Understanding Human Perception of Primate Facial Expressions and its Impacts on Human-nonhuman Primate Interactions
Creators: name: Clark, Laura
Publisher: name: University of Lincoln
Year: 2023

description: During wildlife tourism encounters, humans are sensitive to the expressions of non-human primates and often apply inferred felt emotions to them, to provide the interaction with context of how the animal may behave. This can influence how the human may behave towards the animal and an inappropriate interaction can often result in unwanted aggression. This study aims to reduce the amount of unsafe wildlife tourism interactions by exploring if and how human perception of non-human primate facial expressions influences approach behaviour. Using images of Barbary macaques and Capuchin monkeys, two complementary studies were carried out. One focusing on the developmental progression of the human perception of Barbary macaque facial expression and the second exploring different levels of exposure and experience on human perception of and behaviour towards Capuchins in UK and Argentinian natives. For the first study, 81 children and 103 adults were recruited. This study aimed to assess (1) whether human accuracy of facial expression perception is determined by the species perceived (i.e. human and Barbary macaque), type of expression, age, gender, intergenerational effects or behaviour towards animals; (2) whether age, gender and human perception of Barbary macaque facial expressions will influence participant intended proximity to approach, feed or take a selfie with the macaques; (3) If human self-reported behaviour will accurately represent simulated real-life perception of and behaviour towards Barbary macaques. Human perception of Barbary macaque facial expressions did not improve with age as found with human facial expressions, but only improved depending on the type of expression. Participants were more able to accurately perceive neutral, friendly and very aggressive macaque facial expressions than aggressive and distressed ones. No significant differences between the questionnaire and practical task were found for participant ability to accurately perceive distressed, neutral, aggressive or very aggressive Barbary macaque facial expressions. For the second study, a total of 111 participants were recruited. This study aimed to assess (1) whether human accuracy of capuchin facial expression perception is determined by exposure via country of residence, gender or type of capuchin facial expression; (2) whether exposure via country of residence, gender, age and type of expression will influence human intended approach, feed or take a selfie with the capuchins; (3) how perception of and behaviour towards a capuchin will differ between a face only image and face and body image, and how participant experience with capuchins affects this. Argentinians who were novices with respect to encountering capuchins were more accurate in their perception of aggressive capuchin expressions compared to UK novice participants. Argentinian novice participants approached neutral and distressed capuchins closer than UK participants. Both naïve and capuchin-exposed participants were more accurate in their capuchin facial expression recognition when viewing the full face and body image compared to a face only image. Both studies also showed that young males are at greater risk of unsafe human-animal interactions due to their close approaching behaviour and preference for aggressive expressions. The findings from this research can be utilised to make wildlife tourism safer for all ages whilst informing interspecies communication research.