Face to Face

Dateline: 06/24/99

Aunts, uncles, brothers, sisters-all humans depend upon visual cues to discern the difference between family members and friends or foes. Many other species depend upon smell or sound to distinguish one individual of the species from another. In groundbreaking research, scientists at the Yerkes Primate Center at Emory University in Atlanta have determined that chimpanzees, like humans, also use a complex set of visual cues to discern related individuals. These completely visual recognition cues are independent of prior experience with an individual.

Previous research had shown that chimpanzees have face recognition capabilities. In this experiment, designed to determine if chimpanzees could match related mothers and offspring, those capabilities were extended. The chimpanzees were shown a picture of a female chimp. That picture was removed and two additional chimps were displayed. One chimp was related to the first female chimp and the other was unrelated but matched for age and sex.

Using a joystick and the digitized images, chimpanzees were able to accurately match the portraits of other chimpanzee mothers and sons. This ability did not, however, extend to pairing either chimpanzee or ape mothers and daughters.

Scientists speculate that due to the male dominated chimpanzee societal structure, discerning the relationship between mothers and sons is more important than discerning female to female relationships. Likewise, in the social structure, females usually move away from the home group while males usually stay. It may be that facial discrimination of males helps the female to avoid groups where the males resemble her mother and thus could very well be related to her. This would cut down on the possibility of inadvertent inbreeding.

This kinship selection is important in that it allows for the propagation of the genetic code. Family members assisting one another helps to improve the chances that the family's genetic line will survive and even thrive.

The data also suggests that the visual cue discrimination abilities of chimpanzees rival those of humans.

What do you think? Are there differences in the visual discrimination cues used by humans and chimpanzees? If so, what are the differences? Come over to the Biology Forum and share your thoughts, opinions, and feelings.

For other information see:

Yerkes Researchers Find Primate Face Recognition Can Be Purely Visual
Information about this study from Science Daily.