An evaluation of early and late stage attentional processing of positive and negative information in dysphoria

COGNITION AND EMOTION 2007, 21 (4), 789 Á815 An evaluation of early and late stage attentional processing of positive and negative information in dysphoria Matthew S Shane and Jordan B Peterson University of Toronto, Toronto, Ontario, Canada Depressive disorders may be characterised by hyperattention toward negative information, hypoattention toward positive information, or a combination of both processing biases In two studies, a dot-probe task was utilised to better ascertain the specific direction and time-course of these biases In both studies, the dysphoric group showed significantly less attentional allocation toward positive stimuli than the non-dysphoric group In study two, the dysphoric group also showed greater attentional allocation toward depression-specific stimuli Importantly, the bias toward depression-specific stimuli, and the bias away from positive stimuli, were uncorrelated with each other It may be that both biases can act as sufficient, but not necessary, characteristics of dysphoric processing An additional possibility is that the relative level of each bias type may best characterise dysphoric processing Each of these possibilities is discussed in turn A current controversy in research on information processing in depression concerns the existence and nature of attentional biases in depressed individuals Cognitive models based on schemas (Beck, 1976) or associative networks (Bower, 1981) predict that individuals with depressive disorders should show mood-congruent processing biases at all stages of attentional processing (Ingram, Miranda, & Segal, 1998) Thus, according to these models, depressed individuals should manifest hypervigilant orienting towards negatively valenced information in their current environment (early stage attentional processing) as well as increased sustained attention and Correspondence should be addressed to: Matthew S Shane, Clinical Cognitive Neuroscience Laboratory, The MIND Institute, 1201 Yale Blvd NE, Albuquerque, NM 87131, USA E-mail: mshane@themindinstitute.org This research was supported by the Social Sciences and Humanities Research Council of Canada We gratefully acknowledge Chad Ebesutani and Laura Elinson for their help with data collection, and a number of anonymous reviewers for their excellent feedback # 2007 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business www.psypress.com/cogemotion DOI: 10.1080/02699930600843197 790 SHANE AND PETERSON rumination (later stage attentional processing) on such negative information (see Posner & Peterson, 1990, or LaBerge, 1995, for a discussion of early and late stage attentional processing) Empirical support for these hypotheses has been mixed, however While a number of studies have identified such mood-congruent processing biases (Bradley, Mogg, & Lee, 1997; Gotlib & Cane, 1987; Ingram & Ritter, 2000; Mogg, Bradley, & Williams, 1995), others have failed to identify such biases (Hill & Dutton, 1989; MacLeod, Mathews, & Tata, 1986) Conversely, still other studies have reported that depression may be characterised by a lack of attentional bias towards positive information, rather than an active bias towards negative information (Gotlib, McLachlan, & Katz, 1988; McCabe & Gotlib, 1995; McCabe, Gotlib, & Martin, 2000) This inconsistency has made it difficult for researchers to form definitive conclusions regarding the nature of attentional processing in depressive disorders A variety of methodologies have been adapted from cognitive psychology to investigate selective attention in depressive and anxious disorders, including the emotional Stroop task (Mathews & MacLeod, 1986), the deployment-of-attention task (DOAT; Gotlib et al., 1988), and the dotprobe task (MacLeod et al., 1986) The latter two have proven particularly useful because of their ability to distinguish between early and late stage attentional processing In the dot-probe task, which has been utilised in the present study, pairs of words or pictures (e.g., one negatively valenced word and one neutrally valenced word) are presented on screen (e.g., for 500 ms or 1000 ms) followed by a dot probe in the location of one of the two preceding stimuli Participants are required to press one of two buttons to indicate which side of the screen the probe appeared on Prior research has determined that participants’ reaction times are faster when the probe appears in the position of the attended-to stimulus Thus, attentional bias scores are calculated by subtracting probe detection speeds when the probe appears in the place of a negatively valenced stimulus from probe detection speeds when the probe appears in the place of a neutral stimulus Short stimulus durations (e.g., up to 500 ms) have been used to measure early stage orienting processes, whereas longer stimulus durations (e.g., 1000'/ ms) have been employed when later stage sustained attentional processing is being evaluated The DOAT works in a similar fashion, but uses a forced-choice format rather than relying on reaction times, asking participants to decide which of two coloured bars appeared first (in reality they both appear simultaneously, but it has been found that the attended-to bar seems to appear first) Researchers utilising relatively short stimulus durations (up to 500 ms post-stimulus onset) have generally failed to find consistent biases in depressed individuals’ attentional processing Mogg et al (1995) found ATTENTIONAL PROCESSING IN DYSPHORIA 791 no evidence of attentional biases in depressed individuals when the probe appeared 500 ms post-stimulus Bradley et al (1997) reported a similar lack of attentional bias, both at 14 ms and 500 ms post-stimulus, in naturally dysphoric individuals, and Mathews, Ridgeway, and Williamson (1996) presented data suggestive of biases only after 1000 ms post-stimulus The consistency of these null findings suggest that depressive disorders, unlike anxiety disorders (Broadbent & Broadbent, 1988; Mogg & Bradley, 1998), may not be characterised by hypervigilant orienting or ‘‘pre-attention’’ towards negative environmental stimuli (Bradley et al., 1997; Williams, Watts, MacLeod, & Mathews, 1997; see, however, Bradley, Mogg, & Williams, 1994, and Luecken, Tartaro, & Appelhans, 2004, for potentially contrary evidence demonstrating biases during subliminal presentations) In contrast, when longer stimulus durations have been utilised (e.g., 1000'/ ms), some evidence for depression-related attentional biases has been found Mogg et al (1995) found that clinical depression predicted negative attentional biases at 1500 ms post-stimulus, and Bradley et al (1997) and Mathews et al (1996) both found similar biases at 1000 ms post-stimulus In each of these studies, depressed individuals were found to manifest increased sustained attention towards the negative stimuli at these longer stimulus durations, despite not showing orienting mechanisms more characteristic of anxiety disorders This pattern of attentional deployment has led Williams et al (1997) to hypothesise that the locus of depressionrelated biases may rest in later stage, elaborative processes This interpretation remains consistent with a rich literature base demonstrating a high degree of ruminative behaviour in depressed (Beck, 1976; Harrington & Blankenship, 2002; Watkins & Brown, 2002) and dysphoric (Roberts, Gilboa, & Gotlib, 1998) individuals A number of additional studies have failed to demonstrate even later stage attentional biases in depression, however (e.g., Hill & Dutton, 1989; MacLeod & Chong, 1998; NeshatDoost, Moradi, Taghavi, Yule, & Dalgleish, 2000) and alternative hypotheses have been raised Murphy et al (1999) have, for instance, suggested that depressed individuals may have a more difficult time shifting attention away from negative stimuli once attention has been allocated, thus causing them to remain focused on the negative information after initial orientation in that direction (see also Ellenbogen, Schwartzman, Stewart, & Walker, 2002; Rinck & Becker, 2004) It should be noted that these two hypotheses are not necessarily mutually exclusive Difficulty disattending to negative stimuli could, for instance, play a role in the depressed individual’s increased ruminative behaviour To further cloud the issue, Gotlib et al (1988) have conversely suggested that it may be normal, rather than depressed, individuals who show biased 792 SHANE AND PETERSON attentional processing Utilising the DOAT, Gotlib et al (1988) found that whereas dysphoric individuals attended equally to negatively, positively and neutrally valenced words, non-dysphoric individuals attended more often to positive than to negative or neutral words Thus, whereas the nondysphoric participants were characterised by biased attention toward positive stimuli, the dysphoric participants showed a lack of such bias in their attentional processing This suggests that attentional processing biased toward positively valenced information may act as a protective factor against the onset of depression and dysphoria (see Taylor & Brown, 1988, who have explicitly suggested that the use of ‘‘positive illusions’’, which are ‘‘cognitive filters that preferentially screen out negative information’’, is commonplace, is a sign of mental health, and is negatively correlated with the onset of depressive symptomatology) Gotlib and colleagues have replicated their findings a number of times, in both clinically depressed patients (McCabe & Gotlib, 1995) and previously depressed patients (McCabe et al., 2000; see, however, Gotlib, Krasnoperova, Yue, & Joormann, 2004, for a recent non-replication using the dotprobe task) Only one study (McCabe & Toman, 2000) has, to date, varied the stimulus durations in the DOAT, however (750 ms has been standard), making determination of early and late stages of attentional processing within this task difficult Thus, the present set of studies was designed to further investigate the extent to which dysphoria is characterised by hypervigilance to negative information, hypovigilance to positive information, or a combination of both processing biases To this end, dysphoric and non-dysphoric individuals (as determined by Beck Depression Inventory scores [BDI]; Beck & Steer, 1993), were asked to perform a modified version of the dot-probe task, during which three different stimulus pairings were presented: positiveÁ neutral, negativeÁneutral, and neutral Áneutral (filler) Reaction times on positive Áneutral trials were used to index biases toward positive stimuli while reaction times on negative Áneutral trials were used to index biases toward negative stimuli Separation of positive and negative stimulus presentations was implemented quite purposely Although evaluating the nature of dysphorics’ attentional biases within situations characterised by the simultaneous presentation of both positive and negative stimuli may hold certain advantages (e.g., parsimony), such simultaneous presentation makes it impossible to determine the individual influence of each stimulus type In such mixed-trials, for instance, a bias away from the negative stimulus, or a bias toward the positive stimulus, would be difficult to differentiate through reaction-time measures A major purpose of the present study was to investigate the specific nature of positive and negative ATTENTIONAL PROCESSING IN DYSPHORIA 793 biases in dysphoria; thus, use of mixed positive Ánegative trials would not have served our purposes well.1 The present set of studies was also intended to investigate a number of specific issues regarding the nature of positive and negative biases First, we sought to determine whether these biases constitute global biases in attentional processing, as predicted by cognitive models based on schemas (Beck, 1976) or associative networks (Bower, 1981), or conversely are specific to either early or late stages of processing The time of onset of probes was thus varied across trials, and appeared either after a short duration (500 ms in study one, and 200 ms in study two) or a long duration (1500 ms in both studies) Evidence of attentional biases on the short-duration trials is often interpreted as indicative of biases in early stage attentional processing, whereas evidence of attentional biases on the long-duration trials is often interpreted as indicative of later stage attentional biases Second, we wanted to evaluate the possibility that the positive and negative biases may exist as independent markers of dysphoria Davidson, Pizzagalli, Nitschke, & Putnam (2002) have suggested that symptoms of depression related to positive and negative emotions may manifest independently, and may be underlain by distinct proximal causes By using separate trials to calculate positive and negative biases, it allows for the independence of these biases to be evaluated in several ways First, and most directly, the correlation between the positive and negative biases could be calculated A low correlation could suggest independence between attention allocated toward positive stimuli and attention allocated toward negative stimuli In addition, we were particularly interested in the possibility that dysphoric individuals may manifest both positive and negative biases, but that each bias may show a distinct temporal pattern A further possibility is that dysphoria may be characterised by a relative bias toward negative information (in relation to positive information), rather than an absolute bias toward either bias type (see Siegle, Ingram, & Matt, 2002, for the suggestion that dysphorics’ negative biases may come at the expense of attention allocated to more positive information) Thus, a final aim of the present research was to evaluate the predictive value of bias It is important to recognise the benefits and drawbacks of our approach of using positive (/ neutral and negative Áneutral trials, rather than integrated positive Ánegative trials As was pointed out by an anonymous reviewer, our use of separate positive Áneutral and negative Á neutral trials could serve to minimise a true correlation between positive and negative attentional biases While acknowledging this, given that not all situations need be characterised by the presence of both positive and negative stimuli, and because almost no situation (and perhaps no situation) could be characterised by the presence of only positive and negative stimuli, use of mixed positive-negative trials in the absence of any non-valent stimuli, could cause an equal enhancement of the true correlation Future research would benefit from a careful analysis of the benefits and drawbacks of each approach 794 SHANE AND PETERSON differentials (BD), which were calculated by subtracting participants’ biases to negative information from their biases to positive information By simultaneously taking into account the magnitude of both bias types, BDs may prove capable of identifying smaller effect sizes than either absolute bias Theoretically, if BDs show superior prediction than positive and negative biases it would imply that dysphoric individuals need not consistently show strong attentional bias away from negative stimuli, nor strong bias toward positive stimuli Rather, any combination of attentional processing resulting in a relative preference for negative stimuli may serve as the crucial characteristic underlying dysphoric processing STUDY ONE Method Participants Ninety-seven undergraduate psychology students at the University of Toronto volunteered for the study, in partial fulfilment of course credit Of these participants, 66 were women and 29 were men Their ages ranged from 18Á31 (M 0/20.43, SD 0/2.12) Assessment of dysphoria Participants completed the Beck Depression Inventory (BDI; Beck & Steer, 1993), which has been shown in numerous studies to be a reliable and valid measure of severity of depressive/dysphoric symptomatology in college (Oliver & Burkham, 1979), community, and patient samples (for a review see Beck, Steer, & Garbin, 1988) Those scoring and below on the BDI were classified as non-dysphoric, whereas those scoring 10 and above were classified as dysphoric By removing those scoring between and 9, potential difficulty regarding categorising ‘‘slightly dysphoric’’ individuals was avoided These cut-off scores are consistent with previous research utilising the BDI to establish research groups (e.g., Tennen, Hall, & Affleck, 1995), and is in line with Kendall, Hollon, Beck, Hammen, and Ingram’s (1987) recommendations regarding use of the BDI in non-clinical samples Only those participants who met these cutoffs (N 0/73) were included in the final analyses In addition to the BDI, participants also completed the short-form of the Taylor Manifest Anxiety Scale (TMAS; Bendig, 1956), because prior research has demonstrated depressive and anxious disorders to be highly comorbid The TMAS is a 20-item, true/false questionnaire that has been shown to correlate highly with other measures of trait anxiety and negative affectivity (Watson & Clark, 1984) Description of affective stimuli Stimuli were taken from the International Affective Picture System (Lang, Bradley, & Cuthbert, 1995), which ATTENTIONAL PROCESSING IN DYSPHORIA 795 contains normative ratings of affective valence for each picture on a 9-point scale from unpleasant (1) to pleasant (9) Forty positive, 40 negative and 120 neutral pictures were chosen, based largely on these valence ratings Negative pictures were selected in accordance with their relevance to sadness and threat, and included depictions of illness, disaster, drug injections and homelessness Positive pictures included puppies, sunsets, sweet desserts and flowers Neutral pictures were largely depictions of household items, such as lamps or chairs Each emotional picture (positive or negative) was paired with a neutral picture, matching as closely as possible within each pair for colour and shape of the focal object In total, there were 40 positiveÁ neutral, 40 negativeÁneutral, and 20 neutral Áneutral trials The latter trial type acted as filler, and was prepared so that emotionally valent stimuli were not displayed on each trial, and to decrease the opportunity for participants to determine the nature of the task Sexually explicit scenes from the IAPS were not included in the stimulus sets, as their influence on general arousal processes remains somewhat unclear Procedure After obtaining informed consent, participants completed the BDI and the short-form of the TMAS Participants next completed the dot-probe task (designed using E-Prime software; PSInet Corporation) on a Pentium II computer and a 15-inch monitor, in a quiet room in the laboratory The dot-probe task consisted of 10 practice, and 100 experimental trials (comprising the 40 positive Áneutral, 40 negativeÁneutral and 20 neutral Áneutral picture pairs) The practice trials were formed by using neutral Áneutral picture pairs not included in the experimental trials Each trial started with a central fixation cross for 500 ms, followed by a picture pair, with half the pairs being displayed for 500 ms and half for 1500 ms The positive or negative pictures appeared on the right or left side of the screen with equal frequency, as did the probe In addition, the probe appeared in the place of the emotionally valent pictures on half of the trials, and in the place of the neutral picture on half the trials For the neutral Áneutral trials, the probe appeared on the right or left an equal number of times The trials were presented in a different random order for each participant The dot probe was displayed immediately following the presentation of the picture pair, and participants were required to press one of two keys to indicate which side of the screen the probe appeared on The left index finger was used to hit the ‘‘Z’’ key for probes located on the left side, and the right index finger was used to press the ‘‘/’’ (slash) key for probes located on the right side Participants were informed to respond as quickly as they could, while remaining accurate The probe remained displayed until the participant responded, or for a maximum of 10 seconds The intertrial interval was 1000 ms Upon completion of the dot-probe task, participants were awarded course credit, debriefed, and allowed to leave 796 SHANE AND PETERSON Results Group characteristics Women (M 0/8.30, SD0/5.72) showed slightly higher BDI scores than men (M 0/7.92, SD 0/5.95), however, this difference did not prove significant, t(71) 0/0.07, p 0/.79 Subsequent data was thus collapsed across gender As expected, the dysphoric group (M0/14.10, SD 0/3.84) was characterised by significantly higher levels of dysphoria than the nondysphoric group (M0/4.05, SD 0/2.01; t(71) 0/ (/14.55, d 0/3.47, p B/.001) In addition, there was a trend toward the dysphoric group manifesting higher anxiety than the non-dysphoric group (dysphoric group: M 0/29.73, SD 0/4.18; non-dysphoric group: M 0/27.98, SD0/3.90; t(71) 0/1.84, d 0/0.43, p0/.07) Attentional biases Data from two participants (one dysphoric, one nondysphoric) were not included in the data set due to complications during the administration of the dot-probe task (the computer crashed in the middle of the task) Latency data from trials with errors (1.25% of all trials) were excluded from the analyses, as were latencies below 200 ms (2 trials) and greater than 700 ms (2.21% of all trials) after inspection of box and whisker plots These cutoff points, as well as the percentage of trials excluded based on those cut-offs, are comparable with that of previous research utilising the dot-probe paradigm (Bradley, Mogg, Falla, & Hamilton, 1998; Mogg, Millar, & Bradley, 2000) Mean RTs were collected for each group (see Table 1) and attentional bias scores were calculated for each trial type by subtracting the mean RTs when probes were in the same location as the emotional pictures from the mean RTs when they were in the opposite location (Bradley et al., 1998; Mogg et al., 2000) Thus, bias to negative stimuli was calculated from participant’s RTs on negative Áneutral trials, and bias to positive stimuli was calculated from participant’s RTs on positiveÁneutral trials Positive values of each bias score reflect attentional vigilance toward the valenced picture, whereas negative values reflect attentional avoidance of the valenced picture These two bias scores were found to be uncorrelated with one another, r0/.07, ns These attentional bias scores were entered into a )/2)/2 mixed-design ANOVA, with valence and duration as within-subject variables and dysphoria as a between-subject variable.2 A significant main effect of Before calculating attentional bias scores, we entered the raw RT data into a 2)/2 )/2)/2)/ ANOVA with valence (positive, negative), duration (500 ms, 1500 ms), picture location (left, right), and probe location (left, right) as within-subject variables, and dysphoria (high, low) as a between-subject variable Significant main effects of picture location, F (1, 70)0/7.97, p B/.01, duration, F (1, 70)0/178.25, p B/.001 and valence, F (1, 70)0/88.30, p B/.001 were identified Of particular note, the predicted four-way interaction of dysphoria )/ valence )/ picture location )/ probe location reached significance, F (1, 70)0/4.83, p 0/.03, which provided the basis for the calculation of the attentional bias scores used in the remainder of the analyses The five-way interaction involving duration did not reach significance, F (1, 70)0/1.46, p /.2 ATTENTIONAL PROCESSING IN DYSPHORIA 797 TABLE Mean response latencies to probes (in ms): Study one Picture valence Level of dysphoria Exposure duration Low 500 ms 1500 ms High 500 ms 1500 ms Picture location Probe location Left Left Right Right Left Left Right Right Left Right Left Right Left Right Left Right 433.31 432.85 449.50 446.89 400.80 393.23 399.62 407.61 (56.34) (61.07) (66.66) (59.14) (49.77) (46.17) (54.31) (50.15) 440.16 457.84 481.90 464.37 427.22 425.14 418.88 412.88 (62.14) (59.62) (63.58) (58.18) (56.67) (62.17) (61.41) (50.10) Left Left Right Right Left Left Right Right Left Right Left Right Left Right Left Right 429.65 444.54 448.82 438.66 393.43 399.10 399.47 402.68 (53.05) (67.89) (58.59) (63.27) (61.32) (62.74) (63.49) (57.22) 441.70 454.99 461.08 466.97 433.18 427.82 419.46 407.32 (67.51) (65.70) (69.51) (60.31) (67.68) (73.28) (60.96) (50.05) Positive Negative duration was revealed, F(1, 70) 0/8.59, h2 0/.11, p B/.01, as was a significant interaction between dysphoria and valence, F(1, 70) 0/4.11, h2 0/.06, pB/.05 The three-way dysphoria )/valence)/duration interaction did not reach significance, F(1, 70) 0/1.28, p /.20 We also performed a similar ANOVA including participants’ TMAS scores as a covariate to consider the possibility that the observed effects may be due to higher levels of anxiety in the dysphoric group In this analysis, the main effect of duration disappeared (p /.50), however the predicted dysphoria)/valence interaction remained significant, F(1, 69) 0/3.65, h2 0/.05, p0/.05 Furthermore, the anxiety)/valence interaction was nonsignificant, F(1, 69) 0/.19, p/.80.3 Dissection of the significant dysphoria )/valence interaction allowed for an initial investigation into the influence of positivity and negativity biases in dysphoria Figure 1a depicts this interaction in graphical form, with early and late biases collapsed As can be seen, non-dysphoric individuals showed a slight vigilance toward positive stimuli, whereas dysphoric individuals showed a more pronounced avoidance of positive stimuli Planned comparisons confirmed that these attentional biases differed significantly from Interpretation of these covariate analyses need be made with caution Miller and Chapman (2001) have pointed out that using a covariate that is highly correlated with the measure of interest may regress out substantial variance, and may leave a variable with little in common with the original construct With appropriate caution, we believe these covariate analyses remain useful, however, we also believe it important to note these issues of interpretation 798 SHANE AND PETERSON Dysphoric Nondysphoric (a) 10 –10 –20 –30 PB NB (b) 10 –10 –20 –30 PBE NBE (c) 20 10 –10 –20 PBL NBL Figure Level of bias toward/away from positive and negative stimuli on (a) all trials (b) shortduration trials, and (c) long-duration trials Note : PB 0/bias to positive stimuli; NB 0/bias to negative stimuli; PBE 0/bias to positive stimuli on early trials; NBE 0/bias to negative stimuli on early trials PBL 0/bias to positive stimuli on late trials; NBL 0/bias to negative stimuli on late trials ATTENTIONAL PROCESSING IN DYSPHORIA 803 Description of affective stimuli Words were utilised in study two rather than pictures because previous studies have utilised depression-specific words with considerable success (Bradley et al., 1997; Yovel & Mineka, 2005), and because creating a collection of depression-specific pictures seemed a somewhat daunting task Three word lists were thus developed: a positive word list (40 words, e.g., success, party, joy), a depression-related word list (40 words, e.g., gloomy, bleak, failure), and a neutral word list (100 words, e.g., range, vary, directly) Each word list was matched for both word length and word frequency (Kuchera & Francis, 1967), and three independent judges rated each word on 7-point Likert scales for its level of positivity, anxiety-relatedness, depression-relatedness, and arousability To this end, each depression-related word was rated as more related to depression than to anxiety In addition, the positivity and arousal ratings of the positive words were matched to the depression-relatedness and arousal ratings of the depression-related words Thus, differences in the degree of positivity/ depression-relatedness or the degree of arousal could not be used to provide alternative explanations of the findings Procedure After obtaining informed consent, participants were seated in front of a computer with a 15 inch monitor, and completed the dot-probe task The task was identical to that described in study one, with the following four exceptions First, words were used as stimuli, rather than pictures Second, each word pair was presented twice, once for each duration-type Of these, half of the word-pairs appeared for the first time on the short-duration trials, while the other half appeared for the first time on the long-duration trials Third, since each word pair was presented twice, the number of trials was doubled from that of study one Thus, 10 practice trials (utilising 20 unique neutralÁneutral word pairs) were followed by 200 experimental trials (comprising 80 positiveÁneutral, 80 negativeÁneutral and 40 neutral Áneutral word pairs) This was done in order to increase the number of observations used to calculate each bias score, and thus to increase the reliability of the task Fourth, the short-duration trials had a probe onset of 200 ms, rather than 500 ms as was utilised in study one The probe onset for long-duration trials remained at 1500 ms The final difference between the procedure in study two was that participants completed the BDI and TMAS after completing the dot-probe task, rather than before Mild concern was raised regarding the possibility that completing these scales before performing the dot-probe task may have led to subtle priming of attention toward the negative stimuli In order to ensure this did not influence the data for study two, we reversed the order of administration in the second study 804 SHANE AND PETERSON Results Group characteristics Once again, women (M 0/9.82, SD 0/9.21) showed slightly higher BDI scores than men (M 0/8.83, SD 0/8.88), however this difference was not significant, t(64) 0/.47, p0/.64 Thus, as in study one, subsequent analyses were conducted with data collapsed across gender As expected, the dysphoric group (M 0/19.15, SD 0/9.65) was characterised by significantly higher levels of dysphoria than the non-dysphoric group [M 0/ 3.38, SD 0/1.63], t(64) 0/ (/8.40, d 0/2.83, p B/.001, and also showed significantly higher levels of comorbid anxiety [dysphoric: M 0/31.37, SD 0/ 4.07; non-dysphoric: M 0/26.94, SD 0/3.77], t(64) 0/ (/4.47, d 0/.17, p B/.001 Attentional biases As in study one, latency data from trials with errors (B/1% of all trials) were excluded Similarly, after inspection via box and whisker plots, latencies below 200 ms or greater than 700 ms (1.73% of all trials) were also excluded from analyses These exclusion criteria remain consistent with those utilised in study one, as well as with the extant dotprobe literature (Bradley et al., 1998; Mogg et al., 2000) Mean RTs were collected for each group, and are displayed in Table As in study one, attentional bias scores were calculated for each trial type by subtracting the mean RTs when probes were in the same location as the emotional pictures from the mean RTs when they were in the opposite location (Bradley et al., 1998; Mogg et al., 2000) Thus, positive Áneutral trials were used to calculate biases toward/away from positive stimuli, and depressionÁneutral trials were used to calculate biases toward/away from depression-specific stimuli As in study one, these two biases were found to be largely uncorrelated, r0/.09, ns These attentional bias scores were entered into a )/2)/2 mixed-design ANOVA, with valence and duration as within-subject variables, and dysphoria as a between-subject variable.5 Neither the main effect of duration, F(1, 63) 0/0.12, p 0/.73, nor valence, F(1, 63) 0/1.83, p 0/.18, reached significance The predicted dysphoria )/ valence interaction was highly significant, F(1, 63) 0/7.49, h2 0/.11, p B/ 008 As in study one, the three-way interaction involving duration did not reach significance, F(1, 63) 0/0.003, p0/.96 A second similar ANOVA was Once again, before calculating attentional bias scores, we entered the raw RT data into a )/2)/2)/2)/2 ANOVA with valence (positive, negative), duration (200 ms, 1500 ms), picture location (left, right), and probe location (left, right) as within-subject variables, and dysphoria (high, low) as a between-subject variable Significant main effects of duration, F (1, 63)0/479.80, p B/.001, and valence, F (1, 63)0/15.01, p B/.001 were identified The predicted four-way interaction of dysphoria)/valence)/picture location )/ probe location reached significance, F (1, 63)0/9.93, p0/.002, which provided the basis for the calculation of the attentional bias scores used in the remainder of the analyses The five-way interaction involving duration did not reach significance, F (1, 63)0/1.66, p0/.20 ATTENTIONAL PROCESSING IN DYSPHORIA 805 TABLE Mean response latencies to probes (ms): Study two Picture valence Level of dysphoria Exposure duration Low 200 ms 1500 ms High 200 ms 1500 ms Picture location Probe location Left Left Right Right Left Left Right Right Left Right Left Right Left Right Left Right 439.94 450.67 448.01 439.14 387.41 386.17 399.81 400.56 (22.12) (37.79) (25.23) (31.26) (18.72) (28.09) (22.73) (36.70) 445.99 446.39 440.96 439.81 402.19 398.34 400.82 407.87 (23.92) (37.71) (18.08) (32.04) (40.30) (39.28) (38.28) (47.46) Left Left Right Right Left Left Right Right Left Right Left Right Left Right Left Right 438.27 431.11 434.45 443.15 387.13 371.43 386.95 398.24 (20.57) (34.17) (19.95) (40.00) (29.57) (32.01) (25.51) (26.88) 448.48 454.34 440.37 437.64 394.94 403.38 401.91 383.03 (20.59) (32.55) (22.26) (36.69) (27.89) (28.04) (33.26) (46.87) Positive Negative conducted with participants’ TMAS scores included as a covariate, and this analysis yielded a similar valence)/dysphoria interaction, F(1, 62) 0/8.96, h2 0/.13, p 0/.004 In addition, the valence)/anxiety interaction was nonsignificant, F(1, 62) 0/1.59, p0/.21 Thus, as in study one, the results appear to have been carried predominantly by level of dysphoria, rather than comorbid anxiety Figure 2a depicts the dysphoria )/valence interaction Non-dysphoric individuals showed a slight, although nonsignificant, vigilance toward the positive stimuli, t(38) 0/1.22, p0/.23, while dysphoric individuals showed a more pronounced avoidance of the positive stimuli, t(25) 0/ (/2.51, d0/.55, p 0/.02 Planned comparisons confirmed these attentional patterns to differ significantly from one another, t(63) 0/3.03, d 0/.77, p 0/.004 In addition, dysphoric participants manifested a bias toward the depression-specific stimuli, t(25) 0/2.17, d 0/.39, p 0/.04 Planned comparisons confirmed that the two groups’ dysphoric-specific bias scores differed significantly from each other, t(63) 0/ (/1.97, d 0/.51, pB/.05 Temporal differences Despite the nonsignificant three-way interaction involving duration, we once again examined the data for early and late duration trials separately (Figures 2b and 2c) These analyses revealed two separate effects First, the dysphoric group showed significant avoidance of the positive stimuli on short-duration trials, t(25) 0/ (/2.23, d0/.45, p0/.03, 806 SHANE AND PETERSON Dysphoric (a) 20 Nondysphoric 10 –10 –20 PB DSB (b) 20 10 –10 –20 PBE DSBE (c) 20 10 –10 –20 PBL DSBL Figure Level of bias toward/away from positive and depression-specific stimuli on (a) all trials (b) short-duration trials, and (c) long-duration trials Note : PB 0/Bias to positive stimuli; DSB 0/bias to depression-specific stimuli; PBE 0/bias to positive stimuli on early trials; DSBE 0/bias to depressionspecific stimuli on early trials; PBL 0/bias to positive stimuli on late trials; DSBL 0/bias to depressionspecific stimuli on late trials ATTENTIONAL PROCESSING IN DYSPHORIA 807 which differed from the non-dysphoric group, t(63) 0/3.15, d0/.76, p0/.002 Second, the dysphoric group showed significant vigilance toward dysphoricspecific stimuli on long-duration trials, t(25) 0/2.37, d0/.47, p0/.03, which differed from the non-dysphoric group, t(63) 0/ (/2.36, d0/.61, p0/.02 The non-dysphoric group showed no evidence of either bias at either stimulus duration Bias differentials Finally, bias difference (BD) scores were once again calculated for each participant by subtracting their bias toward positive stimuli from their bias toward depression-specific stimuli Analyses indicated that the non-dysphoric group was characterised by somewhat positive BDs (M 0/6.74, SD0/32.68), while the dysphoric group manifested highly negative BDs (M 0/ (/22.62, SD0/36.47) These BDs differed significantly from each other, t(63) 0/3.39, d0/.85, p B/.001, but only the dysphoric group’s negative BD differed significantly from zero [dysphoric: t(25) 0/3.16, d 0/.62, p 0/.004; non-dysphoric: t(38) 0/ (/1.29, p0/.20] Thus, similar to study one, dysphoric individuals manifested considerably more negative BDs than non-dysphoric individuals, a result that may have been further enhanced by the use of depression-specific content Regression analyses entering the absolute bias scores in block one, followed by BD in block two, indicated that BD significantly entered into the model in which depressionspecific bias was entered in block one (specific bias: b 0/ (/.206, p0/.26; BD: b 0/.355, p 0/.05), but failed to enter the model when positivity bias was entered in block one (see Table 4) It should be noted, however, that BD did knock the bias to positive stimuli out of the regression model when entered in block two However, neither predictor remained significant in this model Finally, early and late BDs were considered separately Non-dysphoric individuals showed neutral or positive BDs at both early and late stages of attentional processing (early: M 0/ (/.87, SD 0/49.26; late: M 0/2.63, SD 0/ 46.78), while dysphoric individuals showed negative BDs at both stages of processing (early: M0/ (/20.27, SD 0/46.89; late: M 0/ (/15.79, SD0/49.36) A repeated measures ANOVA with early and late BDs as within-subjects variables failed to reach significance, p 0/.95 Discussion The results of study two extend the findings from study one in a number of important ways First, whereas study one demonstrated that dysphoric individuals manifested a bias away from positive stimuli at 500 ms poststimulus onset, the results of the second study indicate that a similar bias away from positive stimuli can be identified as early as 200 ms post-stimulus onset Two-hundred milliseconds was chosen as the stimulus duration for the 808 SHANE AND PETERSON TABLE Regression models using absolute biases and bias differentials to predict BDI: Study two Standardised coefficient (b) p-value Model p-value Model Bias to positive stimuli Model Bias to positive stimuli Bias differential (/.263 (/.173 (/.121 018 296 465 018 Model Bias to depression-specific stimuli Model Bias to depression-specific stimuli Bias differential 109 (/.172 (/.378 337 296 024 337 Predictor 048 048 second study because research demonstrates that 200 Á300 ms is generally required in order to perform a voluntary disengagement and re-engagement of attentional gaze (Chun & Wolfe, 2001; Duncan et al., 1995) Thus, at 200 ms we can be relatively assured that the direction of the participants’ initial orienting in response to the dual-word display was being evaluated, and further that dysphoric individuals show initial orienting responses away from positive stimuli Research on orienting responses often claim that such responses occur automatically Although we are hesitant to characterise this dysphoric bias as automatic, the results of the present studies suggest that they are likely the result of particularly early stage processes This notion is consistent with a handful of recent studies which have also revealed evidence of early stage abnormalities in depressives’ attention to negative stimuli (Luecken et al., 2004; Lundh et al., 1999) Second, by using depression-specific stimuli in study two, in contrast to the more general category of ‘‘negatively valent’’ stimuli utilised in study one, a strong bias toward the depression-related stimuli was revealed within the dysphoric group A number of recent investigations have suggested that depressive and dysphoric individuals manifest a specific bias toward depression-specific information, which may not generalise to other negatively valent stimuli (Gotlib et al., 2004; Westra & Kuiper, 1997) The results of study two are consistent with these observations, and suggest that the inability to demonstrate a significant bias toward the negative stimuli in study one may have been due to the more heterogeneous collection of IAPS slides used The present study thus confirms the importance of utilising depression-specific stimuli when investigating processing biases in dysphoria, and provides further evidence to indicate that dysphoria is characterised by biased attention toward such depression-related stimuli The depression-specific nature of this bias is intriguing A number of cognitive and neural models have been proposed to explain how early, and perhaps pre-attentive, systems may preferentially process threat-related stimuli We are unaware of any similarly conceptualised system for the early ATTENTIONAL PROCESSING IN DYSPHORIA 809 preferential processing of depression-specific stimuli, however Thus, the depression-specific bias revealed in the present study is likely to have occurred as a result of later, more elaborative, stages of stimulus processing Indeed, despite the lack of an interaction with duration, it should be noted that the dysphoric participants’ avoidant biases to depression-specific stimuli were only seen during long-duration trials, ostensibly evaluating late-stage processing During short-duration trials, in contrast, no such depressionspecific bias was revealed This is consistent with Williams et al.’s (1997) characterisation of depressive biases as specific to more elaborative processing, and adds to a growing body of support for this characterisation GENERAL DISCUSSION Taken together, the results of both studies demonstrate that there are significant differences between the attentional patterns of dysphoric and non-dysphoric individuals Non-dysphoric individuals showed relatively unbiased processing of positive stimuli, and may have also shown a bias away from negatively valent information In contrast, dysphoric individuals showed substantial biases: away from positive stimuli and toward depression-related stimuli The bias toward depression-specific stimuli is consistent with the extant literature (Bradley et al., 1997; Williams et al., 1997; Mogg et al., 1995; Williams et al., 1997); the bias away from positive information has not generally been reported It should be noted that findings reported with the DOAT have suggested that a lack of bias toward positive information may underlie depressive processing (Gotlib et al., 1988; Gotlib & Cane, 1987) The present results differ from the DOAT results in that they indicated that group differences were driven by active avoidance by the dysphoric individuals rather than an enhanced bias toward such information in the non-dysphoric group Nonetheless, the results of both investigations converge in demonstrating that dysphoric individuals may process positive information to a lesser extent than non-dysphoric individuals, and raise the possibility that the present results, and those of Gotlib and colleagues (Gotlib et al., 1988; McCabe & Gotlib, 1995; McCabe et al., 2000), are indicative of a similar underlying process Despite revealing both of these biases in dysphoric individuals, we not want the fundamental message taken from these studies to be that individuals suffering from depressive disorders must exhibit both types of bias Rather, we believe a commonality of both biases is their capacity to promote a condition in which a greater relative proportion of negative to positive information is consistently allocated processing resources (see Siegle et al., 2002, for a similar argument) That is, both a bias toward negative information, whereby attention is preferentially allocated toward negative, 810 SHANE AND PETERSON rather than neutral, stimuli, and a bias toward positive information, whereby attention is preferentially allocated toward positive, rather than neutral, stimuli, could serve as a precursor for processing more negative than positive information Furthermore, it may be this relative bias in attentional allocation, rather than either absolute bias, which is most capable of characterising the nature of attentional processing in depressive disorders Consistent with this notion, in both studies, BD scores served as an equal or superior predictor of dysphoria within non-clinical undergraduate samples, compared to either absolute bias One advantage of this line of reasoning is its ability to account for inconsistency in the extant literature, wherein some studies have identified processing differences to negative or depression-specific information (Bradley et al., 1997; Mogg et al., 1995), and others have identified processing differences to positive information (Gotlib & Cane, 1987; Gotlib et al., 1988) If participants can show one or the other processing bias, evaluation of only one bias may result in low power to identify all dysphoric individuals To this end, future research would well to ensure that attentional patterns to both positive and negative stimuli are evaluated simultaneously, so that consideration of their relative influences can be further evaluated BDs may prove a useful metric in this regard While attractive in its parsimony and potentially useful as a high-level metric, we recognise that characterising dysphoric processing through a single BD score carries the significant disadvantage of precluding consideration of the potential differences underlying the two bias types Thus, although we hope the BD measure proves useful, we believe it prudent to also warn against ignoring the individual biases in favour of this higherorder construct One critical finding from the present studies involves the fact that the level of bias to positive information was uncorrelated with the level of bias to negative information Furthermore, exploratory analyses suggested that the dysphoric individual’s bias toward positive and depression-specific information may have different temporal patterns, whereby their avoidance of positive stimuli appeared more robust at early stages of processing, while their vigilant bias toward dysphoric-specific information only appeared on long-duration trials Although the reliability of these measures may preclude firm conclusions, these results suggest the possibility that the two biases may serve as separate indicators of dysphoria, and may occur as a result of distinct underlying mechanisms The utility of considering these biases as indicative of separate indicators of dysphoric and depressive disorders becomes critical when considering the underlying systems involved in the control of these processes Davidson et al (2002, p 3) have argued that: ‘‘depression may arise from a multitude of proximal causes and whereas the broad symptoms share a certain similarity, the underlying mechanisms may differ’’ Following this line of reasoning, it ATTENTIONAL PROCESSING IN DYSPHORIA 811 is intriguing to consider the possibility that dysphoric individuals who manifest biases away from positive information may have substantively different underlying causes for their dysphoria than dysphoric individuals who manifest biases toward negative/depression-specific information Consistent with this notion are a variety of well-established models of goal-directed behaviour (e.g., Gorenstein & Newman, 1980; Gray, 1982; Gray & McNaughton, 2000) that implicate two mutually inhibitory arousal systems In Gray’s model, for instance, the behavioural activation system (BAS) initiates approach behaviour to cues for reward or active avoidance, and is associated with positive emotionality and attentional vigilance The behavioural inhibition system (BIS), in contrast, inhibits behaviour in response to cues for novel or punishing stimuli, and is associated with negative emotionality and attentional avoidance Thus, some depressed individuals *particularly those with pervasive symptoms of negative affect and anxiety as part of their symptom cluster *may manifest increased attention toward negative information as a result of an over-active BIS Other depressed individuals *particularly those who exhibit a pervasive lack of positive affect and goal-directed motivation *may manifest decreased attention toward positive information as a result of an underactive BAS Davidson et al (2002) have made a similar distinction between depressive symptoms due to enhanced negative, or reduced positive, emotions, and have further suggested that these two depressive subtypes may have separate neural signatures These authors discuss the involvement of a multiplicity of brain structures, and the reader is directed to their excellent review for a full description of possible neural systems involved in depressive disorders (see also Surguladze et al., 2005, for demonstration of different neural patterns during the processing of happy and sad facial expressions in depression) In short, they argue that different regions of the prefrontal cortex (PFC), which plays a crucial role in the facilitation of task-appropriate responses in the face of competition, may be differentially involved in each depressive subtype Specifically, hypoactivation of left-sided PFC regions, particularly involved in approach-related appetitive goals, may result in deficits in motivation and the attainment of positive affect, whereas hyperactivation of right-sided PFC regions, particularly involved in the maintenance of goals that require behavioural inhibition, may lead to excessive behavioural withdrawal and anxiety The PFC has extensive connections to the anterior cingulate cortex and the amygdala, both of which have recently been implicated in directing attentional resources to affectively salient stimuli (Davis & Whalen, 2001; Devinsky, Morrell, & Vogt, 1995; Holland, JungSoo, & Gallagher, 2000) Thus, it may be that excessive right-sided PFC activity could lead to increased attention to negative information, and 812 SHANE AND PETERSON attenuated left-sided PFC activity could lead to decreased attention to positive information CONCLUSION The present set of studies confirms that dysphoria is characterised by attentional patterns that differentiate them from non-dysphoric individuals Most robustly, dysphoric individuals showed attentional biases toward depression-specific stimuli In addition, evidence suggestive of an additional bias away from positive stimuli was garnered from both studies These two biases were uncorrelated in both studies, and exploratory analyses suggested that they may have distinct temporal patterns These findings suggest that both biases may occur as a result of separate etiological mechanisms Manuscript received August 2005 Revised manuscript received June 2006 Manuscript accepted June 2006 REFERENCES Beck, A T (1976) Cognitive therapy and the emotional disorders Oxford, UK: International Universities Press Beck, A T., & Steer, R A (1993) Manual for the Revised Beck Depression Inventory San Antonio, TX: Psychological Corporation Beck, A T., Steer, R A., & Garbin, M G (1988) Psychometric properties of the Beck Depression Inventory: Twenty-five years of evaluation Clinical Psychology Review, 8, 77 Á 100 Bendig, A W (1956) The development of a short form of the Manifest Anxiety Scale Educational & Psychological Measurement, 16, 516 Á523 Bower, G H (1981) Mood and memory American Psychologist, 32, 129 Á148 Bradley, B P., Mogg, K., Falla, S J., & Hamilton, L R (1998) Attentional bias for threatening facial expressions in anxiety: Manipulation of stimulus duration Cognition & Emotion, 12, 737 Á753 Bradley, B P., Mogg, K., & Lee, M (1997) Attentional biases for negative information in induced and naturally occurring dysphoria Behavioural Research & Therapy, 35, 911 Á927 Bradley, B P., Mogg, K., & Williams, R (1994) Implicit and explicit memory for emotional information in non-clinical subjects Behavioural Research and Therapy, 32, 65 Á78 Broadbent, D., & Broadbent, M (1988) Anxiety and attentional bias: State and trait Cognition & Emotion, 2, 165 Á183 Chun, M M., & Wolfe, J M (2001) Visual attention In B E Goldstein (Ed.), Blackwell handbook of experimental psychology (pp 272 Á310) Malden, MA: Blackwell Publishers Davidson, R J., Pizzagalli, D., Nitschke, J B., & Putnam, K (2002) Depression: Perspectives from affective neuroscience Annual Review of Psychology, 53, 545 Á574 Davis, M., & Whalen, P J (2001) The amygdala: Vigilance and emotion Molecular Psychiatry, 6, 13 Á34 ATTENTIONAL PROCESSING IN DYSPHORIA 813 Devinsky, O., Morrell, M J., & Vogt, B A (1995) Contributions of anterior cingulate cortex to behavior Brain, 118, 279 Á306 Duncan, J., Ward, R., & Shapiro, K L (1995) Direct measure of attentional dwell time in human vision Nature, 369, 313 Á315 Ellenbogen, M A., Schwartzman, A E., Stewart, J., & Walker, C D (2002) Stress and selective attention: The interplay of mood, cortisol levels, and emotional information processing Psychophysiology, 39, 723 Á732 Gorenstein, E E., & Newman, J P (1980) Disinhibitory psychopathology: A new perspective and a model for research Psychological Review, 87, 301 Á315 Gotlib, I H., & Cane, D B (1987) Construct accessibility and clinical depression: A longitudinal investigation Journal of Abnormal Psychology, 96, 199 Á204 Gotlib, I H., Krasnoperova, E., Yue, D N., & Joormann, J (2004) Attention biases for negative interpersonal stimuli in clinical depression Journal of Abnormal Psychology, 113, 127 Á135 Gotlib, I H., McLachlan, A L., & Katz, A N (1988) Biases in visual attention in depressed and nondepressed individuals Cognition & Emotion, 2, 185 Á200 Gray, J A (1982) The neuropsychology of anxiety: An enquiry into the functions of the septohippocampal system New York: Clarendon Press/Oxford University Press Gray, J A., & McNaughton, N (2000) The neuropsychology of anxiety: An enquiry into the functions of the septo-hippocampal system (2nd ed.) New York: Oxford University Press Harrington, J A., & Blankenship, V (2002) Ruminative thoughts and their relation to depression and anxiety Journal of Applied Social Psychology, 32, 465 Á485 Hill, A B., & Dutton, F (1989) Depression and selective attention to self-esteem threatening words Personality & Individual Differences, 10, 915 Á917 Holland, P C., Jung-Soo, H., & Gallagher, M (2000) Lesions of the amygdala central nucleus alter performance on a selective attention task Journal of Neuroscience, 20, 6701 Á6706 Ingram, R E., Miranda, J., & Segal, Z V (1998) Cognitive vulnerability to depression New York: Guilford Press Ingram, R E., & Ritter, J (2000) Vulnerability to depression: Cognitive reactivity and parental bonding in high-risk individuals Journal of Abnormal Psychology, 109, 588 Á596 Kendall, P C., Hollon, S D., Beck, A T., Hammen, C L., & Ingram, R E (1987) Issues and recommendations regarding use of the Beck Depression Inventory Cognitive Therapy & Research, 11, 289 Á299 Kuchera, H., & Francis, W (1967) Computational analysis of present-day American English Providence, RI: Brown University Press LaBerge, D (1995) Attentional processing: The brain’s art of mindfulness In Perspectives in cognitive neuroscience Cambridge, MA: Harvard University Press Lang, P J., Bradley, M M., & Cuthbert, B N (1995) International Affective Picture System (IAPS): Affective ratings of pictures and instruction manual (Tech Rep No A-6) Gainesville, FL: University of Florida Luecken, L J., Tartaro, J., & Appelhans, B (2004) Strategic coping responses and attentional biases Cognitive Therapy and Research, 28, 23 Á37 Lundh, L., Wikstrom, J., Westerlund, J., & Ost, L (1999) Preattentive bias for emotional information in panic disorder with agoraphobia Journal of Abnormal Psychology, 108, 222 Á 232 MacLeod, C., & Chong, J (1998) Emotion-congruent processing biases in selective attention, explicit memory and implicit memory Unpublished manuscript MacLeod, C., Mathews, A., & Tata, P (1986) Attentional bias in emotional disorders Journal of Abnormal Psychology, 95, 15 Á20 Mathews, A., & MacLeod, C (1986) Discrimination of threat cues without awareness in anxiety states Journal of Abnormal Psychology, 95, 131 Á138 814 SHANE AND PETERSON Mathews, A., Ridgeway, V., & Williamson, D A (1996) Evidence for attention to threatening stimuli in depression Behaviour Research & Therapy, 34, 695 Á705 McCabe, S B., & Gotlib, I H (1995) Selective attention and clinical depression: Performance on a deployment-of-attention task Journal of Abnormal Psychology, 104, 241 Á245 McCabe, S B., Gotlib, I H., & Martin, R A (2000) Cognitive vulnerability for depression: Deployment of attention as a function of history of depression and current mood state Cognitive Therapy & Research, 24, 427 Á444 McCabe, S B., & Toman, P E (2000) Stimulus exposure duration in a deployment-of-attention task: Effects on dysphoric, recently dysphoric, and non-dysphoric individuals Cognition & Emotion, 14, 125 Á152 Miller, G A., & Chapman, J P (2001) Misunderstanding analysis of covariance Journal of Abnormal Psychology, 110, 40 Á48 Mogg, K., & Bradley, P (1998) A cognitive-motivational analysis of anxiety Behaviour Research & Therapy, 36, 809 Á848 Mogg, K., Bradley, B P., & Williams, R (1995) Attentional bias in anxiety and depression: The role of awareness British Journal of Clinical Psychology, 34, 17 Á36 Mogg, K., Millar, N., & Bradley, B P (2000) Biases in eye movements to threatening facial expressions in generalized anxiety disorder and depressive disorders Journal of Abnormal Psychology, 109, 695 Á704 Murphy, F C., Sahakian, B J., Rubinsztein, J S., Michael, A., Rogers, R D., Robbins, T W., et al (1999) Emotional bias and inhibitory control processes in mania and depression Psychological Medicine, 29, 1307 Á1321 Neshat-Doost, H T., Moradi, A R., Taghavi, M R., Yule, W., & Dalgleish, T (2000) Lack of attentional bias for emotional information in clinically depressed children and adolescents on the dot probe task Journal of Child Psychology & Psychiatry & Allied Disciplines, 41, 363 Á368 Oliver, J M., & Burkham, R (1979) Depression in university students: Duration, relation to calendar time, prevalence and demographic correlates Journal of Abnormal Psychology, 88, 667 Á670 Posner, M I., & Peterson, S F (1990) The attention system of the human brain Annual Review of Neuroscience, 13, 25 Á42 Rinck, M., & Becker, E S (2004) A comparison of attentional biases and memory biases in women with social phobia and major depression Journal of Abnormal Psychology, 114, 62 Á 74 Roberts, J E., Gilboa, E., & Gotlib, I H (1998) Ruminative response style and vulnerability to episodes of dysphoria: Gender, neuroticism, and episode duration Cognitive Therapy & Research, 22, 401 Á423 Siegle, G J., Ingram, R E., & Matt, G E (2002) Affective interference: An explanation for negative attention biases in dysphoria? Cognitive Therapy & Research, 26, 73 Á87 Surguladze, S., Brammer, M J., Keedwell, P., Giampietro, V., Young, A W., Travis, M J., et al (2005) A differential pattern of neural response toward sad versus happy facial expressions in major depressive disorder Biological Psychiatry, 57, 201 Á209 Suslow, T., Junghanns, K., & Arolt, V (2001) Detection of facial expressions of emotions in depression Perceptual and Motor Skills, 92, 857 Á868 Taylor, S E., & Brown, J D (1988) Illusion and well-being: A social psychological perspective on mental health Psychological Bulletin, 103, 193 Á210 Tennen, H., Hall, J A., & Affleck, G (1995) Depression research methodologies in the Journal of Personality and Social Psychology: A review and critique Journal of Personality & Social Psychology, 68, 870 Á884 Watkins, E., & Brown, R G (2002) Rumination and executive function in depression: An experimental study Journal of Neurology, Neurosurgery & Psychiatry, 72, 400 Á402 ATTENTIONAL PROCESSING IN DYSPHORIA 815 Watson, D., & Clark, L A (1984) Negative affectivity: The disposition to experience aversive emotional states Psychological Bulletin, 96, 465 Á490 Westra, H A., & Kuiper, N A (1997) Cognitive content specificity in selective attention across four domains of maladjustment Behaviour Research & Therapy, 35, 349 Á365 Williams, J M G., Watts, F N., MacLeod, C., & Mathews, A (1997) Cognitive psychology and the emotional disorders (2nd ed) New York: Wiley Yovel, I., & Mineka, S (2005) Emotion-congruent attentional biases: The perspective of hierarchical models of emotional disorders Personality & Individual Differences, 38, 785 Á 795 View publication stats ...790 SHANE AND PETERSON rumination (later stage attentional processing) on such negative information (see Posner & Peterson, 1990, or LaBerge, 1995, for a discussion of early and late stage attentional. .. significant in this model Finally, early and late BDs were considered separately Non-dysphoric individuals showed neutral or positive BDs at both early and late stages of attentional processing (early: ... symptoms of depression related to positive and negative emotions may manifest independently, and may be underlain by distinct proximal causes By using separate trials to calculate positive and negative