Metacognition in nonhuman primates: a review of current knowledge

In 2006, research on the neurotransmitter serotonin and its transporter protein (5‐HTT) in the synaptic gap celebrated a series of anniversaries. Forty‐five years earlier, presynaptic neurotransmitter uptake was discovered (Hertting & Axelrod, 1961). Two decades later, 5‐HTT was first linked to depression (Langer et al , 1981), shortly after its identification as a target of antidepressant drugs (Raisman et al , 1979). The sequence of the transporter gene from rats was published 10 years after that (Blakely et al , 1991), which initiated an avalanche of molecular genetic studies on the regulation of emotionality. This research culminated in two reports revealing an association between variations of the 5‐HTT gene ( 5‐HTT and SLC6A4 ) and anxiety‐related traits as well as depression (Collier et al , 1996; Lesch et al , 1996). Since then, clinical studies have further supported the link between variants of 5‐HTT and disorders in the regulation of emotion. Although modest effect sizes—typical of non‐Mendelian traits—polygenic patterns of inheritance, epistatic and epigenetic interactions, and heterogeneity between studies confounded the results, 5‐HTT comprises a model molecule for studying gene–environment interactions in cognitive and psychiatric neuroscience. The demonstration in rhesus macaques that stress early in life uniquely reinforces links between variations of 5‐HTT , behaviour and psychopathology seems to herald in a new era of behavioural genetics. Moreover, the discovery that 5‐HTT is a susceptibility gene for depression is a first step towards explaining the molecular dimensions of personality and behaviour, identifying physiological pathways that lead to other disorders of cognitive function and emotion, and analysing the interactive effects of genes and environment in the development of disease. On the heels of these results from behavioural genetics, novel approaches including neurophysiology, neuropsychology and functional neuroimaging, as well as the inclusion of other phenotypes (such as higher cognitive functions, communication skills, social competence and longevity), have …

Chimpanzees infer the location of a reward on the basis of the effect of its weight

The Dawning of Primate Optogenetics

Whereas evidence for metacognition by nonhuman primates has been obtained in great apes and old world monkeys, it is weaker in new world monkeys. For instance, capuchin monkeys may fail to recognize their own knowledge of the location of invisible bait. In the present study, we tested whether tufted capuchin monkeys would flexibly change their behavior in a delayed matching-to-sample (DMTS) test depending upon the strength of their memory trace of the sample. In Experiment 1, two monkeys were tested on a modified 9-alternative DMTS task with various delays on a computerized display. In some trials, the monkeys could choose whether to go for a memory test or for a simple key touch as an escape from the test. In other trials, they were forced to go for the memory test. Both monkeys escaped from the memory test more often when their matching accuracy on forced tests was lower. In one of the monkeys, the matching accuracies on chosen memory tests decreased more slowly as a function of delay length, and were higher after long delays than those on forced memory tests. This suggests that at least one capuchin monkey was able to recognize the strength of his own memory trace. Experiment 2 employed occasional no-sample tests, in which the monkeys faced the task choice without presentation of any sample for the trial. The monkey who was successful in Experiment 1 declined the memory test more often in no-sample trials than regular trials, further indicating metamemory in this individual. In Experiment 3, this successful monkey received a task, in which he was sometimes able to choose between shape MTS or texture MTS tasks. However, his matching accuracies did not differ between chosen tasks and forced tasks. Thus, the metamemory possessed by this new world monkey species may be more like a flag, showing strength of memory trace, than an elaborate representation showing details of the memory trace.

Gaze following is an adaptive skill that might have been selected in social species, such as many nonhuman primates, to obtain information about food location, predators, and social interactions. The authors investigated the ability of spider monkeys (Ateles geoffroyi) and capuchin monkeys (Cebus apella) to follow the gaze of a human around barriers and the presence of "looking back" behavior. In the 1st experiment, a human looked to a target location inside the testing room, whereas in the 2nd experiment, the human looked behind an opaque barrier placed outside the testing room. The authors compared the frequency of looking at the target location with the corresponding baseline looking frequencies. Both species (a) showed evidence of spontaneous gaze following in the 1st experiment and (b) engaged in gaze following behind the barrier in the 2nd experiment. In contrast, neither species performed "looking back" responses. The authors conclude that both monkey species showed some indication of perspective-taking abilities, although the absence of "looking back" behavior suggests a potential difference from the abilities shown by the great apes.

This chapter provides a review of findings from human social cognition based on studies that directly compare humans and non-human primates, particularly great apes (mostly represented by chimpanzees), macaques and capuchin monkeys, along with some speculations about how human social cognition is similar to and different from that of other primates. It focuses on the four themes corresponding to Chapters 2–5: competition and cooperation; social strategies and communication; social learning and culture; and theory of mind and metacognition. The last part of the chapter offers some theoretical speculations about the evolution of human social cognition that emphasizes the cooperative and cultural nature of human beings.

Coffee Oil Consumption Does Not Affect Serum Cholesterol in Rhesus and Cebus Monkeys

Anterior Cingulate Cortex: Unique Role in Cognition and Emotion

A novel hepatitis B virus species discovered in capuchin monkeys sheds new light on the evolution of primate hepadnaviruses

BackgroundUtilization of visual referential cues by non-human primates is a subject of constant scientific interest. However, only few primate species, mostly great apes, have been studied thoroughly in that regard, rendering the understanding of phylogenetic influences on the underlying cognitive patterns difficult.MethodsWe tested six species of captive gibbons in an object-choice task (n = 11) for their ability to interpret two different pointing gestures, a combination of body orientation and gaze direction as well as glancing as referential cues. Hand preferences were tested in the object-choice task and in a bimanual tube task (n = 18).ResultsWe found positive responses to all signals except for the glancing cue at the individual as well as at the group level. The gibbons’ success rates partially exceed results reported for great apes in comparable tests and appear to be similarly influenced by prior exposure to human communicative cues. Hand preferences exhibited by the gibbons in the object-choice task as well as in a bimanual tube task suggest that crested gibbons (Nomascus sp.) are strongly lateralized at individual but not at population level for tasks involving object manipulation.DiscussionBased on the available data, it can be assumed that the cognitive foundations to utilize different visual cues essential to human communication are conserved in extant hominoids and can be traced back at least to the common ancestor of great and lesser apes. However, future studies have to further investigate how the social environment of gibbons influences their ability to exploit referential signals. Gibbons’ manual laterality patterns appear to differ in several aspects from the situation found in great apes. While not extensive enough to allow for general conclusions about the evolution of hand preferences in gibbons or apes in general, our results add to the expanding knowledge on manual lateralization in the Hylobatidae.

Statistical reasoning in nonhuman primates and human children

The Genomic Record of Humankind's Evolutionary Roots

Size isn't everything, comparatively speaking

INTRODUCTION Cognitive capacities may be more highly developed in most primates than among mammals in general (Tomasello & Call 1997), although other mammalian radiations such as cetaceans (e.g., Connor, Smolker & Richards 1992) and birds (e.g., Hunt 1996; Marler 1996) may have evolved similar capacities independently. Numerous studies have also suggested to some that great apes stand out among nonhuman primates in achieving more advanced cognitive abilities (e.g., Byrne 1995; Parker & Gibson 1990; Rumbaugh Savage-Rumbaugh & Washburn 1996; Russon, Bard & Parker 1996). Phenomena such as mirror self-recognition, imitation, pretend play, teaching, and manufacture and flexible use of tools have been cited as evidence that great apes, but not other nonhuman primates, have some form of self-concept, some ability to attribute mental states to others, and greater understanding of physical causality (Byrne 1995, 1997a; Byrne & Whiten 1997; Parker, Chapter 4, this volume; Russon 1997, Chapter 6, this volume; Russon & Bard 1996). Even skeptics note that great apes learn more rapidly than monkeys (Tomasello & Call 1997). Our own recent meta-analysis of published studies on nonhuman primate cognition confirmed this assessment, that great apes are more intelligent than other nonhuman primates (Deaner et al . unpublished). It found that primate cognition is distinguished by some generalized capacity rather than a collection of narrow, problem- or domain-specific abilities, supporting the view that great apes constitute a homogeneous group that outranks other primates in cognitive performance.

In a previous study, chimpanzees, bonobos, orangutans, and capuchin monkeys faced a task that required the use of a rigid stick-like tool to displace an out-of-reach food reward, which was located outside the cage either hanging on a string (e.g., apes) or on a table (e.g., capuchins). Three unfamiliar stick-like tools were placed on a wooden platform for the subjects to choose. Testing consisted of two consecutive trials, each with the same set of tools. Previous to the test subjects learned about the rigidity of the tool either by handling the tools (manipulation), or by observing an experimenter bending and unbending them in sequence (observation); or did not receive any information since the three tools were presented lying on the platform (visual static). In the current study, we investigated whether failing to select the right type of tool in the first trial affected subjects' choices in the second trial. Results showed that when information about the tool rigidity was obtained before selection, great apes and capuchin monkeys changed options in their second choices. However, in the visual static condition, where no information about the rigidity of the tools had been provided before their selection, only great apes discarded wrong tool exemplars in their second trials benefitting from their own mistakes. In contrast, capuchin monkeys did not. We argue that lower attentional focus and lack of stimuli distinctiveness might account for capuchins monkeys' failure to benefit from their own experience. (PsycInfo Database Record (c) 2021 APA, all rights reserved).