Recognition of monkey faces by monkey experts

Abstract

Human beings automatically discriminate human faces at the individual level. Infants aged 3 months implicitly recognise monkey faces, but this capacity disappears as recognition skills mature. Expertise is known to affect recognition capacities for different categories of stimuli that are not even face-like in their configuration. We have explored the capacity of adult experts and nonexperts in primatology to recognise monkey faces in both explicit and implicit recognition tasks. In the explicit task, where subjects received the instruction to recognise a face seen previously, experts proved to be more accurate than non-experts. Experts were more affected by inversion than non-experts, suggesting that the processing of those faces is based on their configuration, as is generally observed for human faces. This replicates findings from Diamond and Carey (J Exp Psychol Gen 115:107-117, 1986) in dog experts. In the implicit recognition task, assessed by a visual paired comparison task where no instruction of recognition was given, automatic discrimination was observed for human faces but not for monkey faces. These results suggest that experience acquired by the time of adulthood did not lead the experts to develop recognition skills to the point of matching those exhibited for human faces.

The face inversion effect in non-human primates revisited - an investigation in chimpanzees (Pan troglodytes)

“…Further along the same line, effects of expertise for monkey faces have been tested with a group of expert primatologists, revealing an advantage for experts (as opposed to non-experts) in identifying monkey faces. However, experts were more affected by inversion of monkey faces than non-experts were, suggesting a processing of monkey faces in experts similar to that of human faces51.…”

Visual Phenotype Matching: Cues to Paternity Are Present in Rhesus Macaque Faces

“…Individual monkeys provide a face-like category of stimuli that is no longer discriminated spontaneously by humans beyond the age of 9 months [46], [82], and in explicit recognition tasks adults distinguish unfamiliar human faces more accurately than those of macaques [46], [83]. However, recognition abilities improve if exposure to heterospecifics is accompanied by consistent individuation – infants retain their recognition memory for macaque faces if during exposure each animal is repeatedly referred to by a specific name [84], and trained primate caretakers outperform non-expert adults [83]. Our subjects were significantly better at identifying individual macaques than discerning similarities between pairs of relatives, despite the fact that the individual discrimination task involved the additional processing required to match frontal views with partially rotated faces.…”

Beauty‐related perceptual bias: Who captures the mind of the beholder?

“…Although occasionally the strategy of holistic processing had been reported on other stimuli, such as on monkey faces (Dufour & Petit, 2010), which have been enhanced in other well-defined visual categories (Gauthier & Tarr, 1997), only for faces do such strategies develop without special training.…”