Primates’ Socio-Cognitive Abilities: What Kind of Comparisons Makes Sense?

Abstract

Referential gestures are of pivotal importance to the human species. We effortlessly make use of each others' referential gestures to attend to the same things, and our ability to use these gestures show themselves from very early in life. Almost 20 years ago, James Anderson and colleagues presented an experimental paradigm with which to examine the use of referential gestures in non-human primates: the object-choice task. Since then, numerous object-choice studies have been made, not only with primates but also with a range of other animal taxa. Surprisingly, several non-primate species appear to perform better in the object-choice task than primates do. Different hypotheses have been offered to explain the results. Some of these have employed generalizations about primates or subsets of primate taxa that do not take into account the unparalleled diversity that exists between species within the primate order on parameters relevant to the requirements of the object-choice task, such as social structure, feeding ecology, and general morphology. To examine whether these broad primate generalizations offer a fruitful organizing framework within which to interpret the results, a review was made of all published primate results on the use of gazing and glancing cues with species ordered along the primate phylogenetic tree. It was concluded that differences between species may be larger than differences between ancestry taxa, and it is suggested that we need to start rethinking why we are testing animals on experimental paradigms that do not take into account what are the challenges of their natural habitat.

Ontogeny vs. phylogeny in primate/canid comparisons: A meta-analysis of the object choice task

“…These findings demonstrate that dogs and nonhuman primates are treated systematically differently across the OCT literature. They differ in the quality of their early interactions with humans, they are tested in different physical circumstances, they are tested with different cues to locations presented in different spatial configurations, etc., and these systematic differences have been noted by every extant review of OCT studies (Byrnit, 2015;Lyn, 2010;Mulcahy & Hedge, 2012). Moreover, dogs and nonhuman primates differ in many additional respects, in body plan, in longevity, in the relative durations of successive life history stages, and so on.…”

“…Mulcahy and Hedge (2012) reviewed 63 OCT papers and concluded that configurational differences in the testing of apes and dogs disadvantage the former due to decreased salience of, and attention, to the cue being given. Finally, in a review of gazefollowing OCT studies with nonhuman primates Byrnit (2015) argues that there exists such disparity between different species in their performance on the OCT that taking one species' results as representative of their whole phylogenetic group leads to erroneous conclusions.…”