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)

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)

Using an approach developed in the context of human bioethics, we argue that chimpanzees in research can be regarded as vulnerable subjects. This vulnerability is primarily due to communication barriers and situational factors—confinement and dependency—that make chimpanzees particularly susceptible to risks of harm and exploitation in experimental settings. In human research, individuals who are deemed vulnerable are accorded special protections. Using conceptual and moral resources developed in the context of research with vulnerable humans, we show how chimpanzees warrant additional safeguards (...) against harm and exploitation paralleling those for human subjects. These safeguards should include empowering third parties to act as surrogate decision makers for chimpanzees, ensuring participant “assent,” and avoiding recruitment of animal subjects based merely on convenience. (shrink)

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)

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)

This paper considers the question of whether chimpanzees possess at least a primitive sense of normativity: i.e., some ability to internalize and enforce social norms—rules governing appropriate and inappropriate behaviour—within their social groups, and to make evaluations of others’ behaviour in light of such norms. A number of scientists and philosophers have argued that such a sense of normativity does exist in chimpanzees and in several other non-human primate and mammalian species. However, the dominant view in the scientific and philosophical (...) literature is that psychological capacities for social norms evolved uniquely in the human lineage, after our last common ancestor with chimpanzees and bonobos. After reviewing some of the existing evidence for normative capacity in chimpanzees, I defend the thesis of chimpanzee normativity against three key theoretical objections that have been presented in the literature, each of which have played a part in motivating the dominant sceptical position. I argue that, while we still have much to learn about the nature and extent of the normative capacities of other animals, there is strong prima facie evidence for social norms and normative evaluation in chimpanzees and the main theoretical objections to chimpanzee normativity are not at all compelling. (shrink)

There is a persistent methodological problem in primate mindreading research, dubbed the 'logical problem,' over how to determine experimentally whether chimpanzees are mindreaders or just clever behavior-readers of a certain sort. The problem has persisted long enough that some researchers have concluded that it is intractable. The logical problem, I argue, is tractable but only with experimental protocols that are fundamentally different from those that have been currently used or suggested. In the first section, I describe what the logical problem (...) is and how it can, in principle, be solved. In the second section, I illustrate how a well-known experimental protocol by Hare et al. fails to solve the logical problem. In the third section, I do the same for a protocol by Heyes . .) In the fourth section, I describe a novel experimental protocol for visual perspective-taking and argue that it succeeds to discriminate between the relevant mindreading and behavior-reading hypotheses. In addition, this new experimental protocol employs procedures that are realistic enough to suppose that chimpanzees might very well succeed in passing them. (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)

Chimpanzees follow the gaze of conspecifics and humans — follow it past distractors and behind barriers, ‘check back’ with humans when gaze following does not yield interesting sights, use gestures appropriately depending on the visual access of their recipient, and select different pieces of food depending on whether their competitor has visual access to them. Taken together, these findings make a strong case for the hypothesis that chimpanzees have some understanding of what other individuals can and cannot see. However, chimpanzees (...) do not seem nearly so skillful in the Gesture Choice and Object Choice experimental paradigms. Neither behavioral conditioning nor theory of mind explanations can account for these results satisfactorily. Instead this chapter proposes the idea that chimpanzees have the cognitive skills to recall, represent, categorize, and reason about the behavior and perception of others, but not their intentional or mental states, because they do not know that others have such states since they cannot make a link to their own. Human beings began their own evolutionary trajectory with these same skills, but then at some point in their evolution (probably quite recently) they began to understand that their own experience could serve as some kind of model for that of other persons. This allowed for even better prediction and control of the behavior of others and better communication and cooperation with them as well, and so it was an adaptation with immediate adaptive consequences that ensured its survival. (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 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.

Chimpanzee and hunter-gatherer intergroup aggression differ in important ways, including humans having the ability to form peaceful relationships and alliances among groups. This paper nevertheless evaluates the hypothesis that intergroup aggression evolved according to the same functional principles in the two species—selection favoring a tendency to kill members of neighboring groups when killing could be carried out safely. According to this idea chimpanzees and humans are equally risk-averse when fighting. When self-sacrificial war practices are found in humans, therefore, they (...) result from cultural systems of reward, punishment, and coercion rather than evolved adaptations to greater risk-taking. To test this “chimpanzee model,” we review intergroup fighting in chimpanzees and nomadic hunter-gatherers living with other nomadic hunter-gatherers as neighbors. Whether humans have evolved specific psychological adaptations for war is unknown, but current evidence suggests that the chimpanzee model is an appropriate starting point for analyzing the biological and cultural evolution of warfare. (shrink)

Animals react and adjust to the behavior of their conspecifics. Much less is known about whether animals also react and adjust to the psychological states of others. Recent evidence suggests that chimpanzees follow the gaze of others around barriers, past distracters, and check back if they find nothing. Chimpanzees can gauge the motives of a human experimenter and distinguish his intentional from accidental actions. These results suggest that chimpanzees interpret the perceptions and actions of others from a psychological perspective -they (...) seem to know what others can and cannot see and what goals others pursue. It is hypothesized that the co-operation of the ability to operate on psychological states and the motivation to share emotions and experiences with others are key ingredients in the making of human minds. (shrink)

Although chimpanzees have been reported to understand to some extent others' visual perception, previous studies using food requesting tasks are divided on whether or not chimpanzees understand the role of eye gaze. One plausible reason for this discrepancy may be the familiarity of the testing situation. Previous food requesting tasks with negative results used an unfamiliar situation that may be difficult for some chimpanzees to recognize as a requesting situation, whereas those with positive results used a familiar situation. The present (...) study tested chimpanzees' understanding of others' attentional states by comparing two requesting situations: an unfamiliar situation in which food was put on a table, and a familiar situation in which chimpanzees requested food held by an experimenter. Chimpanzees showed evidence of understanding the experimenter's attentional variations and the role of eye gaze only in the latter task. This suggests that an unfamiliar requesting situation may keep subjects from expressing their understanding of others' attentional states even though they are sensitive to them. Keywords: Understanding attention; Social cognition; Chimpanzees. (shrink)

Although chimpanzees have been reported to understand to some extent others’ visual perception, previous studies using food requesting tasks are divided on whether or not chimpanzees understand the role of eye gaze. One plausible reason for this discrepancy may be the familiarity of the testing situation. Previous food requesting tasks with negative results used an unfamiliar situation that may be difficult for some chimpanzees to recognize as a requesting situation, whereas those with positive results used a familiar situation. The present (...) study tested chimpanzees’ understanding of others’ attentional states by comparing two requesting situations: an unfamiliar situation in which food was put on a table, and a familiar situation in which chimpanzees requested food held by an experimenter. Chimpanzees showed evidence of understanding the experimenter’s attentional variations and the role of eye gaze only in the latter task. This suggests that an unfamiliar requesting situation may keep subjects from expressing their understanding of others’ attentional states even though they are sensitive to them. Keywords: Understanding attention; Social cognition; Chimpanzees. (shrink)

Although chimpanzees have been reported to understand to some extent others’ visual perception, previous studies using food requesting tasks are divided on whether or not chimpanzees understand the role of eye gaze. One plausible reason for this discrepancy may be the familiarity of the testing situation. Previous food requesting tasks with negative results used an unfamiliar situation that may be difficult for some chimpanzees to recognize as a requesting situation, whereas those with positive results used a familiar situation. The present (...) study tested chimpanzees’ understanding of others’ attentional states by comparing two requesting situations: an unfamiliar situation in which food was put on a table, and a familiar situation in which chimpanzees requested food held by an experimenter. Chimpanzees showed evidence of understanding the experimenter’s attentional variations and the role of eye gaze only in the latter task. This suggests that an unfamiliar requesting situation may keep subjects from expressing their understanding of others’ attentional states even though they are sensitive to them. Keywords: Understanding attention; Social cognition; Chimpanzees. (shrink)

Literature on the mental capacities and cognitive mechanisms of the great apes has been silent about whether they can act autonomously. This paper provides a philosophical theory of autonomy supported by psychological studies of the cognitive mechanisms that underlie chimpanzee behavior to argue that chimpanzees can act autonomously even though their psychological mechanisms differ from those of humans. Chimpanzees satisfy the two basic conditions of autonomy: (1) liberty (the absence of controlling influences) and (2) agency (self-initiated intentional action), each (...) of which is specified here in terms of conditions of understanding, intention, and self-control. In this account, chimpanzees make knowledge-based choices reflecting a richly information-based and socially sophisticated understanding of the world. Finally, two major theories of autonomy (Kantian theory and two-level theory) are rejected as too narrow to adequately address these issues, necessitating the modifications made in the present approach. (shrink)

Dr. Fouts began his lecture with the story of how he and his wife Deborah became involved with Washoe—the first non-human to acquire the signs of American Sign Language (ASL). Project Washoe began in 1966 with Drs. Allen and Beatrix Gardner in Reno, Nevada. There had been other experiments that attempted to get chimpanzees to speak. These experiments were not successful due to anatomical and neurological differences between humans and chimpanzees. (Fouts showed some video of the chimpanzee Vicki trying (...) to say the four words she had learned—mama, papa, up, cup.) Part of the issue is the construction of the chimpanzee’s vocal box while another part of the issue is that chimpanzee vocalizations are tied to their .. (shrink)

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)

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. Keywords: chimpanzee behavior; animal welfare; species-specific behavior; husbandry. (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)

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.

Following the tradition of comparing humans with chimpanzees placed under unfavorable conditions, the authors suggest many uniquely human technological abilities. However, chimpanzees use spontaneously tools in nature to achieve many different goals demonstrating technological skills and reasoning contradicting the authors contrast. Chimpanzees and humans develop skills through the experiences faced during their upbringing and neglecting this leads to fake conclusions.

There is increasing evidence that some behavioural differences between groups of chimpanzees can be attributed neither to genetic nor to ecological variation. Such differences are likely to be maintained by social learning. While humans teach their offspring, and acquire cultural traits through imitative learning, there is little evidence of such behaviours in chimpanzees. However, by appealing only to incremental changes in motivation, attention and attention-soliciting behaviour, and without expensive changes in cognition, we can hypothesise the possible emergence of imitation and (...) pedagogy in evolutionary history. (shrink)

All known chimpanzee populations have been observed to hunt small mammals for meat. Detailed observations have shown, however, that hunting strategies differ considerably between populations, with some merely collecting prey that happens to pass by while others hunt in coordinated groups to chase fast-moving prey. Of all known populations, Taï chimpanzees exhibit the highest level of cooperation when hunting. Some of the group hunting roles require elaborate coordination with other hunters as well as precise anticipation of the movements of (...) the prey. The meat-sharing rules observed in this community guarantee the largest share of the meat to hunters who perform the most important roles leading to a capture. The learning time of such hunting roles is sometimes especially long. Taï chimpanzee males begin hunting monkeys at about age 10. The hunters’ progress in learning the more sophisticated hunting roles is clearly correlated with age; only after 20 years of practice are they able to perform them reliably. This lengthy learning period has also been shown in some hunter-gatherer societies and confirms the special challenge that hunting represents. (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)