, 59, 60.
The following items were scored two points for ‘strongly disagree’ responses and one
point for ‘slightly disagree’ responses: 4, 8, 10, 11, 12, 14, 15, 18, 21, 27, 28, 29, 32, 34,
39, 46, 48, 49, 50. The filler items on both questionnaires were not scored.
Based on the total score for the EQ questionnaire, those scoring ranging from 0-32 are
categorized as low in empathizing, typical of individuals with high-functioning autism.
Scores ranging from 33-52 are described as average, 53-63 are above average, and 6480 are very high (Baron-Cohen, 2003). Based on the total score for the SQ questionnaire,
those scoring between 0-19 are categorized as low in systemizing and 20-39 are
average. Scores ranging from 40-50 are categorized as above average, typical of
individuals with high-functioning autism. Scores between 51-80 are categorized as very
21
high in systemizing, where every 1 normal male in the range is matched with 3 males
with high-functioning autism and females rarely score in this range (Baron-Cohen,
2003).
Good test-retest reliability and concurrent validity was demonstrated for the EQ
questionnaire (Baron-Cohen & Wheelwright, 2004; Lawrence, Shaw, Baker, BaronCohen, & David, 2004). Similarly, the SQ questionnaire demonstrated sexual
dimorphism and differentiation between individuals with and without conditions such
as autism and Asperger syndrome (Baron-Cohen, et al., 2003; Goldenfeld, Baron-Cohen,
& Wheelwright, 2005; Wheelwright et al., 2006).
Spatial Categorical and Coordinate Task (SCCT)
The SCCT was adapted from Kosslyn and colleagues’ (1989) study on hemispheric spatial
representation and was proposed as a test of systemizing ability for the current study.
The stimuli were set up using the computer software eprime version 4.0 and presented
on a 14-inch computer screen. Each stimulus consisted of a 1×1mm square dot lying
above or below the midpoint of a horizontal line measuring 10mm long and 1mm thick.
Four blocks of 36 stimuli were displayed on the screen. In each block, 12 stimuli
appeared at 3˚ of visual angle (approximately 26mm) to the left from the center of the
screen, 12 appeared 3˚ of visual angle (approximately 26mm) to the right and 12
appeared in the center of the screen. This set up is based on the human visual pathway
(Figure 1): The left and right visual fields are projected to the right and left halves of the
22
retina, which subsequently relay the information to the right and left hemispheres
respectively. In each set of 12 stimuli, 6 square dots appeared above the line and the
other 6 appeared below the line. For each set of these 6 square dots and lines, 3
appeared within 3mm from the midpoint of the line while the other 3 appeared more
than 3mm from the line. A fixation cross in the center of the screen precedes every
stimulus for 200ms. Each stimulus appeared on the screen for 150ms followed by the
fixation cross in the center of the screen for 1300ms during which the participants
would response (see Appendix B). The stimuli were presented randomly by the
computer. The accuracy and reaction time were recorded by the computer.
Figure 1. The left and right visual field and the pathways leading to the right and left hemispheres of the
visual cortex (Kimura, 2000, p. 140).
23
Other than the instructions, both the categorical and coordinate tasks consisted of
identical stimuli described above. In the categorical task, participants were instructed to
hit the ‘Y’ key on the keyboard with their right index finger if the square dot was above
the line and ‘B’ key with their left index finger if the square dot was below the line. In
the coordinate task, they were told to hit the ‘Y’ key on the keyboard if they think the
square dot is more than 3mm from the line and ‘B’ key if the square dot is less than
3mm from the line. Preceding every block, the participants were instructed to response
as fast and as accurately as they could.
A practice block preceded each task consisting of 12 trials (1 trial for each dot’s
position). Feedback in the form of statements ‘correct’ and ‘incorrect’ were displayed
after every trial for the practice blocks only. The participants were instructed to focus
their attention on a fixation cross which preceded every presentation and, position their
chin on a chin-rest at a viewing distance of 320mm throughout the experiment. The
chin-rest was adjusted to a height such that the line of sight aligned with the middle
portion of the stimuli. The computer screen was tilted such that it was perpendicular to
the table.
The Facial Recognition Task (FERT)
The FERT consisted of grayscale pictures drawn from the National Technological
University in Singapore and volunteers determined by the study team as proficient in
24
expressing accurate facial emotion (See Appendix C). To ascertain the quality of the
facial emotion stimuli, selected stimuli were presented to 6 independent volunteers
who determined what facial emotion each stimulus was from 5 options including
‘neutral’, ‘happy’, ‘sad’, ‘angry’ and ‘fearful’. The stimuli were edited to match the
stimuli developed by Ekman and Friesen (1976) in terms of facial orientation, color and
framing. Each stimulus was subtended by 4.5
˚ horizontally and 7 ˚ vertically and
presented at a viewing distance of 320mm. The lateralized stimuli were positioned at 3˚
of visual angle (approximately 26mm) from the center of the computer screen. The
stimuli consisted of 3 different Chinese male posers and 3 different Chinese female
posers. Chinese ethnicity was selected as it made up the major ethnic proportion of the
population in Singapore.
Four blocks of 108 stimuli were presented on the computer screen. The stimuli were
counterbalanced for facial emotions, sex and spatial positions. In every block, half the
presentations (54 stimuli) were the target stimuli. The participants were instructed to
look for a different facial emotion in each block in the sequence ‘happy’ (block 1), ‘fear’
(block 2), ‘anger’ (block 3) and ‘sadness’ (block 4). Preceding every block was a practice
block and, the participants were instructed to respond as fast and as accurately as they
could. Identical to the SCCT process, a fixation cross in the center of the screen precedes
every stimulus for 200ms. Each stimulus appeared on the screen for 150ms followed by
the fixation cross in the center of the screen for 1300ms during which the participants
would respond. The stimuli were presented randomly by the computer. The accuracy
25
and reaction time were recorded by the computer. The participants were instructed to
hit the ‘Y’ key on the keyboard if the stimulus was the target stimulus and the ‘B’ key if
the stimulus was not the target stimulus. The stimuli were presented using the same
computer and the participants were instructed to position their chin on the chin rest as
of the SCCT.
Prenatal testosterone level
Measuring the length of second (2D) and fourth (4D) digits on the right hand provides a
crude biomarker of prenatal testosterone level (Figure 2). The figures for 2D and 4D
were obtained by measuring the length between the basal crease where the fingers join
the palm and the tip of the fingers with the vernier caliper. The ratio is then computed
by dividing 2D by 4D. (Hamilton, 2009) found that higher levels of testosterone were
associated with lower 2D:4D ratio and that the ratio is reflected in hand dominance. The
internal reliability of the 2D:4D measure was previously reported to range between r =
.990 to .998 (Putz, et al., 2004).
26
Figure 2. Obtaining the measurement for the second and fourth finger digit lengths.
27
Chapter 3
3.1
Results
Characteristics of the sample
3.1.1 Demographics of the sample
Table 1 shows the results for the univariate analyzes. The 2D:4D finger digit ratio is used
as a measure of prenatal testosterone level, dichotomized arbitrarily as values below 0
(masculine) and above 0 (feminine). Values equal to 0 is categorized separately as
‘neutral’ and are not included in the analysis. Similarly, previous studies dichotomized
the 2D:4D finger digit ratio between the two hands using 0 as the dichotomizing value
(Voracek, Dressler, & Manning, 2007) and, using a median split (Tottenham, 2006).
28
Table 1. Characteristics of the sample (n=105).
Mean
SD
Observed minimum
Observed maximum
Age
22.10
2.63
19
34
Systemizing score
29.20
10.74
9
59
Empathizing score
36.79
9.52
18
72
Finger digit ratio
0.97
0.03
0.90
1.06
N
%
Low
19
18.4
Average
67
65.0
Above Average
13
12.6
Very High
4
3.9
Low
32
31.1
Average
67
65.0
Above Average
1
1.0
Very High
3
2.9
Masculine
80
77.7
Feminine
19
18.4
Neither
4
3.9
Systemizing category
Empathizing category
2D:4D category
3.1.2 Cognitive styles and the correlates
The categories for systemizing and empathizing were set based on Baron Cohen’s (2003)
convention. The 2D:4D finger digit ratio was dichotomized into feminine and masculine
for ratios greater than 1.0 and lesser than 1.0 respectively. Those with identical 2D:4D
finger digit lengths were categorized as a separate group i.e. ‘Neither’. Bivariate
29
Pearson’s product-movement correlation coefficient (r) for the continuous variables was
calculated and one-way between groups analysis of variance (ANOVA) was used to
examine the relationship for the categorical variables. No correlation was observed
between systemizing and empathizing cognitive style. The 2D:4D finger digit ratio is not
indicative of these two cognitive styles.
3.2
Cognitive styles (systemizing/empathizing) and cognition
3.2.1 Aims and analysis
In this section, the participants’ cognitive styles and their performance on the spatial
categorical, the spatial coordinate and the facial emotion recognition tasks were
examined. The accuracy of the task was determined by examining the total number of
correct responses obtained by adding up the scores for the correct responses across the
four blocks. Both the accuracy and the reaction times for the correct responses were
considered in the analyses. 2 × 2 repeated measures ANOVA were conducted, with visual
field (RVF/LVF) as the within subjects variables and the cognitive styles (systemizing and
empathizing) as the between groups variables were.
30
3.2.2 Spatial categorical task
Accuracy (Systemizing cognitive styles)
A main effect for the systemizing groups was found (F [1, 100] = 5.807, p < .05). Post hoc
analyses with Bonferroni correction for multiple comparisons revealed that the ‘high’
systemizing group had significantly lower mean number of correct responses than the
‘low’ systemizing group (Figure 3). No interactions were found on the basis of
systemizing groups.
Reaction time (Systemizing cognitive styles)
A main effect for the systemizing groups was found (F [1, 99] = 8.497, p < .01). Post hoc
analyses with Bonferroni correction revealed that the ‘high’ systemizing group had
significantly slower mean reaction time than the ‘low’ systemizing group (Figure 3). No
interactions were found on the basis of systemizing groups.
31
Figure 3. Accuracy and reaction time between the two systemizing groups for stimuli presented in the
right visual field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH).
Accuracy (Empathizing cognitive styles)
A main effect for the empathizing groups was found (F [1, 100] = 8.891, p < .01). Post
hoc analyses with Bonferroni revealed that the ‘high’ empathizing group had
significantly lower number of correct responses than the ‘low’ empathizing group
(Figure 4). No interactions were found on the basis of empathizing groups.
Reaction time (Empathizing cognitive styles)
No significant main effect or interaction effect was observed for the mean reaction time
between the empathizing groups for stimuli presented between the RVF/LH and
LVF/RH.
32
Figure 4. Accuracy between the two empathizing groups for stimuli presented in the right visual field
(RVF)/left hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH).
3.2.3 Spatial coordinate task
Accuracy (Systemizing cognitive styles)
No significant main effect or interaction effect was observed for the mean number of
correct responses between the systemizing groups for stimuli presented between the
RVF/LH and LVF/RH.
Reaction time (Systemizing cognitive styles)
A main effect for the visual field was found (F [1, 100] = 8.386, p < .01). Post hoc
analyses with Bonferroni indicated a left visual field/right hemispheric (LVF/RH)
advantage (Figure 5). No interactions were found on the basis of systemizing groups.
33
Figure 5. Reaction time between the two empathizing groups for stimuli presented in the right visual
field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH).
Accuracy (Empathizing cognitive styles)
No significant main effect or interaction effect was observed for the mean number of
correct responses between the empathizing groups for stimuli presented between the
RVF/LH and LVF/RH.
Reaction time (Empathizing cognitive styles)
A main effect for the visual field was found (F [1, 100] = 4.095, p < .05). Post hoc
analyses with Bonferroni indicated a left visual field/right hemispheric (LVF/RH)
advantage (Figure 6). No interactions were found on the basis of systemizing groups.
34
Figure 6. Reaction time between the two empathizing groups for stimuli presented in the right visual
field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH).
3.2.4 Facial emotion recognition task (FERT)
Separate analyses were conducted for the male and female facial emotion stimuli. Only
the significant results are reported herein.
Happy facial emotion (Systemizing cognitive styles)
For the ‘happy’ male facial emotion, no main effects were found on the basis of
accuracy but there was a significant interaction between visual field and systemizing
group (F [1, 97] = 5.214 p < .05) (Figure 7). No main effects or interaction effects were
found on the basis of mean reaction time.
35
Figure 7. Accuracy between the two systemizing groups for ‘happy’ male facial emotion presented in
the right visual field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH).
Angry facial emotion (Systemizing cognitive styles)
For the ‘angry’ female facial emotion, no main effects were found on the basis of
accuracy but there was a significant interaction between visual field and systemizing
group (F [1, 97] = 5.341, p < .05) (Figure 8). No main effects or interaction effects were
found on the basis of mean reaction time.
36
Figure 8. Accuracy between the two systemizing groups for ‘angry’ female facial emotion presented in
the right visual field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH).
Sad facial emotion (Systemizing cognitive styles)
For the ‘sad’ facial emotion, no significant main effect and interaction effect was
observed for both the accuracy and the mean reaction time.
Fearful facial emotion (Systemizing cognitive styles)
For the ‘fearful’ facial emotion, no significant main effect and interaction effect was
observed for both the accuracy and the mean reaction time.
Happy facial emotion (Empathizing cognitive styles)
For the ‘happy’ facial emotion, no significant main effect and interaction effect was
observed for both the accuracy and the mean reaction time.
37
Angry facial emotion (Empathizing cognitive styles)
For the ‘angry’ female facial emotion, a main effect for the mean reaction time between
the visual fields was found (F [1, 93] = 8.507, p < .01). Post hoc analyses with Bonferroni
correction indicated a left visual field/right hemispheric (LVF/RH) advantage (Figure 9). A
main effect for the mean reaction time between the empathizing groups was found (F
[1, 93] = 13.910, p < .01). Post hoc analyses with Bonferroni revealed that the ‘high’
empathizing group had significantly slower mean reaction time than the ‘low’
empathizing group (Figure 9). There was a significant interaction between visual field
and empathizing group (F [1, 93] = 9.955, p < .01) (Figure 9).
Figure 9. Mean reaction time between the two empathizing groups for ‘angry’ female facial emotion
presented in the right visual field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right
hemisphere (RH).
38
Sad facial emotion (Empathizing cognitive styles)
For the ‘sad’ male facial emotion, a main effect for the accuracy on the empathizing
group was found (F [1, 97] = 4.056, p < .05). Post hoc analyses with Bonferroni revealed
that the ‘high’ empathizing group had significantly higher number of correct responses
than the ‘low’ empathizing group (Figure 10). A main effect for the mean reaction time
on the empathizing group was found (F [1, 97] = 8.343, p < .01). Post hoc analyses with
Bonferroni revealed that the ‘high’ empathizing group had significantly slower reaction
time than the ‘low’ empathizing group (Figure 10).
Figure 10. Accuracy and reaction time between the two empathizing groups for ‘sad’ male facial
emotion presented in the right visual field (RVF)/left hemisphere (LH) and the left visual field
(LVF)/right hemisphere (RH).
39
For the ‘sad’ female facial emotion, no main effects were found on the basis of accuracy
but there was a significant interaction between visual field and empathizing group (F [1,
97] = 4.512, p < .05) (Figure 11).
Figure 11. Accuracy between the two empathizing groups for ‘sad’ female facial emotion presented in
the right visual field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH).
Fearful facial emotion (Empathizing cognitive styles)
For the ‘fearful’ female facial emotion, a main effect for the reaction time on the
empathizing group was found (F [1, 97] = 4.585, p < .05). Post hoc analyses with
Bonferroni revealed that the ‘high’ empathizing group had significantly slower reaction
time than the ‘low’ empathizing group (Figure 12).
40
Figure 12. Reaction time between the two empathizing groups for ‘fearful’ female facial emotion
presented in the right visual field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right
hemisphere (RH).
3.3
2D:4D finger digit ratio and cognition
3.3.1 Aims and analysis
In this section, the participants’ 2D:4D finger digit ratio and their performance on the
spatial categorical, spatial coordinate and the facial emotion recognition tasks was
examined. For the spatial categorical and spatial coordinate tasks, the accuracy of the
tasks was determined by examining the total number of correct responses obtained by
adding up the scores for the correct responses across the four blocks. Both the accuracy
and the reaction times for the correct responses were considered in our analyses. 2 × 2
repeated measures
ANOVA
was conducted, with visual field (RVF/LVF) as the within
41
subjects variables and the 2D:4D group (masculine and feminine) as the between groups
variables were. The right hand’s 2D:4D finger digit ratio was used in the analyses as it
was suggested to be more indicative of prenatal testosterone level, compared to the left
hand (Lutchmaya, et al., 2004; Manning, Scutt, Wilson, & Lewis-Jones, 1998). In
addition, we also exclude participants with 2D:4D finger digit ratio equals to 1.0 as it did
not enable us to categorize them as masculine or feminine.
3.3.2 Spatial categorical task
Accuracy
No significant main effect and interaction effect was observed for the mean number of
correct responses between the ‘masculine’ and ‘feminine’ groups for stimuli presented
between the RVF/LH and LVF/RH.
Reaction time
A main effect for the visual field was found (F [1, 95] = 5.311, p < .05). Post hoc analyses
with Bonferroni indicated a right visual field/left hemispheric (RVF/LH) advantage
(Figure 13). No interactions were found on the basis of 2D:4D ratio groups.
42
Figure 13. Reaction time between the ‘masculine’ and ‘feminine’ groups for stimuli presented in the
right visual field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH).
3.3.3 Spatial coordinate task
Accuracy
No significant main effect and interaction effect was observed for the mean number of
correct responses between the ‘masculine’ and ‘feminine’ groups for stimuli presented
between the RVF/LH and LVF/RH.
Reaction time
A main effect for the visual field was found (F [1, 96] = 5.563, p < .05). Post hoc analyses
with Bonferroni indicated a left visual field/right hemispheric (LVF/RH) advantage
(Figure 14). No interactions were found on the basis of 2D:4D ratio groups.
43
Figure 14. Reaction time between the ‘masculine’ and ‘feminine’ groups for stimuli presented in the
right visual field (RVF)/left hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH).
3.3.4 Facial emotion recognition task
A separate analysis was conducted for the male and female facial emotion stimuli. Only
the significant results are reported herein. No significant main effect and interaction
effect was observed for both accuracy and mean reaction time for all the facial emotion
stimuli.
3.4
Summary of findings
Table 2 presents the overall summary findings for the spatial categorization task and
spatial coordinate task. Table 3 presents the overall summary findings for the four facial
emotion recognition task. While the study dichotomized the 2D:4D finger digit ratio into
44
values below 0 (masculine) and above 0 (feminine), correlation analysis using 2D:4D
finger digit ratio as a continuous value demonstrated similar results with the facial
emotion recognition task. For example, increasing 2D:4D finger digit ratio (more
feminine) is correlated with greater number of correct responses for female happy facial
emotion displayed to the right hemisphere, r = .21, p < .05, and left hemisphere, r = .22,
p L)
M* (LH)
SPATIAL COORDINATE TASK
Systemizing
Empathizing
2D:4D ratio
M* (RH)
M* (RH)
M* (RH)
M = significant main effect
RH = right hemispheric advantage, LH = left hemispheric advantage
H = High systemizing/empathizing group, L = Low systemizing/empathizing
group
* p < .05, ** p < .01
45
Table 3. Summary findings on the facial emotion recognition task.
Male stimuli
(Accuracy)
Systemizing
Empathizing
2D:4D ratio
I*
-
HAPPY
Male stimuli
Female stimuli
(Reaction time)
(Accuracy)
-
Female stimuli
(Reaction time)
-
-
ANGRY
Systemizing
Empathizing
-
-
I*
-
2D:4D ratio
-
-
-
M** (RH)
M** (H > L)
I**
-
I*
-
-
-
M* (H > L)
-
SAD
Systemizing
Empathizing
2D:4D ratio
M* (H > L)
-
M** (H > L)
FEARFUL
Systemizing
Empathizing
2D:4D ratio
-
-
M = significant main effect, I = significant interaction effect
RH = Right hemispheric advantage
H = High systemizing/empathizing group, L = Low systemizing/empathizing
group
* p < .05, ** p < .01
46
Chapter 4
Discussion
The overarching aim of the study was to investigate the influence of cognitive styles and
prenatal testosterone level on spatial cognition and social cognition. The study uses
Baron-Cohen’s (2003) questionnaire on systemizing and empathizing cognitive styles,
and the 2D:4D finger digit ratios as the measure of prenatal testosterone level. An
adaptation of the spatial categorization and spatial coordinate task from Kosslyn and
colleagues’ (1989) experiment was used as the spatial cognition task, and a novel facial
emotion recognition task methodologically modeled after the spatial task was devised
as the social cognition task.
For the spatial cognition task, only main effects were observed for both cognitive styles
and 2D:4D finger digit ratio. For the social cognition task, both main effects and
interaction effects were observed for cognitive styles but only main effects were
observed for the 2D:4D finger digit ratio.
Overall, the results are broadly consistent with the existing literature in so far as the
results indicated that individual differences in cognition are observed through cognitive
style and 2D:4D finger digit ratio. No correlation was observed between cognitive styles
and 2D:4D finger digit ratio indicating that these two concepts are distinct from each
other. More detailed review of the findings in relation to the literature is provided in the
following sections.
47
4.1
Cognitive styles (systemizing/empathizing) and cognition
For the spatial task, the results indicated that individuals who scored ‘high’ on
systemizing performed worse than those who scored ‘low’ for the spatial categorization
task. This contradicts the expectation that high systemizers should perform better on
the task. However, the results are consistent with Kosslyn and colleagues’ (1989)
findings that the spatial coordinate task is a right hemispheric task. The results did not
reveal interaction between cognitive styles and functional asymmetry.
The current study’s spatial task is qualitatively different from other spatial tasks such as
the mental rotation or targeting task which have previously shown better performance
among systemizers (Baron-Cohen, 2003; Cook & Saucier, 2010). This difference could
account for the findings on the spatial categorization task. The previous studies’ spatial
tasks entail manipulation of spatial information such as mentally rotating three
dimensional figures and comparing them to the target figure, while the current spatial
task is a linguistic task i.e. identifying if a dot is above or below a line. In addition,
previous studies looked at differences between men and women (Baron-Cohen, 2003;
Cook & Saucier, 2010). As such, within sex differences could entail different pattern in
cognitive performance although overall performance is still better than women.
48
For the social task, the results indicated that high empathizers performed better in
terms of accuracy for male sad facial emotion, in concordance with the cognitive styles
concept. However, high empathizers showed slower reaction times for male sad facial
emotion, female angry facial emotion and female fearful facial emotion. As such, it is
plausible that high empathizers are more accurate in recognizing facial emotions at the
expense of processing speed. Although this appear to be the case based on the results
for male sad facial emotion, the lack of significant findings on accuracy for female angry
and fearful facial emotion precludes any conclusive statement.
In line with previous research (Bourne & Maxwell, 2010; Dimberg & Petterson, 2000),
the present study found dominance in the right hemisphere for facial emotion
recognition, particularly for the female angry facial emotion. In addition, this effect was
especially so for the group who reported higher empathizing. This indicates that high
empathizers demonstrate greater lateralization in the recognition of female angry facial
emotion pertaining to the reaction time. This finding is analogous to the study which
revealed that psychologically feminine males showed greater right hemispheric bias for
angry emotion (Bourne & Maxwell, 2010). A congruent finding was also reported in a
previous study looking at facial muscular reaction to angry facial stimuli. Greater facial
muscular reaction towards angry stimuli was found on the left side of the face indicating
the involvement of the right hemisphere (Dimberg & Petterson, 2000).
49
With respect to systemizing, low systemizers were more accurate while high systemizers
were less accurate when the angry female facial emotion was presented to the right
hemisphere compared to the left hemisphere. An opposite pattern was observed for the
happy male facial emotion. In this case, low systemizers were less accurate while high
systemizers were more accurate when the stimuli were presented to the right
hemisphere compared to the left hemisphere. Taken together, high systemizers
exhibited right hemispheric bias for happy male facial emotion and left hemispheric bias
for angry female facial emotion. The opposite is true for low systemizers. While it is not
clear whether this difference is attributable to the fact that the stimuli differ in the sex
or the type of facial emotion, previous research has shown qualitative differences
between happy and angry emotion stimuli. It has been demonstrated that negative and
positive emotions are generally processed in the right and left hemispheres respectively
(Davidson, 1992, 1995; Jansari, Tranel, & Adolphs, 2000; Mandal, et al., 2008). Hence,
corresponding differences pertaining to hemispheric bias for angry and happy stimuli
are expected in the present sample. Although the influence attributable to the sex of
the stimuli could not be firmly determined for the reason that the actors’ portrayals of
the facial emotion were not rated, there is evidence that while ratings for female stimuli
were more extreme compared to male stimuli for the happy and angry facial emotions,
there is no distinction on how both male and female participants perceived the stimuli
(Dimberg & Lundquist, 1990). Furthermore, a study demonstrated that while men and
women showed different sensitivity towards male/female happy and sad stimuli, their
ability to recognize facial emotions for the different sex stimuli is not affected (Erwin et
50
al., 1992). As such, the present differential results between the two systemizing groups
may be largely attributable to the facial emotion type of the stimuli.
Taken together, the results indicated cognitive styles as predictive of facial emotion
recognition and spatial categorization task but not for spatial coordinate task.
Specifically, both cognitive styles and functional asymmetry are involved in the
recognition of the happy male and angry female facial emotions.
4.2
2D:4D finger digit ratio and cognition
For the spatial task, the 2D:4D finger digit ratio does not predict cognitive performance.
Hence, the hormonal effect on spatial cognition (Collaer, et al., 2007; Kimura, 2000, p.
179) is not supported. However, the results are in line with Kosslyn and colleagues’
(1989) findings on functional asymmetry for two discernible spatial processing i.e. left
hemispheric advantage for the spatial categorization task and right hemispheric
advantage for the spatial coordinate task.
Similar to experiments looking at visuospatial performance for varying cognitive styles,
experiments which looked at the association between 2D:4D finger digit ratio and
spatial cognition have typically utilized spatial tasks that require manipulation of spatial
stimuli. This could account for the lack of significant findings because the spatial task
utilized in the current study is fundamentally different from the previous tasks. For
51
instance, a previous study employed the Judgment of Line Angle and Position test
(Guapo et al., 2009) where one strategy participants might use is to mentally shift the
line to match the target line. This contrasts with the present spatial task as participants
only need to recognize the position of the line.
Results from the social task did not support the hypothesis and previous studies that
demonstrated that higher 2D:4D finger digit ratio, i.e. a feminine pattern, is associated
with greater social cognitive ability. This suggests that 2D:4D finger digit ratio is not a
viable predictor of both spatial and social tasks. However, it is notable that the nature of
the cognitive tasks is different from other tasks. Particularly, it is possible that the
present tasks tap into the aforementioned classification-driven system as opposed to
the expectancy-driven system at least for the social task (Borst, et al., 2011).
Unfortunately, comparative task such as the mental rotation task, which is likely a
classification-driven task, was not included to examine if the two types of cognitive tasks
represent different cognitive systems.
4.3
Limitations and future directions
A major omission in the present study is the absence of data from the female
population. The present scale and support for the present study did not allow for the
inclusion of female participants. While comparison with previous studies provides
evidence for the notion that within-sex cognitive differences is distinct from those of
52
between-sex, future studies should include female participants given identical set of
experiments. One such example comes from Kimura’s (1996) study which observed that
low testosterone level among men is associated with greater spatial ability compared to
men with high testosterone levels but the reverse is true for women. In addition, brain
imaging studies that examine the same methodological features can be informative
pertaining to the notion of sexual dimorphism, within sex differences and functional
asymmetry.
The finger digit length measure as a marker for prenatal testosterone level is not a
perfect indicator considering that it has led to inconsistent findings with respect to
cognitive abilities including spatial ability (see Cohen-Bendahan, et al., 2005).
Unfortunately, the only reliable method to counter this issue is to measure intrauterine
testosterone level and follow up with cognitive tests longitudinally and this is practically
difficult to achieve. Nonetheless, van Honk and colleagues found that circulating
testosterone effect on the identification of emotion in the eyes area is observed only for
female subjects with the masculine 2D:4D finger digit ratio but not for those with the
feminine version (van Honk, et al., 2011). As such, future studies should examine if
intrauterine measures would generate similar findings with current correlates.
It might be informative to examine the distinction in cognition between individuals who
are exclusively high on systemizing (those who score a systemizing quotient >50) and
those who are exclusively high on empathizing (those who score an empathizing
53
quotient >63). However, the present sample did not have the minimum number of
individuals in such groups to enable data analysis. With reference to the present sample,
people generally reported ratings close to the average for both systemizing and
empathizing. Considering this, the data is informative with respect to the cognitive
performance among the average individuals.
4.4
General conclusion
This study provides novel observations derived from two methodologically comparable
cognitive tasks and their association with functional asymmetry within the concepts of
cognitive styles and 2D:4D finger digit ratio.
The lack of congruency in the results between cognitive styles and spatial cognitive
performance suggests that cognitive style may not be a predictor for spatial abilities.
Similarly, no significant relationship was observed between both the cognitive tasks and
the 2D:4D finger digit ratio. In contrast, functional asymmetry is observed for both
spatial and social tasks and the results are consistent with previous findings. Taken
together, this suggests that functional asymmetry compared to cognitive styles or 2D:4D
finger digit ratio, is a better predictor for spatial and social cognition.
Findings from this study support the notion that there are observable within-sex
differences for cognition. However, further research is necessary to examine if between54
sex differences demonstrate similar or varying patterns compared to within-sex
observation. As such, it remains unclear if within-sex differences are analogous to
between-sex differences.
In light of the present findings, the oversimplified convention of left and right
hemispheric specialization in verbal and spatial information respectively should be
reexamined particularly in the context of cognitive styles and hormonal factors. It is
apparent from the present spatial task data that subdomains within a cognitive area can
demonstrate differential functional asymmetry. Furthermore, the current findings based
on cognitive style and 2D:4D finger digit ratio add on to a growing body of research
which demonstrated that within facial emotion recognition, different emotions can
generate differential hemispheric biases.
55
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61
Appendix A – Systemizing/empathizing questionnaire
The Systemizing Quotient
1.
When I listen to a piece of music, I always
notice the way it’s structured.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I watch a film, I prefer to be with a
group of friends, rather than alone.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I am interested in learning about different
religions.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I rarely read articles or web pages about new
technology.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I do not enjoy games that involve a high
degree of strategy.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
2.
I adhere to common superstitions.
3.
I often make resolutions, but find it hard to
stick to them.
4.
I prefer to read non-fiction than fiction.
5.
If I were buying a car, I would want to obtain
specific information about its engine capacity.
6.
7.
8.
9.
10.
11.
12.
When I look at a painting, I do not usually
think about the technique involved in making
it.
It there was a problem with the electrical
wiring in my home, I’d be able to fix it myself.
When I have a dream, I find it difficult to
remember precise details about the dream the
next day.
13.
I am fascinated by how machines work.
14.
I make it a point of listening to the news each
morning.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
In maths, I am intrigued by the rules and
patterns governing numbers.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I am bad about keeping in touch with old
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
15.
16.
62
friends.
17.
18.
19.
20.
When I am relating a story, I often leave out
details and just give the gist of what
happened.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I find it difficult to understand instruction
manuals for putting appliances together.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I look at an animal, I like to know the
precise species it belongs to.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
If I were buying a computer, I would want to
know exact details about its hard drive
capacity and processor speed.
21.
I enjoy participating in sport.
22.
I try to avoid doing household chores if I can.
23.
When I cook, I do not think about exactly how
different methods and ingredients contribute
to the final product.
24.
I find it difficult to read and understand maps.
25.
If I had a collection (eg. CDs, coins, stamps), it
would be highly organized.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I look at a piece of furniture, I do not
notice the details of how it was constructed.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
The idea of engaging in ‘risk-taking’ activities
appeals to me.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I learn about historical events, I do not
focus on exact dates.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I learn a language, I become intrigued by
its grammatical rules.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I find it difficult to learn my way around a new
city.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
26.
27.
28.
29.
30.
31.
32.
When I read the newspaper, I am drawn to the
tables of information, such as football league
scores or stock market indices.
I do not tend to watch science documentaries
on television or read articles about science and
63
nature.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
If I were buying a stereo, I would want to know
about its precise technical features.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I find it easy to grasp exactly how odds work in
betting.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I am not very meticulous when I carry out
D.I.Y.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I find it easy to carry on a conversation with
someone I’ve just met.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I look at a building, I am curious about
the precise way it was constructed.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When an election is being held, I am not
interested in the results for each constituency.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I lend someone money, I expect them to
pay me back exactly what they owe me.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When travelling by train, I often wonder
exactly how the rail networks are coordinated.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I buy a new appliance, I do not read the
instruction manual very thoroughly.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
If I were buying a camera, I would not look
carefully into the quality of the lens.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I read something, I always notice
whether it is grammatically correct.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I hear the weather forecast, I am not
very interested in the meteorological patterns.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I often wonder what it would be like to be
someone else.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I find it difficult to understand information the
bank sends me on different investment and
saving systems.
47.
I find it difficult to do two things at once.
48.
When I look at a mountain, I think about how
precisely it was formed.
64
49.
50.
51.
52.
53.
54.
55.
I can easily visualize how the expressways in
my region link up.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I’m in a restaurant, I often have a hard
time deciding what to order.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
When I’m in a plane, I do not think about the
aerodynamics.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I often forget the
conversations I’ve had.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
precise
details
of
When I am walking in the country, I am curious
about how the various kinds of trees differ.
After meeting someone just once or twice, I
find it difficult to remember precisely what
they look like.
I am interested in knowing the path a river
takes from its source to the sea.
56.
I do not read legal documents very carefully.
57.
I am not interested in understanding how
wireless communication works.
58.
I am curious about life on other planets.
59.
When I travel, I like to learn specific details
about the culture of the place I am visiting.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I do not care to know the names of the plants I
see.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
60.
65
The Empathizing Quotient
1.
I can easily tell if someone else wants to enter
a conversation.
2.
I prefer animals to humans.
3.
I try to keep up with the current trends and
fashions.
4.
I find it difficult to explain to others things that
I understand easily, when they don’t
understand it first time.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
5.
I dream most nights.
6.
I really enjoy caring for other people.
7.
I try to solve my own problems rather than
discussing them with others.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I find it hard to know what to do in a social
situation.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
8.
9.
I am at my best first thing in the morning.
10.
People often tell me too much if I went too far
in driving my point home in a discussion.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
It doesn’t bother me too much if I am late
meeting a friend.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Friendships and relationships are just too
difficult, so I tend not to bother with them.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I would never break a law, no matter how
minor.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I often find it difficult to judge if something is
rude or polite.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
11.
12.
13.
14.
15.
In a conversation, I tend to focus on my own
thoughts rather than on what my listener
might be thinking.
16.
I prefer practical jokes to verbal humor.
17.
I live life for today rather than the future.
66
18.
19.
20.
21.
22.
23.
When I was a child, I enjoyed cutting up worms
to see what would happen.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I can pick up quickly if someone says one thing
but means another.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I tend to have very strong opinions about
morality.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
It is hard for me to see why some things upset
people so much.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I find it easy to put myself in somebody else’s
shoes.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I think that good manners are the most
important thing a parent can teach their child.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
If anyone asked me if I liked their haircut, I
would reply truthfully, even if I didn’t like it.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I can’t always see why someone should have
felt offended by a remark.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
People often tell me that I am very
unpredictable.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I enjoy being the centre of attention at any
social gathering.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
24.
I like to do things on the spur of the moment.
25.
I am good at predicting how someone will feel.
26.
I am quick to spot when someone in a group is
feeling awkward or uncomfortable.
27.
28.
29.
30.
31.
If I say something that someone else is
offended by, I think that that’s their problem,
not mine.
32.
Seeing people cry doesn’t really upset me.
33.
I enjoy having discussions about politics.
34.
I am very blunt, which some people take to be
rudeness, even though this is unintentional.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I don’t tend to find social situations confusing.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
35.
67
36.
37.
Other people tell me I am good at
understanding how they are feeling and what
they are thinking.
When I talk to people, I tend to talk about
their experiences rather than my own.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
38.
It upsets me to see an animal in pain.
39.
I am able to make decisions without being
influenced by people’s feelings.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I can’t relax until I have done everything I had
planned to do that day.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I can easily tell if someone else is interested or
bored with what I am saying.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I get upset if I see people suffering on news
programmes.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
People sometimes tell me that I have gone too
far with teasing.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I would be too nervous to go on a big rollercoaster.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Other people often say that I am insensitive,
though I don’t always see why.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
If I see a stranger in a group, I think that it is up
to them to make an effort to join in.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I usually stay emotionally detached when
watching a film.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
Friends usually talk to me about their
problems as they say that I am very
understanding.
I can sense if I am intruding, even if the other
person doesn’t tell me.
I often start new hobbies but quickly become
bored with them and move on to something
else.
I like to be very organized in day to day life and
often make lists of the chores I have to do.
68
52.
I can tune into how someone else feels rapidly
and intuitively.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
53.
I don’t like to take risks.
54.
I can easily work out what another person
might want to talk about.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I can tell if someone is masking their true
emotion.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Before making a decision I always weigh up
the pros and cons.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I don’t consciously work out the rules of social
situations.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
55.
56.
57.
58.
I am good at predicting what someone will do.
59.
I tend to get emotionally involved with a
friend’s problems.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
I can usually appreciate the other person’s
viewpoint, even if I don’t agree with it.
Strongly agree
Slightly agree
Slightly disagree
Strongly disagree
60.
69
Appendix B – Display for Spatial Categorical and Coordinate Task (SCCT)
Fixation
200ms
Stimulus
150ms
Fixation/Response
1500ms
Time
Stimulus
150ms
Fixation/Response
1500ms
……
N.B. Diagram not drawn to scale
70
Appendix C – Facial emotion stimuli
Male facial emotion stimuli
Happy
Angry
Sad
Fearful
71
Female facial emotion stimuli
Happy
Angry
Sad
Fearful
72
[...]... Bellack, Morrison, & Wixted, 1990) In the cognitive domain, men and women display varying aptitudes such as the mental rotation task, the embedded figure test, verbal fluency and emotion recognition (BaronCohen, 2003) Men generally perform better on spatial tasks while women perform better on tasks involving facial emotions (Baron-Cohen, 2003; Hamilton, 2009; Kimura, 2000) In at least one study, men... recognition of fearful and happy faces (Breiter et al., 1996) While left activation for certain facial emotions is specific to certain brain regions, the right hemisphere as a whole was associated with the recognition of most facial emotions For example, right hemisphere dominance and greater lateralization for recognition of emotions in men was reported recently (Bourne & 16 Maxwell, 2010; Grimshaw, et al.,... effects of sex hormones on human cognition and the importance of sex hormones for brain development For example, males with Idiopathic Hypogonadtrophic Hypogonadism or Androgen Insensitivity, a condition where there is deficiency in testosterone, have been shown to demonstrate poorer performance in spatial tasks compared to healthy males (Kimura, 2000, p 179) Females who are born with Congenital Adrenal... processing negative emotions while the left hemisphere processes positive emotions (Mandal, Asthana, & Biswal, 2008, p 138) In contrast, the activation of the right hemisphere was stronger in response to the recognition of the happy side of chimeric facial stimuli, which was found to be related to empathy among female subjects only (Rueckert & Naybar, 2008) It was previously mentioned that behavioral... the associations between (1) cognitive styles with spatial and social cognition; (2) 2D:4D finger digit ratio with spatial and social cognition Two issues in the extant literature are addressed in this study The central issue the current study sought to resolve is the inconsistent findings in the functional asymmetry of visual-spatial performance and facial emotion recognition The secondary issue to... level However, a discussion on intelligence and neural network mentioned that even classification of stimuli on a perceptual level could involve higher level influence (Hawkins & Blakeslee, 2004) Taking all into consideration, the experiments in the present study are constructed as classification-driven tasks that tap on perceptual cognitive processing Additionally, functional asymmetry is examined... reliability and concurrent validity was demonstrated for the EQ questionnaire (Baron-Cohen & Wheelwright, 2004; Lawrence, Shaw, Baker, BaronCohen, & David, 2004) Similarly, the SQ questionnaire demonstrated sexual dimorphism and differentiation between individuals with and without conditions such as autism and Asperger syndrome (Baron-Cohen, et al., 2003; Goldenfeld, Baron-Cohen, & Wheelwright, 2005; Wheelwright... which concurrently examine both spatial and social cognition In addition to administrating both types of cognitive tasks to the subjects, qualitatively similar tasks were used to test these two types of cognition A previous spatial task (Kosslyn, et al., 1989) is used and a new social task that mirrors the presentation of the spatial task is devised For both the tasks, the accuracy and reaction 18 time... the National Technological University in Singapore and volunteers determined by the study team as proficient in 24 expressing accurate facial emotion (See Appendix C) To ascertain the quality of the facial emotion stimuli, selected stimuli were presented to 6 independent volunteers who determined what facial emotion each stimulus was from 5 options including ‘neutral’, ‘happy’, ‘sad’, ‘angry’ and ‘fearful’... structural and functional asymmetry Functional asymmetry refers to the notion that the left hemisphere is predominantly “described as analytic or concerned with sequential processing, whereas the right is considered to be concerned with the integration of information over space and time, a holistic or gestalt processor” (Bryden, 1982, p 2) An example of structural asymmetry is the wider right frontal region ... rotation task, the embedded figure test, verbal fluency and emotion recognition (BaronCohen, 2003) Men generally perform better on spatial tasks while women perform better on tasks involving facial. .. regions, the right hemisphere as a whole was associated with the recognition of most facial emotions For example, right hemisphere dominance and greater lateralization for recognition of emotions... hemisphere (LH) and the left visual field (LVF)/right hemisphere (RH) 3.2.4 Facial emotion recognition task (FERT) Separate analyses were conducted for the male and female facial emotion stimuli Only the
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