An individual has a theory of mind if he imputes mental states to himself and others. A system of inferences of this kind is properly viewed as a theory because such states are not directly observable, and the system can be used to make predictions about the behavior of others. As to the mental states the chimpanzee may infer, consider those inferred by our own species, for example, purpose or intention, as well as knowledge, belief, thinking, doubt, guessing, pretending, (...) liking, and so forth. To determine whether or not the chimpanzee infers states of this kind, we showed an adult chimpanzee a series of videotaped scenes of a human actor struggling with a variety of problems. Some problems were simple, involving inaccessible food as in the original Kohler problems; others were more complex, involving an actor unable to extricate himself from a locked cage, shivering because of a malfunctioning heater, or unable to play a phonograph because it was unplugged. With each videotape the chimpanzee was given several photographs, one a solution to the problem, such as a stick for the inaccessible bananas, a key for the locked up actor, a lit wick for the malfunctioning heater. The chimpanzee's consistent choice of the correct photographs can be understood by assuming that the animal recognized the videotape as representing a problem, understood the actor's purpose, and chose alternatives compatible with that purpose. (shrink)
The question of whether chimpanzees, like humans, reason about unobservable mental states remains highly controversial. On one account, chimpanzees are seen as possessing a psychological system for social cognition that represents and reasons about behaviors alone. A competing account allows that the chimpanzee's social cognition system additionally construes the behaviors it represents in terms of mental states. Because the range of behaviors that each of the two systems can generate is not currently known, and because the latter system depends (...) upon the former, determining the presence of this latter system in chimpanzees is a far more difficult task than has been assumed. We call for recognition of this problem, and a shift from experimental paradigms that cannot resolve this question, to ones that might allow researchers to intelligently determine when it is necessary to postulate the presence of a system which reasons about both behavior and mental states. (shrink)
I respond to an argument presented by Daniel Povinelli and Jennifer Vonk that the current generation of experiments on chimpanzee theory of mind cannot decide whether chimpanzees have the ability to reason about mental states. I argue that Povinelli and Vonk’s proposed experiment is subject to their own criticisms and that there should be a more radical shift away from experiments that ask subjects to predict behavior. Further, I argue that Povinelli and Vonk’s theoretical commitments should lead them to (...) accept this new approach, and that experiments which offer subjects the opportunity to look for explanations for anomalous behavior should be explored. (shrink)
on ). -/- Advice about how to move forward on the mindreading debate, particularly when it comes to overcoming the logical problem, is much needed in comparative psychology. In chapter 4 of his book Ockham’s Razors, Elliott Sober takes on the task by suggesting how we might uncover the mechanism that mediates between the environmental stimuli that is visible to all, and chimpanzee social behavior. I argue that Sober's proposed method for deciding between the behaivor-reading and mindreading hypotheses fails (...) given the nature of each of those hypotheses. I argue that the behavior-reading hypothesis that Povinelli and colleagues propose is so rich and robust that it is going to make predictions that are behaviorally indiscernible from the mindreading hypothesis. Further, I argue that the logical problem artificially separates one’s knowledge of behavior and one’s knowledge of mind. If we reject this form of dualism, the logical problem doesn’t arise. (shrink)
Since the question “Do chimpanzees have a theory of mind?” was raised in 1978, scientists have attempted to answer it, and philosophers have attempted to clarify what the question means and whether it has been, or could be, answered. Mindreading or theory of mind refers to the ability to attribute mental states to other individuals. Some versions of the question focus on whether chimpanzees engage in belief reasoning or can think about false belief, and chimpanzees have been given nonverbal versions (...) of the false belief moved-object task. Other versions of the question focus on whether chimpanzees understand what others can see, and chimpanzees can pass those tests. From this data, some claim that chimpanzees know something about perceptions, but nothing about belief. Others claim that chimpanzees do not understand belief or perceptions, because the data fails to overcome the “logical problem,” and permits an alternative, non-mentalistic interpretation. I will argue that neither view is warranted. Belief reasoning in chimpanzees has focused on examining false belief in a moved object scenario, but has largely ignored other functions of belief. The first part of the paper is an argument for how to best understand belief reasoning and offers suggestion for future investigation. The second part of the paper addresses and diffuses the “logical problem.” I conclude that chimpanzees may reason about belief, but that there is already compelling evidence that they reason about perceptions. (shrink)
This paper develops the hypothesis that languages may be learned by means of a kind of cause-effect analysis. This hypothesis is developed through an examination of E. Sue Savage-Rumbaugh's research on the abilities of chimpanzees to learn to use symbols. Savage-Rumbaugh herself tends to conceive of her work as aiming to demonstrate that chimpanzees are able to learn the "referential function" of symbols. Thus the paper begins with a critique of this way of viewing the chimpanzee's achievements. The hypothesis (...) that Savage-Rumbaugh's chimpanzees learn to use symbols by means of cause-effect analysis is then supported through a detailed examination of the tasks they have learned to perform. Next, it is explained how language-learning in humans might be conceptualized along similar lines. The final section attempts to explain how the pertinent cause-effect analysis ought to be conceived. (This paper was published with a reply by Savage-Rumbaugh. See the same issue, pp. 55-76.). (shrink)
I analyze two recent parsimony arguments that have been offered to break the current impasse in the chimpanzee mindreading controversy, the ‘logical problem’ argument from Povinelli, Penn, and Vonk, and Sober's attempt to apply model selection criteria in support of the mindreading hypothesis. I argue that Sober's approach fails to adequately rebut the ‘logical problem’. However, applying model selection criteria to chimpanzees' own mental models of behavior does yield a response to the ‘logical problem’ and reveals an adaptive advantage (...) of mindreading models and a potential solution to a paradox raised by Whiten. (shrink)
This chapter compares the social behaviour of human hunter-gatherers with that of the better-studied chimpanzee species, Pan troglodytes, in an attempt to pinpoint the unique features of human social evolution. Although hunter-gatherers and chimpanzees living in central Africa have similar body weights, humans live at much lower population densities due to their greater dependence on predation. Human foraging parties have longer duration than those of chimpanzees, lasting hours rather than minutes, and a higher level of mutual dependence, through the (...) division of labour between men and women ; which is in turn related to pair-bonding, and meat sharing to reduce the risk of individual hunters' failure on any particular day. The band appears to be a uniquely human social unit that resolves the tension between greater dispersion and greater interdependence. (shrink)
Among the "hard cases" of captive animal research is the continued use of chimpanzees in harmful experimental science. In a recent article I contend that contemporary animal welfare science and chimpanzee behavioral studies permit, if not require, a reappraisal of the moral significance of chimpanzee dissent from participation in certain experiments. In what follows, I outline my earlier argument, provide a brief survey of some central concepts in pediatric research ethics, and use these to enrich an understanding of (...)chimpanzee dissent useful for research ethics. (shrink)
The advanced sensory, psychological and social abilities of chimpanzees confer upon them a profound ability to suffer when born into unnatural captive environments, or captured from the wild – as many older research chimpanzees once were – and when subsequently subjected to confinement, social disruption, and involuntary participation in potentially harmful biomedical research. Justifications for such research depend primarily on the important contributions advocates claim it has made toward medical advancements. However, a recent large-scale systematic review indicates that invasive (...) class='Hi'>chimpanzee experiments rarely provide benefits in excess of their profound animal welfare, bioethical and financial costs. The approval of large numbers of these experiments – particularly within the US – therefore indicates a failure of the ethics committee system. By 2008, legislative or policy bans or restrictions on invasive great ape experimentation existed in seven European countries, Japan, Australia and New Zealand. In continuing to conduct such experiments on chimpanzees and other great apes, the US was almost completely isolated internationally. In 2007, however, the US National Institutes of Health National Center for Research Resources implemented a permanent funding moratorium on chimpanzee breeding, which is expected to result in a major decline in laboratory chimpanzee numbers over the next 30 years, as most are retired or die. Additionally, in 2008, The Great Ape Protection Act was introduced to Congress. The bill proposed to end invasive research and testing on an estimated 1,200 chimpanzees confined within US laboratories, and, for approximately 600 federally-owned, to ensure their permanent retirement to sanctuaries. These events have created an unprecedented opportunity for US legislators, researchers, and others, to consider a global ban on invasive chimpanzee research. Such a ban would not only uphold the best interests of chimpanzees, and other research fields presently deprived of funding, but would also increase the compliance of US animal researchers with internationally-accepted animal welfare and bioethical standards. It could even result in the first global moratorium on invasive research, for any non-human species, unless conducted in the best interests of the individual or species. (shrink)
: I respond to an argument presented by Daniel Povinelli and Jennifer Vonk that the current generation of experiments on chimpanzee theory of mind cannot decide whether chimpanzees have the ability to reason about mental states. I argue that Povinelli and Vonk's proposed experiment is subject to their own criticisms and that there should be a more radical shift away from experiments that ask subjects to predict behavior. Further, I argue that Povinelli and Vonk's theoretical commitments should lead them (...) to accept this new approach, and that experiments which offer subjects the opportunity to look for explanations for anomalous behavior should be explored. (shrink)
Purpose: Yerkish is an artificial language created in 1971 for the specific purpose of exploring the linguistic potential of nonhuman primates. The aim of this paper is to remind the research community of some important issues and concepts related to Yerkish that seem to have been forgotten or appear to be distorted. These are, particularly, its success, its promising aspects for future research and last but not least that it was Ernst von Glasersfeld who invented Yerkish: he coined the term (...) “lexigrams,” created the first 120 of them and designed the grammar that regulated their combination. Design: The first part of this paper begins with a short outline of the context in which the Yerkish language originated: the original LANA project. It continues by presenting the language itself in more detail: first, its design, focusing on its “lexigrams” and its “correlational” grammar, and then its use by the chimpanzee Lana in formulating sentences. The second part gives a brief introduction to the foundation of Yerkish in Silvio Ceccato’s Operational Methodology, particularly his idea of the correlational structure of thought and concludes with the main insights that can be derived from the Yerkish experiment seen in the light of Operational Methodology. Findings: Lana’s success in language learning and the success of Yerkish during the past decades are probably due to the characteristics of Yerkish, particularly its foundation in operational methodology. The operation of correlation could be what constitutes thinking in a chimpanzee and an attentional system could be what delivers the mental content that correlation assembles into triads and networks. Research implications: Since no other assessment or explanation of Lana’s performances has considered these foundational issues, a new research project or program should validate the above-mentioned hypotheses, particularly the correlational structure of chimpanzee thinking. (shrink)
Clique sizes for chimpanzee (Pan troglodytes) grooming and for human conversation are compared in order to test Robin Dunbar’s hypothesis that human language is almost three times as efficient a bonding mechanism as primate grooming. Recalculation of the data provided by Dunbar et al. (1995) reveals that the average clique size for human conversation is 2.72 whereas that of chimpanzee grooming is shown to be 2.18. The efficiency of human conversation and actual chimpanzee grooming over Dunbar’s primate (...) grooming model (always one-to-one and a one-way interaction) is 1.27 and 1.25, respectively, when we take role alternation into account. Chimpanzees can obtain about the same efficiency as humans in terms of quantity of social interactions because their grooming is often mutual and polyadic. (shrink)
The question, “Does the chimpanzee have a theory of mind?” is logically identical to the question, “Does the chimpanzee have a soul?” It is a peculiarity of our culture that we talk about anyone having a mind, and such talk is unhelpful for a science of behavior. The label “killjoy hypothesis” is an ad hominem attack.
The relationships between captive primates and their caregivers are critical ones and can affect animal welfare. This study tested the effect of caregivers using chimpanzee behaviors or not, in daily interactions with captive chimpanzees. In the Chimpanzee Behavior condition the caregiver presented chimpanzee behaviors. In the Human Behavior condition the caregiver avoided using chimpanzee behaviors. The chimpanzees had individual patterns of response and had significant differences in their responses to each condition. These data are compared to (...) a similar study conducted at The Zoo Northwest Florida. Both groups of chimpanzees were sensitive and responsive to the differences in conditions. These data suggest ways to improve animal welfare. (shrink)
One of our recent studies has revealed that a numerically trained chimpanzee can memorize a correct sequence of five numbers shown on a monitor. Comparative investigations with humans show very similar patterns of errors in the two species, suggesting humans and chimpanzee share homologous memory processes. Whether or not 5 is a pure capacity limit for the chimpanzee remains an empirical question.
In December 2013, the Nonhuman Rights Project (NhRP) filed a petition for a common law writ of habeas corpus in the New York State Supreme Court on behalf of Tommy, a chimpanzee living alone in a cage in a shed in rural New York (Barlow, 2017). Under animal welfare laws, Tommy’s owners, the Laverys, were doing nothing illegal by keeping him in those conditions. Nonetheless, the NhRP argued that given the cognitive, social, and emotional capacities of chimpanzees, Tommy’s confinement (...) constituted a profound wrong that demanded remedy by the courts. Soon thereafter, the NhRP filed habeas corpus petitions on behalf of Kiko, another chimpanzee housed alone in Niagara Falls, and Hercules and Leo, two chimpanzees held in research facilities at Stony Brook University. Thus began the legal struggle to move these chimpanzees from captivity to a sanctuary, an effort that has led the NhRP to argue in multiple courts before multiple judges. The central point of contention has been whether Tommy, Kiko, Hercules, and Leo have legal rights. To date, no judge has been willing to issue a writ of habeas corpus on their behalf. Such a ruling would mean that these chimpanzees have rights that confinement might violate. Instead, the judges have argued that chimpanzees cannot be bearers of legal rights because they are not, and cannot be persons. In this book we argue that chimpanzees are persons because they are autonomous. (shrink)
This edition presents the first complete English translation of N.N. Ladygina-Kohts' journal chronicling her pioneering work with the chimpanzee, Joni. The journal entries describe and compare the instincts, emotions, play, and habits of her son Rudy and Joni as each develops.
In this brief, we argue that there is a diversity of ways in which humans (Homo sapiens) are ‘persons’ and there are no non-arbitrary conceptions of ‘personhood’ that can include all humans and exclude all nonhuman animals. To do so we describe and assess the four most prominent conceptions of ‘personhood’ that can be found in the rulings concerning Kiko and Tommy, with particular focus on the most recent decision, Nonhuman Rights Project, Inc v Lavery.
From an early age, humans know a surprising amount about basic physical principles, such as gravity, force, mass, and shape. We can see this in the way that young children play, and manipulate objects around them. The same behaviour has long been observed in primates - chimpanzees have been shown to possess a remarkable ability to make and use simple tools. But what does this tell us about their inner mental state - do they therefore share the same understanding to (...) that of a young child? Do they understand the simple, underlying physical principles involved? Though some people would say that they do, this book reports groundbreaking research that questions whether this really is the case. -/- Folk Physics for Apes challenges the assumptions so often made about apes. It offers us a rare glimpse into the workings of another mind, examining how apes perceive and understand the physical world - an understanding that appears to be both similar to, and yet profoundly different from our own. The book will have broad appeal to evolutionary psychologists, developmental psychologists, and those interested in the sub-disciplines of cognitive science (philosophy, anthropology). The book additionally offers for developmental psychologists some valuable new non-verbal techniques for assessing causal understanding in young children. (shrink)
Evolutionary questions require specialized approaches, part of which are comparisons between close relatives. However, to understand the origins of human tool behavior, comparisons with solely chimpanzees are insufficient, lacking the power to identify derived traits. Moreover, tool use is unlikely a unitary phenomenon. Large-scale comparative analyses provide an alternative and suggest that tool use co-evolves with a suite of cognitive traits.
Henrich et al. convincingly caution against the overgeneralization of findings from particular human populations, but fail to apply their own compelling reasoning to our nearest living relatives, the great apes. Here we argue that rearing history is every bit as important for understanding cognition in other species as it is in humans.