VS-1: The food bark

In cross-fostering a chimpanzee as if she were a human child, Keith and Cathy Hayes were interested in the nature versus nurture question: How much of our behavior is controlled by our genetic heritage, and how much is due to experience. Here Keith Hayes demonstrates Viki’s “food bark,” a sound she presumably never heard Cathy or Keith make. The food bark must be genetically programmed into a chimpanzee, as Viki had no opportunity to learn this sound from others.

If you listen carefully, you will hear Viki making several other sounds during this short clip. In the beginning of the clip Viki makes a few “alarm calls.” Then she puts her hand over her face to make her “cup” word. At least once she tries this when the ice cream shows up, apparently hoping to get a reward for producing one of her words.