Children, but not chimpanzees, have facial correlates of determination

Abstract

Facial expressions have long been proposed to be important agents in forming and maintaining cooperative interactions in social groups. Human beings are inordinately cooperative when compared with their closest-living relatives, the great apes, and hence one might expect species differences in facial expressivity in contexts in which cooperation could be advantageous. Here, human children and chimpanzees were given an identical task designed to induce an element of frustration (it was impossible to solve). In children, but not chimpanzees, facial expressions associated with effort and determination positively correlated with persistence at the task. By contrast, bodily indicators of stress (self-directed behaviour) negatively correlated with task persistence in chimpanzees. Thus, children exhibited more behaviour as they persisted, and chimpanzees exhibited less. The facial expressions produced by children, could, therefore, function to solicit prosocial assistance from others.

EquiFACS: The Equine Facial Action Coding System

“…This methodology provides compatible systems that allow direct comparisons using identical techniques across species with a different facial morphology (e.g. [ 14 ]). EquiFACS is the first attempt to develop this system for an animal with laterally placed eyes and an elongated face.…”

Macaques attend to scratching in others

“…This increased attention of the observer towards scratching, and these modulating effects of social relationships, suggest that the macaques were perceiving these behaviours differently from neutral, uninformative postures. Although a social function of stress-associated self-directed behaviour has been suggested (Bradshaw, 1993;Maestripieri et al, 1992;Nakayama, 2004;Waller et al, 2014), these data may represent the first empirical evidence to support this idea.…”

“…Many bird species increase rates of preening in stressful situations, for example when disturbed while resting (Delius, 1988). High rates of scratching follow intense intragroup aggression in macaques, particularly in the victims (Filippo Aureli, van Schaik, & van Hoof, 1989) and chimpanzees, Pan troglodytes, scratch more frequently when the difficulty of cognitive tasks increases (Leavens, Aureli, Hopkins, & Hyatt, 2001) or when frustration is induced through an unsolvable task (Waller, Misch, Whitehouse, & Herrmann, 2014). Thus, in some contexts, there is a demonstrable relationship between stress and self-directed behaviour in animals.…”

“…If so, self-directed behaviours may not just function as a coping mechanism, but could be an important aspect of the social repertoire of some gregarious animals. Specifically within the primates, a communicative function of stress behaviours has been proposed (Bradshaw, 1993;Maestripieri et al, 1992;Nakayama, 2004;Waller et al, 2014), but empirical evidence remains elusive.…”

Facial expression: An under-utilised tool for the assessment of welfare in mammals

“…Shadows can also be cast on the face during different head positions and this may mimic the changes in appearance resulting from muscle since been applied to a number of different nonhuman primates and domesticated species, i.e., chimpanzees , orangutans (Pongo pygmaeus, Caeiro et al, 2012), rhesus macaques (Parr et al, 2010), gibbons and siamangs (Hylobatidae, Waller et al, 2012), horses (Wathan et al, 2015), dogs and cats . This methodology allows direct comparisons using identical techniques across species with a different facial morphology (e.g., Waller et al, 2014). Frequencies and intensities of individual action units and configurations for multiple muscle actions can be analyzed.…”