Thinking About Me: How Social Awareness Evolved

—Humans seem unique in their consideration of others’ goals, motivations, intentions, and needs. But the human form of social awareness did not spring from nowhere; certain mechanisms shared across primates formed the foundation from which these processes derived. A review of recent nonhuman primate research points to particular ancestral mechanisms, including an interest in images moving in synchrony with self, a mirror neuron system that responds in the same way to actions made by the self and by others, and inherited social tolerance that provided the bases for social thinking. Still there is a gap in tracking social awareness from these basic beginnings to the ability to think about self and other with respect to intentions and goals. Comparative and clinical work will fill in this gap and will map brain processes onto social thinking

Is a Sense of Inequity an Ancestral Primate Trait? Testing Social Inequity in Cotton Top Tamarins

To address a controversy in the literature concerning whether monkeys show an aversion to inequity, individuals of a New World monkey species, cotton top tamarins (Saguinus oedipus) were tested in an offering task and in a bartering task. At issue was whether the monkeys rejected rewards because of a violation of expectancy of the preferred reward, or whether they rejected rewards because of a sensitivity to socially mediated inequity. The data from both tasks indicated that the subjects were more likely to reject when preferred rewards were presented, either because of another animal eating the reward (the social condition) or because of rewards being presented but inaccessible. The bartering task led to the only behavioral indication of aversion due specifically to social inequity, which was demonstrated when tamarins’ sensitivity to the difference in rewards increased with exposure to other tamarins working to receive the preferred rewards. The results suggest that social inequity aversion will be assessed by tamarins, and possibly by other primates, only under conditions of limited resources and a requirement of work, which may make the situation a bit more competitive and thus drives attention toward both social and reward evaluatio

Face Processing in Humans and New World Monkeys: the Influence of Experiential and Ecological Factors. Animal Cognition

This study tests whether the face-processing sys- tem of humans and a nonhuman primate species share char- acteristics that would allow for early and quick processing of socially salient stimuli: a sensitivity toward conspecific faces, a sensitivity toward highly practiced face stimuli, and an ability to generalize changes in the face that do not sug- gest a new identity, such as a face differently oriented. The look rates by adult tamarins and humans toward conspecific and other primate faces were examined to determine if these characteristics are shared. A visual paired comparison (VPC) task presented subjects with either a human face, chimpanzee face, tamarin face, or an object as a sample, and then a pair containing the previous stimulus and a novel stimulus was presented. The stimuli were either presented all in an upright orientation, or all in an inverted orientation. The novel stim- ulus in the pair was either an orientation change of the same face/object or a new example of the same type of face/object, and the stimuli were shown either in an upright orientation or in an inverted orientation. Preference to novelty scores re- vealed that humans attended most to novel individual human faces, and this effect decreased significantly if the stimuli were inverted. Tamarins showed preferential looking toward novel orientations of previously seen tamarin faces in the up- right orientation, but not in an inverted orientation. Similarly, their preference to look longer at novel tamarin and human faces within the pair was reduced significantly with inverted stimuli. The results confirmed prior findings in humans that novel human faces generate more attention in the upright than in the inverted orientation

Global and Local Processing in Adult Humans (Homo Sapiens), 5-year Old Children (Homo Sapiens), and Adult Cotton Top Tamarins (Saguinus Oedipus)

This study compared adults (Homo sapiens), young children (Homo sapiens), and adult tamarins (Saguinus oedipus) while they discriminated global and local properties of stimuli. Subjects were trained to discriminate a circle made of circle elements from a square made of square elements and were tested with circles made of squares and squares made of circles. Adult humans showed a global bias in testing that was unaffected by the density of the elements in the stimuli. Children showed a global bias with dense displays but discriminated by both local and global properties with sparse displays. Adult tamarins’ biases matched those of the children. The striking similarity between the perceptual processing of adult monkeys and humans diagnosed with autism and the difference between this and normatively developing human perception is discussed

Visual discrimination of male and female faces by infant rhesus macaques

Recent studies have revealed that human infants process female faces differently from male faces. To test whether a similar preference for female faces exists in other primates, we presented nursery-reared infant rhesus macaques with photographs of macaque faces and human faces. At less than 1 month old, infant macaques preferentially oriented towards female macaque faces when faces were presented upright. No preference for female human faces was found. At 9 months old, infants failed to show a visual preference for female macaque faces or female human faces, although they showed significantly more lipsmacking responses at female human faces. Compared to human infants, macaques appear to have stronger predispositions early in life but this preference may nonetheless be amendable to experience. Understanding how innate predispositions and the social rearing environment shape infants’ understanding of faces remain important issues to be explored in order to understand facial processing abilities in humans and other primates

Dog-logic: inferential reasoning in a two-way choice task and its restricted use

Three experiments were designed to test whether adult pet dogs are able to show inferential reasoning when searching for their toy in a series of two-way choice tasks. The experimenter placed a toy under one of two identical containers and then provided some information by manipulating the covers: either both containers were lifted or just the empty or baited one. There were other trials when the experimenter not only revealed the corresponding container but manipulated also the other one without showing its content. In the second experiment the same conditions were used except that the content of the containers was revealed by strings without any human manipulation. Results of the two studies show that dogs are able to use inferential reasoning by exclusion (i.e. they can find the hidden toy if they have seen where the toy was missing). However, dogs were able to solve the reasoning task only when they could not rely on social-communicative cues ( directional gesture and gaze cues) or could not use any other simple discriminative stimuli ( movement of a container) for making decisions. This suggests that dogs are often prevented from showing reasoning abilities by pre-existing biases for social or movement cues. Results of the third experiment also support the primary importance of social cueing because in another object-choice task, individuals preferred to choose the 'socially marked' container ( touching, gaze alternation) to the remotely moved one when they had no visual information about the location of the toy

Tracking of unpredictable moving stimuli by pigeons

Despite being observed throughout the animal kingdom, catching a moving object is a complex task and little is known about the mechanisms that underlie this behavior in non-human animals. Three experiments examined the role of prediction in capture of a moving object by pigeons. In Experiment 1, a stimulus moved in a linear trajectory, but sometimes made an unexpected 90o turn. The sudden turn had only a modest effect on capture and error location, and the analyses suggested that the birds had adjusted their tracking to the novel motion. In Experiment 2, the role of visual input during a turn was tested by inserting disappearances (either 1.5 cm or 4.5 cm) on both the straight and turn trials. The addition of the disappearance had little effect on capture success, but delayed capture location with the larger disappearance leading to greater delay. Error analyses indicated that the birds adapted to the post-turn, post-disappearance motion. Experiment 3 tested the role of visual input when the motion disappeared behind an occluder and emerged in either a straight line or at a 90o angle. The occluder produced a disruption in capture success but did not delay capture. Error analyses indicated that the birds did not adjust their tracking to the new motion on turn trials following occlusion. The combined results indicate that pigeons can anticipate the future position of a stimulus, and can adapt to sudden, unpredictable changes in motion but do so better after a disappearance than after an occlusion

New Caledonian crows rapidly solve a collaborative problem without cooperative cognition

There is growing comparative evidence that the cognitive bases of cooperation are not unique to humans. However, the selective pressures that lead to the evolution of these mechanisms remain unclear. Here we show that while tool-making New Caledonian crows can produce collaborative behavior, they do not understand the causality of cooperation nor show sensitivity to inequity. Instead, the collaborative behavior produced appears to have been underpinned by the transfer of prior experience. These results suggest that a number of possible selective pressures, including tool manufacture and mobbing behaviours, have not led to the evolution of cooperative cognition in this species. They show that causal cognition can evolve in a domain specific manner-understanding the properties and flexible uses of physical tools does not necessarily enable animals to grasp that a conspecific can be used as a social tool