Student Prize Award Abstract
1996 Oral Paper Honorable Mention
A PRELIMINARY REPORT ON FACE RECOGNITION IN CHIMPANZEES (Pan troglodytes)
L.A. Parr1,3, W.D. Hopkins2,3, and F.B.M. de Waal3
1Department of Psycology, Emory University, Atlanta, GA 30322, 2Berry College, Rome, GA 30149, and 3Yerkes Regional Primate Research Center, 954 N. Gatewood Rd., Atlanta, GA 30329, U.S.A.
Five chimpanzees were tested on their ability to
discriminate faces in three separate tasks. Discriminanda
were digitized black & white photographs of unfamiliar
chimpanzee faces with neutral expressions, presented in a
zero-delay matching-to-sample format. Subjects moved a
joystick controlled cursor on a computer monitor to select
one of two laterally presented stimuli that matched a sample
above. First, during initial training four subjects reached
a criterion of >75% correct on 25 identity matching stimulus
sets after <80 trials. Second, an individual recognition
test combined 14 unique stimulus sets, where the correct
pairs were two different photographs of the same individual,
with 10 novel identity matching sets. Subjects performed
significantly above chance on their first exposure to these
24 novel trials indicating their ability to recognize
individuals by face and generalize matching to novel stimuli.
Finally, subjects performed an inversion test involving 10
each of upright and inverted shapes and faces. Four of five
subjects showed a significant impairment in their
discrimination of inverted faces but not of shapes. This
provides the first clear evidence of an inversion effect in
chimpanzees, indicating that face discrimination in this
species may involve a mechanism distinct from that involved
with pattern discrimination.