Testing the role of macaque social tolerance in ability to follow human eye gaze.

Comments on an article by R. Bettle and A. G. Rosati (see record 2022-45647-001). The testing of subjects' abilities to follow human eye gaze has been particularly well studied in nonhuman primates, and this is the question addressed by the Featured Article for this issue by Bettle and Rosati. As described in Bettle and Rosati, he competition hypothesis, stemming from the Machiavellian Intelligence Hypothesis, predicts that species that are more competitive and aggressive will exhibit greater ability to use cues like eye gaze. The tolerance hypothesis, conversely, predicts that species that are more tolerant and affiliative will exhibit greater ability to use these cues. Bettle and Rosati tested Barbary macaques with identical methods. Compared to rhesus macaques, Barbary macaques are relatively tolerant and highly affiliative. Importantly, the authors coded the video-recorded data blind and with high interobserver reliability. The authors found that Barbary macaques were also able to follow human eye gaze: Although roughly half the individuals looked up and followed human's eye gaze in the no barrier condition, only a third looked up in the barrier condition where they could not see what the human was looking at by doing so. These results were quite comparable to the earlier study conducted with rhesus macaques, suggesting that tolerant and less competitive species actually show similar skills. (PsycInfo Database Record (c) 2022 APA, all rights reserved).