Face perception in monkeys reared with no exposure to faces

Abstract

Infant monkeys were reared with no exposure to any faces for 6 -24 months. Before being allowed to see a face, the monkeys showed a preference for human and monkey faces in photographs, and they discriminated human faces as well as monkey faces. After the deprivation period, the monkeys were exposed first to either human or monkey faces for a month. Soon after, the monkeys selectively discriminated the exposed species of face and showed a marked difficulty in regaining the ability to discriminate the other nonexposed species of face. These results indicate the existence of an experience-independent ability for face processing as well as an apparent sensitive period during which a broad but flexible face prototype develops into a concrete one for efficient processing of familiar faces.deprivation ͉ development ͉ early experience ͉ sensitive period

Rudiments of mind: Insights through the chick model on number and space cognition in animals.

“…It is unfeasible to provide a complete absence of face stimulation even in neonates studied a few hours after birth (Johnson, 2005;Rosa-Salva et al, subm.). Similar limitations are also present with other animals with an altricial pattern of development (e.g., Sugita, 2008). Here is where the importance of comparative studies becomes most readily apparent.…”

The evolution of face processing in primates

“…An infant gibbon, 13 days old (Hylobates agilis) oriented more to face-like compared with non-face-like drawings and by four weeks of age he oriented more towards familiar compared with unfamiliar conspecific's faces [26]. The innate preference of monkeys for looking at faces compared with other visual objects has been strongly supported in a recent study by Sugita [41]. He raised Japanese macaques in face-isolation by having human caregivers wear hoods to conceal their faces while the monkeys' environment was visually enriched.…”

“…He raised Japanese macaques in face-isolation by having human caregivers wear hoods to conceal their faces while the monkeys' environment was visually enriched. Without having ever seen a face, these monkeys preferred to look at faces, both conspecifics and humans, compared with other visual objects [41]. The second type of configural information described by Diamond & Carey [51] is the second-order configuration.…”

“…Although early rearing studies cannot be performed in humans, face-deprivation studies in monkeys addressed the sensitivity of these early periods. Sugita [41] showed that after six months of face-deprivation, the viewing preference and discrimination performance of the monkeys became biased towards the faces of species to which they were first exposed. If they were first shown conspecifics' faces, they showed better discrimination and greater viewing preference for monkey faces compared with human faces or objects.…”

“…Their bias was towards human faces if these were the first faces they were exposed to after the period of face-deprivation. Moreover, these preferences persisted up to a year later even after the monkeys had been given visual exposure to both species [41]. The preference of infant chimpanzees (Pan troglodytes) for their mother's face was present at two months of age, but at one month, the infants showed no preference for their mother's face compared with unrelated individuals [65].…”