DOI: 10.1111/phin.12189 Philosophical Investigations 41:2 April 2018 ISSN 0190-0536 Picturing Primates and Looking at Monkeys: Why 21st Century Primatology Needs Wittgenstein Louise Barrett, University of Lethbridge Abstract The Social Intelligence or Social Brain Hypothesis is an influential theory that aims to explain the evolution of brain size and cognitive complexity among the primates This has shaped work in both primate behavioural ecology and comparative psychology in deep and far-reaching ways Yet, it not only perpetuates many of the conceptual confusions that have plagued psychology since its inception, but amplifies them, generating an overly intellectual view of what it means to be a competent and successful social primate Here, I present an analysis of the Social Intelligence/Brain hypothesis highlighting how its anthropocentric origins have led us to be held captive by a picture of what social life involves and the kind of mind needed to navigate the social landscape I go on to consider how experimental work in this vein either does not test what it claims to be testing, or introduces impossible problems regarding animal minds that cannot be solved, but only dissolved What we need, in other words, is the application of “Wittgenstein’s razor” and the reinvention of primatology along his enactivist lines I Introduction Wittgenstein famously pointed out that the barrenness of psychology could not be accounted for by its being a young science The problem was a deep conceptual confusion, not a lack of experimental evidence for its claims.1 Although Wittgenstein identified and remedied these confusions, sadly the Many thanks to Daniele Moyal-Sharrock for the invitation to speak at the 10th British Wittgenstein Conference, where I presented a version of this paper Thanks also to Michael Bavidge, Michel Bitbol, Robert Chapman, Ian Ground, Peter Hacker, Constantine Sandis and Chon Tejedor for interesting discussions on these and related issues My work is supported by The Natural Sciences and Engineering Research Council of Canada Discovery Grant and Canada Research Chair programs Wittgenstein (1953) © 2018 John Wiley & Sons Ltd 162 Philosophical Investigations cure did not take The same old confusions persist, with researchers continuing to insist that all we need are more data and better tests Some of these confusions have come to infect how we conceive of minds besides our own, particularly those of our closest living relatives This, in turn, influences the ways in which we think about our ties to other species, and how we reconstruct human evolutionary history We thus need Wittgenstein more than ever, not only to improve the quality of scientific theory and practice, but also because, in the words of anthropologist, Ashley Montagu, “it is essential that we not base our image of ourselves on false foundations What is involved here is not simply the understanding of human nature, but also the image of humanity that grows out of that understanding.” In what follows, I present an investigation of the “social intelligence” or “social brain” hypothesis2 – an influential theory that aims to explain the evolution of brain size and cognitive complexity among the primates This has shaped work in both primate behavioural ecology and comparative psychology in deep and far-reaching ways Yet, it not only perpetuates many of the conceptual confusions that have plagued psychology since its inception, but amplifies them, generating an overly intellectual view of what it means to be a competent and successful social primate What we need is the application of “Wittgenstein’s razor”3 to help rid us of the impossible problems of primatology Before I begin, I should offer a disclaimer I came to Wittgenstein late, and also backwards I was once a huge advocate of the ideas I now criticize, embracing cognivitism and computation, “theory of mind”, and the “language of thought” Even once I began to have my doubts about the application of these ideas to humans and other animals, turning instead to the fields of embodied and enactive cognition, I still referred to encoding and decoding, and representations and inferences with respect to what brains were up to, as well as embracing reductionist arguments for mirror neutrons as the basis for empathy and intersubjectivity.4 As a result, I have no doubt contributed my own confusions It was only once I had spent more time reading and writing about non-primates that I found my position had shifted completely towards that of radical embodied cognitive science and enactivism – not least because they provide a way to avoid the anthropocentrism inherent to the cognitivist position.5 It was at this point that I met Daniele Moyal-Sharrock, and was introduced to the e.g., Humphrey (1976), Dunbar (1998) Moyal-Sharrock (2013) Barrett et al (2001, 2003), Barrett and Henzi (2005), Barrett et al (2007), Barrett (2010) Barrett (2011, 2012), Barrett et al (2012) © 2018 John Wiley & Sons Ltd Louise Barrett 163 work of Wittgenstein (and to Wittgenstein as the original enactivist, no less) and, through this, came to develop a completely different view of mental life.6 At the same time, by coming to it late, my incorporation of Wittgenstein’s philosophy is still rudimentary So I not want to suggest that I have seen things more clearly than others, and been less prone to error and confusion – I have been as confused as anyone and probably still am If anything, I am more like a reformed smoker, who regrets indulging in such an unhealthy habit, and would like to persuade others to not make the same mistake What is clear to me is that understanding more about Wittgenstein’s philosophy, and accepting his cure, will pay enormous dividends for those working in the fields of comparative cognition and cognitive ethology Here, I offer some pointers to how and why that is the case II Primates, Brains and Evolution: A Brief History of the Social Intelligence Hypothesis Over the last 50 years, there has been a growing scientific consensus that social life has exerted a unique selection pressure on members of the primate order The particular demands of social life are argued to explain both the evolution of large brain size and a suite of cognitive capacities that make it possible to engage with other social beings and interpret their behaviour.7 After all, or so the argument goes, the ecological demands that primates face are not excessive in comparison to those of other species: getting enough to eat, and avoiding being eaten, are also feats accomplished by species with far less in the way of neural tissue The intense sociality of the primates, however, particularly the anthropoid monkeys and apes, seems to mark them out as different from other species It therefore seems reasonable to suppose that these traits – large brains and intense sociality – are linked One of the first researchers to point this out was Alison Jolly, who argued that primate social life “preceded the growth of primate intelligence, made it possible, and determined its nature”.8 This was followed in 1976 with a now seminal paper by Nicholas Humphrey, who (independently of Jolly) advanced an equivalent argument, based on his own experiences with wild gorillas and captive macaques.9 Humphrey argued Barrett (2015a,b, 2016.) see, for example, Dunbar and Shultz (2017) for a recent review Jolly (1966: 506) Humphrey (1976) © 2018 John Wiley & Sons Ltd 164 Philosophical Investigations that obligate sociality generated unavoidable competition for resources and, this in turn, placed a premium on the ability to predict how other animals were likely to act in order to anticipate, ameliorate or even avoid such competition altogether Thus, in order to respond to the dynamic contingencies generated by other animate beings, primates required a specific psychological insight into the minds and actions of others Humphrey thus made the case for primates as ‘social gamesmen’, rather like human chess-players: they needed to be “calculating beings”, capable of a “special form of forward planning” In such a situation, Humphrey argued, “‘social skill’ goes hand in hand with intellect”.10 Humphrey characterized this kind of intellect as “creative” in contrast to the kind of “practical” intelligence needed to forage efficiently and successfully Indeed, he argued that, provided the right kind of social background was in place, the practical skills needed to subsist effectively could be learnt by simple associative processes In this way, the large brains observed among the primates became equated with a particular kind of hypothesized cognitive skill: the ability to make a prospective assessment of another’s future actions based on inferences about their mental processes This idea of primates as “calculating beings” gained even greater prominence with the publication of the book “Machiavellian Intelligence”,11 in which Humphrey’s hypothesis was brought together with observations on the sophisticated social behaviour of primates (such as “tactical deception” and “alliances” in contests), and experimental evidence relating to so-called “theory of mind” (ToM) – the ability to infer and attribute mental states to others.12 The links to human evolution were made more explicit here, with the new theory contrasted with the conventional idea that the evolution and invention of tool use during the Plio-Pleistocene could explain humans’ greater cognitive sophistication The Machiavellian intelligence hypothesis suggested that complex human cognition might have a much longer evolutionary history that could be traced through the living primates, rather than our fossil ancestors alone.13 At the beginning of the 1990s, more targeted empirical tests of the theory began to appear Robin Dunbar, for example, found a positive correlation between neocortex ratio14 and group size across the anthropoid primates, but no such relationship with ecological variables.15 Group size was considered to be a crude, but relevant, measure of social 10 Humphrey (1976: 309) 11 Byrne and Whiten (1989) 12 Premack and Woodruff (1978), Premack (1989) 13 Byrne (1997) 14 The ratio of the size of the cerebral lobes – the most recently evolved parts of the mammalian brain – to the rest of the brain 15 Dunbar (1992, 1995) © 2018 John Wiley & Sons Ltd Louise Barrett 165 complexity, on the assumption that “information-processing demands can be expected to increase as the number of relationships increases”.16 Further empirical studies reinforced the association between social life and brain size by correlating neocortex measures with the occurrence of social behaviours like promiscuous mating, grooming clique size and rates of deception.17 This vindicated the use of social group size as a measure of social complexity by linking brain size to particular kinds of behaviour Together, these findings were taken as evidence that the ability to represent and manipulate specific kinds of information about social relationships (as opposed to, say, improved memory capacities) had both selected for increased brain size, and then placed limits on the size of group that a given species was able to sustain Thus, “constraints on group size arise from the information-processing capacity of the primate brain, and .the neocortex plays a major role in this”.18 Further, the form of social intelligence indexed by enlarged neocortex size “principally focuses on the ability to use knowledge about other individuals’ behaviour – and perhaps mind-states – to predict and manipulate those individuals’ behaviour”.19 III From Theory to Application (and Many Untested Assumptions) One thing that is notable about this shift to empirical testing is how the social intelligence hypothesis became reduced to the social brain hypothesis Humphrey refers solely to “intellect” and “creative intelligence”, and makes no reference to brain size as such With the move to empirical testing, brain size was substituted as evidence of Humphrey’s hypothesized “creative intelligence” One reason for this is pragmatic: there was large existing database covering the entire primate order, whereas comparable 16 Dunbar (1998: 179-80) A parallel series of studies by Barton (1998, 2004; Barton et al 1995) refined these analyses, by identifying the specific parts of the brain that showed the greatest expansion, demonstrating, among other relationships, that the parvocellular layer of the lateral geniculate nucleus correlated with group size, suggesting a primary role for visual signalling in driving brain size evolution In addition, Barton and Venditti (2014) have shown that, among the apes, it is the cerebellum rather than the neocortex that has undergone an explosive increase in size This has been argued to support the idea that it was ‘technical intelligence’ (i.e., the ability to manipulate and plan sequences of actions) as opposed to social intelligence that accounts for ape cognitive abilities, relative to those of the monkeys Recently, new empirical analyses argue that ecological variables are more important than group size (DeCasien et al 2017; Powell et al 2017), and also that variability across datasets raise doubts about inferring cognitive selection pressures from behavioural correlates of brain size (Powell et al 2017) 17 Pawlowski et al (1998), Kudo and Dunbar (2001), Byrne and Corp (2004) 18 Dunbar (1998: 184) 19 Dunbar (2003: 167) © 2018 John Wiley & Sons Ltd 166 Philosophical Investigations data on cognitive abilities were much more sparse The use of brain size adds a further layer of assumptions to the theory, however Not only does it assume that brain size can provide an accurate index of an animal’s cognitive abilities—often referred to as “computing power” – but it also assumes that the brain alone is responsible for the production of intelligent behaviour Thus, this shift to thinking in terms of the social brain, rather than social intelligence, firmly established the hypothesis as strongly cognitivist, with a strong emphasis on the computational capacity of the brain The most important thing to note, however, is that brain size was not treated simply as an index of cognitive sophistication, but taken as evidence for the specific cognitive mechanisms argued to underpin sophisticated social behaviour That is, social life was argued to be complex because it required animals to internally represent and manipulate information about others, predict their future behaviour, and act to encourage or thwart this course of action to one’s own advantage, and this selected for large brain size The reasoning here, however, runs from large brains to the kinds of complex processing that large brains would afford in a social context, rather than vice versa No empirical evidence was presented for the proposed cognitive mechanisms themselves The same is true for the studies that correlated brain size with particular forms of social behaviour – the actual cognitive mechanisms argued to mediate between brain and behaviour were not actually specified There was, therefore, an interesting slippage between levels of explanation While the correlation between brain size and group size across the primate order can be seen as a valid test of the evolutionary argument – that social life, rather than ecology, exerted a pressure for larger brains – this empirical result was also taken as evidence for the hypothesized (but poorly specified) cognitive mechanisms operating at the proximate level Another example of this kind of backwards reasoning can be found in Dunbar’s discussion of a “grade shift” across the prosimians, monkeys and apes in the neocortex size-group size relationship (i.e., a difference in the relative elevation of the slopes for the three groups in a linear regression analysis) That is, for a given group size, apes had larger brains than monkeys who, in turn, had larger brains than prosimians Dunbar argued that “[i]t is as if apes require more computing power to manage the same number of relationships that monkeys do, and monkeys in turn require more than prosimians This gradation corresponds closely to the perceived scaling of social complexity.”20 This needs some unpacking because group size (as a measure of social complexity) was the variable 20 Dunbar (1998: 185) © 2018 John Wiley & Sons Ltd Louise Barrett 167 used to test the hypothesis that social complexity should correlate positively to brain size To then argue that apes living in groups of a given size require more ‘computing power’ than either monkeys or prosimians living in groups of equivalent size not only undermines the reasoning with respect to group size being used to represent social complexity, but it seems to be based on the a priori assumption that, as the apes are the largest-brained, they will inevitably have more complex societies (this is the ‘perceived scaling of social complexity’) Here, again, the reasoning runs backwards from the existence of large brains to the presumption of complex sociality This reasoning is then used to offer a post hoc explanation of why results that seemingly go against prediction are, in fact, exactly what one would expect IV Assumptions and Anthropocentrism One reason why these assumptions and inferences have been seen as reasonable must surely lie in the anthropocentric focus of Humphreys’ original theory, and its extension to the Machiavellian Intelligence hypothesis Both of these make clear that explaining the evolutionary origins of our own intellectual powers was an integral part of the project Although this is perfectly reasonable, given that we are members of the primate order, knowledge of our own capacities and skills (or at least our current ideas of what these are) inevitably colours the evolutionary hypotheses put forward to explain how those skills arose Indeed, in much of Humphrey’s writing, it is not always clear to which species of primate he is referring (i.e., all primates, only some of them, or humans alone) For example, he suggests that young can learn “in some cases, from more formal lessons”, and that society functioned as a kind of “polytechnic school”, where youngsters would be freed from the demands of taking care of themselves, and so could “explore and experiment”.21 There are no formal lessons in either monkey and ape society and, once weaned, young animals must fend for themselves Thus, the picture painted by Humphrey often bears a much closer resemblance to human society than to that of any monkey or ape Indeed, it often seems to be simply a picture of human society projected back in time The implicit argument seems to be that, given that we have a good handle on our own cognitive capacities and the mechanisms that underpin them (a moot point), evolutionary continuity requires that these same abilities, or 21 Humphrey (1976: 310) © 2018 John Wiley & Sons Ltd 168 Philosophical Investigations their precursors, should be found in our closest living relatives Hence, the fact that the mechanisms were left unspecified may reflect the ease with which it could be assumed they would be similar to our own, and so the lack of precise detail went unnoticed (although not by everyone: Gigerenzer stated “[the social intelligence hypothesis] is vague because the nature of the intelligence it invokes is largely unclear, and as a consequence, the mechanisms of social intelligence have not yet been specified”).22 Of course, if one considers contemporary views of human psychology as flawed, and rejects the dominant computationalrepresentational picture of the mind, then, as I have argued elsewhere,23 we are simply compounding the error when we attempt to look for such mechanisms in other species Tracing the history of the social intelligence hypothesis thus reveals that the same “picture-based theorizing” that plagues human psychology operates here as well.24 This tendency to be held captive by a picture becomes even more apparent in studies extending the social brain hypothesis beyond the primates.25 Such studies have shown that the brain size–group size relationship is distinctively different in other taxa, particularly the birds and ungulates Here, pair-bonding (i.e., the formation of an enduring relationship between adult mates) emerges as the key correlate of enlarged brain size.26 Although one could argue this falsifies the original hypothesis, such a conclusion hinges on the use of group size as an appropriate measure of social complexity (which, as we have seen, is subject to flexible re-interpretation) To be fair, groups can often be large, anonymous aggregations (e.g., wildebeest migratory herds), so social complexity is not an automatic corollary of group size This being so, it serves simply to further highlight the flaws in using social group size as a measure of social complexity To wit, the complexity of social groups must derive from the complexity of the individuals that comprise such groups, so that they are more than just anonymous aggregations That is, individuals themselves render groups complex by possessing the ability to perceive such complexity Yet, it is the presence of a complex social group that is argued to have selected for this ability in the first place Again, Gigerenzer noted this circularity early on: “[t]he degree of perceived complexity, can hardly “explain” why there is a particular level of social 22 Gigerenzer (1997: 264) 23 Barrett (2011) 24 Hutto (2013) 25 Although other taxa not show the extremely large relative brain sizes of the primates, it follows that the same logic can be applied: social species should possess larger brains than non-social species, even if absolute brain size is small relative to the primates 26 Dunbar and Shultz (2007), Shultz and Dunbar (2007) © 2018 John Wiley & Sons Ltd Louise Barrett 169 intelligence in a species, because the perceived complexity is itself dependent on, or even part of, social intelligence”27 It is therefore interesting to note that it is precisely this circularity that has been used to reconfigure the social brain hypothesis Specifically, this reasoning has been used to provide a more precise delineation of the quantitative vs qualitative demands of sociality As already noted, the cognitive burden generated by the quantitative demands of tracking a large number of relationships was argued to rest on an underlying ability to perceive complexity in a qualitative fashion, that is, by conceptualizing different kinds of relationship, monitoring them though time, and using this information to manipulate others The discovery of an association between pair-bonding and relative brain size in birds and ungulates was therefore taken as evidence that it was this latter aspect, i.e., that of relationship quality, not quantity, that generated an evolutionarily important cognitive demand.28 To tie these new findings to the original quantitative effect among the primates, Dunbar and Shultz29 suggested that, in the primate order alone, the pair-bond relationship had been generalized to include all group members, so as to generate both a qualitative and a quantitative cognitive demand This reconfiguring of the original hypothesis obviously raises the question of what makes pair-bonding so cognitively demanding Dunbar30 argues for a variant of the original ‘relationship tracking’ hypothesis; namely, that individuals within a pair-bond must coordinate and synchronize their behaviour Being attentive to a mate’s needs, he argues: has many of the hallmarks that would be recognized as theory of mind in humans In effect, pair-bonded species have to be able to engage in perspective-taking, a phenomenon that is widely accepted as being a prerequisite for mentalizing (or theory of mind: Hare et al 2001, 2006) Hence, pair-bonded monogamy can perhaps be seen as laying the foundations for the kinds of advanced social cognition found (albeit in limited form) in primates and (perhaps uniquely in full-blown form) in humans.31 This seems to epitomize picture-based theorizing The notion that pairbonding must be cognitively demanding, and that such demand takes the form of perspective-taking, serves an explanatory need – it enables the social brain hypothesis to continue to cohere as a general theory of 27 Gigerenzer (1997: 266) 28 Dunbar and Shultz (2007), Shultz and Dunbar (2007), see also Dunbar & Shultz (2010) 29 Dunbar and Shultz (2007; also Dunbar (2009) 30 Dunbar (2009) 31 Dunbar (2009: 568) © 2018 John Wiley & Sons Ltd 170 Philosophical Investigations cognitive evolution – but is neither justified by the available evidence, nor supported by argument The reasoning continues to follow the logic identified in other iterations of the social intelligence/social brain hypothesis: assume (implicitly) the end-point to be human social intelligence, and project this onto other, closely related, species to arrive at the kinds of cognitive traits that ultimately will produce this outcome We not begin with “man as an animal”, in Witttgenstein’s words, but with a particular scientific construction of human mindedness, which we then extend far back into the evolutionary past In turn, this represents a prime example of ignoring Wittgenstein’s instruction to “don’t think Look!” There is no attention paid to the concrete situation of what pairbondedness requires of partners on a daily basis – no “horizontal attitude” in the words of van Dijk and Withagen.32 Instead, pair-bonded birds have to be able to engage in perspective-taking because this is what the theory requires, so that it can continue to arrive at its logical endpoint: our current scientific conception of human cognition Thus, in the context of the social brain hypothesis, “genuine” mindedness means being “Theory-of-Minded: to understand other living beings by means of an intellectual process that involves the formation of hypotheses and the drawing of inferences about the invisible mental states of others Although early work on monkeys33 suggested they lacked any ability to represent other’s psychological states, more recent work by Santos and colleagues claims that non-human primates can, in fact, attribute perceptions and knowledge to others, if not beliefs.34 V Logomorphism This need for mindedness to take a particular form also reflects the need for an evolutionary account of the origins of language, as this is another human end-point of the story Dunbar, for example, suggests: “[f]or humans, one important aspect of ToM concerns its relevance to language, a communication medium that crucially depends on understanding interlocutors’ mental states or intentions.”35 That is, a certain kind of mindedness must be in place prior to language, so that we can get to the forms of linguistic communication that are used to define our own species Language has to arise from a mentalizing mind (rather than certain 32 Van Dijk and Withagen (2014) 33 Cheney and Seyfarth (1992) 34 Flombaum and Santos (2005), Santos et al (2006), Marticorena et al (2011), Martin and Santos (2016) 35 Dunbar (1998: 189) © 2018 John Wiley & Sons Ltd Louise Barrett 173 “that much – not all, but much – of what we have always regarded as thinking is in fact acting or behaviour.”46 VI What we Study When we Study Mentalizing This is where Wittgenstein’s criticisms of psychology begin to bite Indeed, the ToM paradigm that drives much of the social intelligence/ brain hypothesis incorporates all of Wittgenstein’s criticisms into a single tidy package Most pertinently, the ToM paradigm places great emphasis on the idea that there is a “hidden” mind that sits behind our behaviour, and that understanding other living beings therefore requires inferences from “bare, bodily movements” to hidden psychological states The problems of this view as applied to human developmental and social psychology have been dealt with by other authors, including criticisms from a Wittgensteinian perspective.47 As mentioned above, Michael Bavidge and Ian Ground have also provided a clear and cogent criticism theory of mind as applied to other animals besides ourselves.48 I will not repeat these arguments here, other than to note that they not seem to have gained much purchase: studies of ToM continue apace, and ape researchers have recently claimed to have demonstrated that apes can attribute false beliefs to others (the Holy Grail of empirical work in this area).49 Why ToM retains such a grip on the psychological imagination is deserving of detailed sociological analysis, but all I want to here is briefly consider two ways that, since the publication of these earlier criticisms, the ToM paradigm continues to generate confusion and impossible problems for the study of animal minds First, let us, for the sake of argument, accept that the cognitivist model of mind is reasonable, and that scientific tests for “theory of mind” are worthwhile That is, let us assume that it is possible scientifically to test for this ability via competing hypotheses that can differentiate whether animals solve a given task via a cognitive mechanism that attributes mental states, or whether they use some alternative “nonmentalizing” learning mechanism The former kind of hypothesis has been termed a ‘booster’ hypothesis and the latter a ‘scoffer’50 – a revealing and interesting gloss in and of itself, as they anchor non-human animals to a human standard: either they will be ‘boosted’ to our level, or 46 Moyal-Sharrock (2016: 1-2) 47 Reddy (2008), Costall et al (2006) Leudar and Costall (2009), Sharrock and Coulter (2009), Sharrock (2009) 48 Bavidge and Ground (2011), see also Ground (2013) 49 Krupenye et al (2016) 50 Tomasello and Call (2006) © 2018 John Wiley & Sons Ltd 174 Philosophical Investigations their skills will be revealed as only apparent, a mockery of our own This issue aside, closer analysis of how such competing hypotheses are constructed and put to the test reveals that scientists who conduct tests in this way are not, in fact, doing what they claim to be doing – that is, testing for alternative cognitive mechanisms For example, Tomasello and Call consider the issue of whether chimpanzees “know what others see – or only what they are looking at” – i.e., they possess knowledge of seeing as a mental state.51 Among others, they discuss a series of experiments in which a subordinate chimpanzee is presented with the opportunity to retrieve a food reward to which a dominant chimpanzee either did or did not have visual access (because the food was placed behind an opaque barrier blocking the dominant’s view, but not the subordinate’s) Results supportive of the “booster” hypothesis, i.e., that the subordinate understood seeing (because they preferentially retrieved food that the dominant could not see) were contrasted with a number of scoffer hypotheses, e.g., the subordinate chimpanzees had learnt to forage in the vicinity of barriers because they accessed a higher proportion of food rewards when they did so The scoffer hypotheses were ruled out, and the mentalistic interpretation accepted, on the grounds that the former requires so many different learning mechanisms to explain all the different studies that it becomes implausible, and “[i]t is much more plausible to simply credit chimpanzees with understanding seeing”.52 The first thing to say here is that, if understanding were, in Wittgensteinian spirit, construed as an ability, this would not be a problem; the chimpanzees’ behaviour would be an expression of their ability to engage with more dominant individuals, and this would indeed provide evidence for their mindedness This is not what the authors are claiming, however They are arguing for a cognitive mechanism that enables chimpanzees to know “ something about the actual content of what the dominant could see and had seen in the immediate past”.53 But, unlike in (some of) the scoffer cases, no mechanism has been specified As Penn has argued, instead of embracing the idea that cognitive processes are computational, rule-governed, algorithmic processes, comparative psychologists actually aim to dismiss this possibility in favour of demonstrating that animals have an “understanding of” or “insight into” a particular folk psychological concept The word “cognitive”, Penn argues, has thus become synonymous with “mentalistic”, “conscious” or “insightful” or, as Tomasello and Call put it, with the notion that “apes 51 Tomasello and Call (2006) 52 Tomasello and Call (2006: 382) 53 Tomasello and Call (2006: 376), emphasis in the original © 2018 John Wiley & Sons Ltd Louise Barrett 175 54 really know what others and not see” (emphasis added) As Penn further notes, this is actually a strongly anti-cognitivist position: the mentalistic mechanisms are presented as alternatives to computational or algorithmic processes, when they are really just short-hand folk psychological descriptions of such processes As such, they have abandoned the fundamental tenets of the cognitive revolution, which they otherwise defend so strongly.55 VII Povinelli’s Problem: Logical or Ludicrous? Related to this confusion is a second one, known as the “logical problem” or “Povinelli’s problem”.56 Daniel Povinelli is famous for initially being a strong advocate of the ToM paradigm in comparative psychology, and then flipping to an equally extreme alternative position, when his own detailed studies of chimpanzees failed to demonstrate that chimpanzees had any kind of insight into others’ mental states His argument shifted in favour of ToM being a human-specific adaptation Povinelli further suggested that, as any human mentalizing abilities were built on top of and integrated into, an ape-level ability to represent and read behaviour, it would be impossible to know, on the basis of non-verbal experimental evidence, whether a human being (let alone a chimpanzee) was using a behaviour-reading mechanism or a mentalizing mechanism to solve a task: both mechanisms predict the use of observable behavioural cues and, as such, they cannot be distinguished from each other.57 Thus, Povinelli’s problem can be specified as follows: given that inferences about hidden mental states are made on the basis of bodily and environmental cues, it follows that, for any mentalistic hypothesis, there is a complementary “behaviour-reading” hypothesis that can explain the data equally well.58 The idea here, then, is that the cognitive mechanisms that underpin mind-reading (whatever these may be) operate over representations of bodily/environmental cues and mental states, whereas the mechanisms involved in complementary behaviour-reading (whatever these may be) operate over representations of bodily and environmental cues alone Povinelli’s problem is thus another manifestation of the confusion inherent in the theory of mind paradigm – namely, that behaviour is bare, 54 55 56 57 58 Tomasello and Call (2006: 371) Penn (2011) Lurz (2009, 2011), Lurz and Krachun (2011), Lurz et al (2014) Povinelli et al (2000), Povinelli and Vonk (2004) Lurz (2009) © 2018 John Wiley & Sons Ltd 176 Philosophical Investigations bodily movement, that can only ever function as a cue to mindedness, rather than being seen as its expression What is notable about Povinelli’s position, however, is that he considers chimpanzees to be fully representational beings (i.e., he is a committed cognitivist, and not a behavourist of any stripe) That is, some form of contentful mind continues to sit behind behaviour, and it is this which imbues behaviour with meaning Those who accept Povinelli’s problem therefore accept a picture of the mind that, as Bavidge and Ground previously identified, requires moves that actually make it impossible to raise questions about animal minds That is, for Povinelli’s problem to have any purchase, one has to accept that (1) “genuine knowledge of other minds is identified with a form of ‘scientific knowledge’” (i.e., all the hypotheses and inferences and the like); (2) “that ‘behaviour’ is emptied of any psychological content”, and (3) that “what counts as “observable” is restricted to what a mind-blind computer information processor would record”.59 Consequently, the debate “amounts to asking whether or not non-human animals have interiorized one or other of the false pictures of intentional agency that have so bedevilled our account of the human mind”.60 In other words, if our only option is to ask whether animals are Cartesians or Behaviourists, how can we expect to come up with any kind of meaningful answer? For the comparative psychologist held captive by this picture these are, of course, precisely the options on offer Consequently, Povinelli’s problem is seen as presenting a solely empirical challenge: to design an experiment that can pull apart a complementary behaviour-reading account from a mentalizing account – one that can demonstrate that a target animal is reasoning about mental states, while simultaneously ruling out the possibility that the observable behaviours alone could explain the target animal’s response Efforts to have achieve this have involved designs where some form of behaviour (often that of a human experimenter) is held constant during a critical phase of the experiment Under such conditions, it is argued, the chimpanzee would have to reason about the human’s beliefs, goals or intentions to succeed For example, Buttelman and colleagues investigated whether chimpanzees could use context to infer a potential change in a human experimenter’s goals.61 The chimpanzees were tested in two familiar adjoining enclosures A bucket containing grapes, plus a stool for the experimenter to sit on (a “feeding station”) was set up in front of each enclosure and, in warm-up sessions, the chimpanzees 59 Bavidge and Ground (2011) 60 Bavidge and Ground (2011) 61 Buttelmann et al (2012) © 2018 John Wiley & Sons Ltd Louise Barrett 177 learned that a human experimenter would feed them a certain, unpredictable number of grapes from one feeding station (A), stand up, walk over to the other station (B), and feed the chimpanzee more grapes from this location Thus, as the experimenter rose from her seat, and moved to station B, the chimpanzee could anticipate her movements, and travel from one testing room through to the other, and could so receive food from the experimenter at station B In testing sessions, a barrier was introduced between the two feeding stations to slow down the experimenter and so give the chimpanzee more time to make a prediction about where she might head in each trial During these sessions, the chimpanzees experienced the same feeding trials as before, but now the experimenter needed to step over the barrier as she made her way to station B When doing so, the experimenter looked only at the barrier or the wall behind it, pausing briefly (by an inconspicuous line marked on the floor, the “criterion line”), and then proceeding to the station B During testing sessions, the chimpanzees also experienced experimental trials where some external event made the experimenter stop feeding at location A In one condition, a walkie-talkie placed on the floor near Station B would receive an incoming call In a second condition, the experimenter would stop, look towards station B, call to another experimenter outside the room and ask for a clipboard The second experimenter would then throw this into the room, via a door behind station B, where it would land as a spot between A and B In a third condition, the second experimenter would call the first experimenter by name, and beckon her to come outside Whatever external event occurred, the experimenter would respond identically as follows: she would turn her head towards location B, look towards the stool at this location, look back to the chimpanzee, get up, turn towards the barrier, step over it as before, and pause by the line on the floor From this point on, her behaviour varied depending on condition (i.e., she would pick up the walkie-talkie and speak into it; she would pick up the clipboard; she would leave the room) The authors of the study reasoned that, as the experimenter’s behaviour was identical between the occurrence of the external event to the point where she reached the criterion line, a chimpanzee that could only read behaviour would not recognize that the experimenter’s goal (of feeding grapes from station B) had changed, and so would proceed to station B as usual In contrast, a chimpanzee capable of realizing that the experimenter’s internal goal had changed as a result of the external event, would hesitate, inferring that the experimenter was likely to attend to the source of the disturbance The results showed that chimpanzees hesitated around seconds longer on average in the experimental trial than during baseline “warm-up” feeding or during a control trial (where the experimenter placed a © 2018 John Wiley & Sons Ltd 178 Philosophical Investigations clipboard on her lap, while feeding the chimpanzee at station A, then picked it up and deliberately dropped it at her side before standing and proceeding to station B) The authors therefore concluded that the chimpanzees were making their decision on the basis of understanding the experimenter’s goals, and not simply responding to concurrent cues I have explained the design in some detail as I find it striking how closely it adheres to the tactical moves identified by Bavidge and Ground, particularly their third point about ‘mind-blind computers’.62 We are asked to accept that a non-mentalizing animal would somehow fail to register any other difference between warm-up and experimental conditions besides the contingency between the experimenter, the buckets and her movements Moreover, the authors of the study also argued that, as the chimpanzee’s behaviour differed between the control and the ‘clipboard’ condition, the contextual feature of “clipboard on the ground” could not have been used as the sole discriminative stimulus If it had, the chimpanzees behaviour would then have been the same in the two conditions That is, the authors are arguing that a chimpanzee would not register any difference between a person throwing a clipboard down beside them, and another person throwing it into the room from outside Similarly, the argument that the animals could have previously learned context cues (i.e., were familiar with people using walkie-talkies, requesting items from each other, leaving a room in response to another’ call) was ruled on the basis that all the events they had witnessed in the testing room were entirely novel; as the chimpanzees could not have learned any of those specific associations previously, their behaviour therefore required a richer, mentalistic interpretation Thus, it is not the mentalizing hypothesis and its interpretation that is outlandish here, but the behaviour-reading one – for it treats a non-theory-of-minded animal as some kind of inanimate, robotic mechanism No one (including modern radical behaviourists), would assume that the inability to infer and attribute mental states entails seeing the world only in terms of the colourless movements of limbs and other body parts Nor would a radical, molar behaviourist assume that animals register only the most shallow, surface features of the world (“clipboard on the floor”), rather than a richly detailed sequences of events and interactions, in which their own actions play a role To lack a scientific theory of mind is not to lack any kind of mind or mentality at all Instead, as Hacker puts it “ .behaviour is grasped as animate – as the behaviour of a living animal It is perceived as a manifestation or expression of cognitive, cogitative, affective and volitional powers, and is so described.”63 Yet, to 62 Bavidge and Ground (2011) 63 Hacker (2013: 89) © 2018 John Wiley & Sons Ltd Louise Barrett 179 satisfy the strictures of Povinelli’s problem, researchers are forced into adopting this all or nothing view64 – this clearly seems to be a case where, as Tejedor argues, scientism is as bad for scientists as it is for everyone else.65 It is also worth pondering whether this caricatured view of behaviour potentially explains why mentalizing interpretations seem to provide an explanation of mechanism Steven Pinker (2003), for example, in making a case against behaviourism and in favour of the computational theory of mind, writes: “How might we explain why Rex just walked over to the phone? We would not say that phone-shaped stimuli caused Rex’s limbs to move in certain arcs”.66 Indeed not, but again, nor would any selfrespecting radical behaviourist (of course, it’s always easier to shoot straw men in a barrel, as my husband would say) Instead, Pinker offers that: “we might say that he wanted to speak to his friend Cecile and knew that Cecile was home No explanation has as much predictive power as that one.”67 But this provides no explanation at all in terms of the internal, computational mechanisms that produced Rex’s behaviour, which is what the computational theory of mind claims to provide It only seems to be a deeper kind of explanation because the alternative is so obviously fatuous, and it allows the mindedness we see manifest in behaviour to be absorbed into the computational theory That is, because mentalistic theory of mind explanations are couched in terms of our ordinary folk psychological language, and because this captures the expression of a person’s joy, anger, puzzlement or pain in their behaviour, we take this as evidence for the inferential and inductive processes that the current scientific picture argues to be responsible for these abilities Similarly, when other animals respond to, and interact appropriately with each other in ToM experiments, this is taken to be evidence for the mentalistic inferential processes, because the only other option available is to see “limbs moving in certain arcs.” 64 What is worse, perhaps, is that the design of such experiments may not satisfy many critics of the mentalizing hypothesis: the argument for the extreme novelty of the experimental scenarios excluding previous learning is rather weak, for example, plus the small difference in the chimpanzees’ performance (a 2-second difference between conditions), in scenarios that seem clear-cut from our perspective, would suggest they were not responding solely to the change in the experimenter’s goal (of course, given how bizarrely, and robotically, the experimenter behaves in the middle portion of each test – surely the only truly novel part of the whole experiment – it is remarkable the chimpanzees responded as strongly as they did) 65 Tejedor (2017) 66 Pinker (2003: 32) 67 Pinker (2003: 32) © 2018 John Wiley & Sons Ltd 180 Philosophical Investigations Some researchers, most notably Lurz and colleagues, have suggested that a new empirical approach is needed to solve Povinelli’s problem68 : one that involves manipulating appearances and reality in ways that only a mentalizing animal would be capable of understanding (e.g., tests using distorting lenses, that would require an animal to understand that how an object appears to them is distinctively different from how it appears to another).69 Lurz and his co-workers thus remain “optimistically agnostic” about the mentalizing abilities of apes, and that having solved Povinelli’s problem, we will soon acquire the necessary scientific evidence that apes attribute mental states.70 Indeed, recent evidence suggests that chimpanzees have shown some positive evidence that they can pass these more stringent tests But these tests require chimpanzees to behave even more like human behavioural scientists, with the behaviour-reading alternative becoming ever more colourless and empty My view is that Povinelli’s problem cannot be solved empirically because it is an impossible problem, it can only be dissolved by conceptual investigation It is a symptom of a view of mind that “ .is the sublimate of closet-Cartesian philosophy of mind in the form of a scientific methodology”.71 What we need is to appreciate Wittgenstein’s insight that expressive behaviours are criteria for appropriate psychological attributions, not inductive evidence for them Once we so, the notion that we can pull behaviour and mind apart via clever experimentation is revealed as nonsensical, as is the notion that genuine knowledge of others requires possession of a specific theory about other’s invisible mental states VIII Enaction and Ethology It is time, therefore, to get free of this picture of the theory-of-minded mind, and embrace a better kind of continuity between ourselves and other species We need to reject the idea that cognition ‘always and everywhere involves content’ (Hutto and Myin 2012), and see things as Wittgenstein does, as “cognition as always and everywhere involving man as an animal”, where “at the beginning is the deed’, not the word, 68 Lurz (2009, 2011), Lurz and Krachun (2011), Lurz et al (2014) 69 Krachun et al (2009); Krachun et al (2016) 70 Lurz et al (2014) Although, even here, I suspect these experiments will not remain criticism-free, especially if apes fail them, as the design seems vulnerable to participants suffering from the so-called ‘curse of knowledge’ (i.e., the tendency to be biased by one’s own knowledge when asked to judge from a naive perspective) This is known to disrupt the performance of adult humans and children in tests requiring the understanding of perspective and the attribution of mental states (see Birch and Bloom 2004) 71 Bavidge and Ground (2009: 182) © 2018 John Wiley & Sons Ltd Louise Barrett 181 72 not the proposition, but the deed, action” , such that our most fundamental beliefs, our “hinge certainties” are practical in nature, “ .a kind of animal, unreasoned, unhesitating belief A belief that cannot meaningfully be said, but only shown, in our actions”73 In other words, we need radical embodied cognitive science and enactivism.74 This is the difference between taking the position that “The dog thinks there is a rabbit” means “there is a piece of mental content in the dog’s head which represents there being a rabbit and the dog stands in the attitude of belief towards this content” and one that takes Wittgenstein’s advice, and says “Look instead at what the dog does And there you will see the thinking.”75 Our focus should be on expressive behaviour, where the scientific approach used is that of ethology, and where our job “ .is to discover how the species-specific behaviour – and not the behaviourist ‘behaviour’ – of animals is significant for themselves and their conspecifics in the contexts in which they live.”76 Even better, Ground77 suggests, would be to talk of “expressive enactions”, rather than behaviours For this would maintain the “central deed-like performative aspect of expression, the relevant constitutive aspect and the essential connection to embodiment” and would tie Wittgenstein’s emphasis on the centrality of expression to new work in radical enactivism (as expression is content-free).78 Taking this path, we can substitute the scientistic view that primate knowledge should be modelled on that possessed by human cognitive and behaviourist scientists, for a view in which “the primate has something like the kind of knowledge of its conspecifics that you and I may have of each other and which is about the sort of entities that make up social relationships: namely the actions, reactions and interactions of psychological beings”79 It is time, in other words, to wield “Wittgenstein’s razor” As MoyalSharrock has written, “there is hardly anything traditionally thought to be emergent from, underwritten by, or reducible to a mental process or state, that Wittgenstein has not subjected to the razor of enactivism; that is: is shown to be primitively embodied or enacted rather than originating in propositions, theories of mind, or ghostly processes”.80 We need to pare away the superfluous intellectualism that obscures our view of primate forms of life, for it prevents us from recognizing the deep 72 73 74 75 76 77 78 79 80 Moyal-Sharrock (2007: 98) Moyal-Sharrock (2007: 98) Chemero (2009); Hutto and Myin (2012, 2017) Ground (2013: 18) Bavidge and Ground (2011: 182) Ground (2013: 18) Hutto and Myin (2012, 2017) Bavidge and Ground (2011: 180) Moyal-Sharrock (2013: 266) © 2018 John Wiley & Sons Ltd 182 Philosophical Investigations evolutionary continuity between ourselves and our primate cousins, as active, living organisms engaged in the ‘hurly-burly’ of life Department of Psychology University of Lethbridge Alberta T1K 3M4 Canada louise.barrett@uleth.ca References Barrett, L (2010) “Too much monkey business.” In G Semin and G Echterhof (eds.), Grounding Sociality, Brighton, UK: Psychology Press, pp 207–224 ——— (2011) Beyond the Brain: How Body and Environment Shape Animal and Human Minds, Princeton, NJ: Princeton University Press ——— (2012) “Why Behaviourism isn’t Satanism.” In J Vonk and T Shackelford (eds.), The Oxford Handbook of Comparative Evolutionary Psychology, New York, NY: Oxford University Press, pp 17–38 ——— (2015a) “Back to the rough ground and into the hurly-burly: why cognitive ethology needs Wittgenstein’s razor.” In D MoyalSharrock, V Munz and A Coliva (eds.), Mind, Language and Action: Proceedings of the 36th International Wittgenstein Symposium, Berlin, Germany: De Gruyter, pp 299–316 ——— (2015b) “A Better Kind of Continuity.” The Southern Journal of Philosophy 53(s1): 28–49 ——— (2016) “Why Brains are not Computers, why Behaviourism isn’ Satanism, and why Dolphins are not Aquatic Apes.” Behavior Analyst 39: 9–23 ——— and S P Henzi (2005) “The Social Nature of Primate Cognition.” Proceedings of the Royal Society, London, Series B 272: 1865–1875 ——— R I M Dunbar and J E Lycett (2001) Human Evolutionary Psychology, Princeton, NJ: Princeton University Press ——— S P Henzi and R I M Dunbar (2003) “Primate Cognition: from ‘what now?’ to ‘what if?” Trends in Cognitive Sciences 7: 494– 497 ——— and D Rendall (2007) “Social Brains, Simple Minds: Does Behavioural Complexity Really Require Cognitive Complexity?” Philosophical Transactions of the Royal Society of London Series B, Biological Sciences 362: 561–575 © 2018 John Wiley & Sons Ltd Louise Barrett 183 ——— and D Lusseau (2012) “Taking Sociality Seriously: the Structure of Multi-Dimensional Networks as A Source of Information for Individuals.” Philosophical Transactions of the Royal Society of London Series B, Biological Sciences 367: 2108–2118 Barton, R A (1998) “Visual Specialization and Brain Evolution in Primates.” Proceedings of the Royal Society, London, Series B 265: 1933– 1937 ——— (2004) “Binocularity and Brain Evolution in Primates.” Proceedings of the National Academy of Sciences of the United States of America 101: 10113–10115 ——— and C Venditti (2014) “Rapid Evolution of the Cerebellum in Humans and other Great Apes.” Current Biology 24(20): 2440–2444 ——— A Purvis and P H Harvey (1995) “Evolutionary Radiation of Visual and Olfactory Brain Systems in Primates, Bats and Insectivores.” Philosophical Transactions of the Royal Society of London Series B, Biological sciences 348: 381–392 Bavidge, M and I Ground (2011) “Do animals needs a ‘theory of mind’.” In I Leudar and A Costall (eds.), Against Theory of Mind, Basingstoke, London: Palgrave-Macmillan, pp 167–190 Birch, S A and P Bloom (2004) “Understanding Children’s and Adults’ Limitations in Mental State Reasoning.” Trends in Cognitive Sciences 8: 255–260 Buttelmann, D., S Sch€ utte, M Carpenter, J Call and M Tomasello (2012) “Great Apes Infer others’ Goals Based on Context.” Animal Cognition 15: 1037–1053 Byrne, R W (1997) “Machiavellian Intelligence.” Evolutionary Anthropology 5: 172–180 ——— and N Corp (2004) “Neocortex Size Predicts Deception Rate in Primates.” Proceedings of the Royal Society B: Biological Sciences 271 (1549): 1693–1699 Byrne, R and A Whiten (1989) Machiavellian Intelligence: Social Expertise and the Evolution of Intellect in Monkeys, Apes, and Humans, Oxford, UK: Blackwells Chemero, A (2009) Radical Embodied Cognitive Science, Cambridge, MA: The MIT press Cheney, D L and R M Seyfarth (1992) How Monkeys see the World: Inside the Mind of Another Species ——— (2005) “Constraints and Preadaptations in the Earliest Stages of Language Evolution.” The Linguistic Review 22: 135–159 Costall, A., I Leudar and V Reddy (2006) “Failing to See the Irony in ‘Mind-Reading’.” Theory & Psychology 16: 163–167 © 2018 John Wiley & Sons Ltd 184 Philosophical Investigations DeCasien, A R., S A Williams and J P Higham (2017) “Primate Brain Size is Predicted by Diet but not Sociality.” Nature Ecology & Evolution 1: 112 Dunbar, R I M (1992) “Neocortex Size as a Constraint on Group Size in Primates.” Journal of Human Evolution 22: 469–493 ——— (1995) “Neocortex Size and Group Size in Primates: A Test of the Hypothesis.” Journal of Human Evolution 28: 287–296 ——— (1998) “The Social Brain Hypothesis.” Evolutionary Anthropology 6: 178–190 ——— (2003) The social brain: mind, language, and society in evolutionary perspective Annual Review of Anthropology, pp.163–181 ——— (2009) “The Social Brain Hypothesis and its Implications for Social Evolution.” Annals of Human Biology 36: 562–572 Dunbar, R I M and S Shultz (2007) “Bondedness and sociality.” Behaviour 147: 775–803 Dunbar, R I and S Shultz (2007) “Evolution in the Social Brain.” Science 317(5843): 1344–1347 ——— (2010) Bondedness and sociality Behaviour, 147: 775–803 Dunbar, R I M and S Shultz (2017) “Why are there so many Explanations for Primate Brain Evolution?” Philosophical Transactions of the Royal Society of London Series B, Biological Sciences 372: 20160244 Flombaum, J I and L R Santos (2005) “Rhesus Monkeys Attribute Perceptions to Others.” Current Biology 15: 447–452 Gigerenzer, G (1997) “10 The Modularity of Social Intelligence.” Machiavellian Intelligence II: Extensions and Evaluations 2: 264 264-288 Ground, I (2013) Listen to the Lion Tenth British Wittgenstein Society Lecture Hacker, P M S (2013) Wittgenstein: Comparisons and Context, Oxford, UK: OUP Hare, B., Call, J., and Tomasello, M (2001) “Do chimpanzees know what conspecifics know?.” Animal behaviour 61: 139–151 Hare, B., Call, J., and Tomasello, M (2006) “Chimpanzees deceive a human competitor by hiding.” Cognition 101: 495–514 Humphrey, N K (1976) “The social function of intellect.” In P P G Bateson and R A Hinde (ed.), Growing Points in Ethology, Cambridge, UK: Cambridge University Press, pp 303–317 Hutto, D (2013) “Enactivism, from a Wittgensteinian Point of View.” American Philosophical Quarterly 50(3): 281–302 Hutto, D D and E Myin (2012) Radicalising Enactivism: Basic Minds Without Content, Cambridge, MA: The MIT Press ——— (2017) Evolving Enactivism: Basic Minds Meet Content, Cambridge, MA: MIT Press © 2018 John Wiley & Sons Ltd Louise Barrett 185 Jolly, A (1966) “Lemur Social Behavior and Primate Intelligence.” Science 153(3735): 501–506 Krachun, C., J Call and M Tomasello (2009) “Can Chimpanzees (Pan troglodytes) Discriminate Appearance from Reality?” Cognition 112: 435–450 ——— R Lurz, J L Russell and W D Hopkins (2016) “Smoke and Mirrors: Testing the Scope of Chimpanzees’ Appearance–Reality Understanding.” Cognition 150: 53–67 Krupenye, C., F Kano, S Hirata, J Call and M Tomasello (2016) “Great Apes Anticipate that other Individuals will Act According to False Beliefs.” Science 354: 110–114 Kudo, H and R Dunbar (2001) “Neocortex Size and Social Network size in Primates.” Animal Behaviour 62: 711–722 Leudar, I and A Costall (2009) Against Theory of Mind, Basingstoke, London: Palgrave-Macmillan Lurz, R (2009) “If Chimpanzees are Mindreaders, could Behavioral Science Tell? Toward a Solution of the Logical Problem.” Philosophical Psychology 22: 305–328 Lurz, R W (2011) “Belief Attribution in Animals: On how to Move Forward Conceptually and Empirically.” Review of Philosophy and Psychology 2: 19–59 ——— and C Krachun (2011) “How could we know Whether Nonhuman Primates Understand others’ Internal Goals and Intentions? Solving Povinelli’s Problem.” Review of Philosophy and Psychology 2: 449 ——— S Kanet and C Krachun (2014) “Animal Mindreading: A Defense of Optimistic Agnosticism.” Mind & Language 29: 428–454 Marticorena, D C., A M Ruiz, C Mukerji, A Goddu and L R Santos (2011) “Monkeys Represent others’ Knowledge but not their Beliefs.” Developmental Science 14: 1406–1416 Martin, A and L R Santos (2016) “What Cognitive Representations Support Primate Theory of Mind?” Trends in Cognitive Sciences 20: 375–382 Moyal-Sharrock, D (2007) Understanding Wittgenstein’s On Certainty, Basingstoke, London: Palgrave Macmillan ——— (2013) “Wittgenstein’s Razor: The Cutting Edge of Enactivism.” American Philosophical Quarterly 50(3): 263–279 ——— (2016) Wittgenstein Today Wittgenstein-Studien 7: 1–15 Pawlowski, B., C B Lowen and R I M Dunbar (1998) “Neocortex Size, Social Skills and Mating Success in Primates.” Behaviour 135: 357–368 Penn, D (2011) “How folk psychology ruined comparative psychology: And how scrub jays can save it.” In R Menzel and J Fischer (ed.), © 2018 John Wiley & Sons Ltd 186 Philosophical Investigations Animal thinking: Contemporary Issues in Comparative Cognition, Cambridge, MA: MIT Press, pp 253–266 Pinker, S (2003) The blank slate: The modern denial of human nature Penguin, London Povinelli, D J and J Vonk (2004) “We don’t Need a Microscope to Explore the Chimpanzee’s Mind.” Mind & Language 19: 1–28 ——— J M Bering and S Giambrone (2000) “Toward a Science of other Minds: Escaping the Argument by Analogy.” Cognitive Science 24: 509–541 Powell, L E., K Isler and R A Barton (2017) “Re-Evaluating the Link between Brain Size and Behavioural Ecology in Primates.” Proceedings of the Royal Society of London Series B 284: 20171765 Premack, D (1989) “Does the Chimpanzee Have a Theory of Mind” Revisited.” In R W Byrne and A Whiten (eds.), Machiavellian Intelligence: Social Expertise and the Evolution of Intellect in Monkeys, Apes, and Humans, Oxford, UK: Blackwells ——— and G Woodruff (1978) “Does the Chimpanzee have a Theory of Mind?” Behavioral and Brain Sciences 1: 515–526 Reddy, V (2008) How Infants Know Minds, Cambridge, MA: Harvard University Press Santos, L R., A G Nissen and J A Ferrugia (2006) “Rhesus Monkeys, Macaca Mulatta, know what others can and cannot Hear.” Animal Behaviour 71: 1175–1181 Segerdahl, P (2012) Humanising non-humans: Ape language research as critique of metaphysics In: N Forsberg, M Burley and N H€am€al€ainen (ed.), Language, Ethics and Animal Life: Wittgenstein and Beyond, London, UK: Bloomsbury Academic, pp 16–31 Seyfarth, R M and D L Cheney (2014) “The Evolution of Language from Social Cognition.” Current Opinion in Neurobiology 28: 5–9 ——— and P Marler (1980) “Vervet Monkey Alarm Calls: Semantic Communication in a Free-Ranging Primate.” Animal Behaviour 28: 1070–1094 Sharrock, W (2009) “Closet Cartesianism in discursive psychology.” In I Leudar and A Costall (eds.), Against Theory of Mind, Basingstoke, London: Palgrave-Macmillan, pp 191–208 ——— and J Coulter (2009) “‘Theory of Mind’: A critical commentary continued.” In I Leudar and A Costall (eds.), Against Theory of Mind, Basingstoke, London: Palgrave-Macmillan, pp 56–90 Shultz, S and R I Dunbar (2007) “The Evolution of the Social Brain: Anthropoid Primates Contrast with other Vertebrates.” Proceedings of the Royal Society of London Series B 274: 2429–2436 © 2018 John Wiley & Sons Ltd Louise Barrett 187 Tejedor, C (2017) “Scientism as a Threat to Science: Wittgenstein on Self-Subversive Methodologies.” In J Beale and I J Kidd (eds.), Wittgenstein and Scientism, Abingdon, London: Routledge, pp 7–27 Tomasello, M and J Call (2006) “Do chimpanzees know what others see–or only what they are looking at?” In S Hurly and M Nudds (eds.), Rational Animals?, Oxford, UK: Oxford University Press, pp 371–384 Van Dijk, L and R Withagen (2014) “The Horizontal Worldview: A Wittgensteinian Attitude towards Scientific Psychology.” Theory & Psychology 24: 3–18 Wittgenstein, L (1953) Philosophical Investigations, Oxford, UK: Blackwell © 2018 John Wiley & Sons Ltd ... pair-bonding and relative brain size in birds and ungulates was therefore taken as evidence that it was this latter aspect, i.e., that of relationship quality, not quantity, that generated an evolutionarily... there being a rabbit and the dog stands in the attitude of belief towards this content” and one that takes Wittgenstein? ??s advice, and says “Look instead at what the dog does And there you will... Philosophical Investigations clipboard on her lap, while feeding the chimpanzee at station A, then picked it up and deliberately dropped it at her side before standing and proceeding to station B) The