MEMORY OF AUDITORY LISTS BY RHESUS-MONKEYS (MACACA-MULATTA)

Monkey auditory memory was tested with increasing list lengths of 4, 6 , 8, and 10 sounds. Five-hundred and twenty environmental sounds of 3- s duration were used. In Experiment 1, the monkeys initiated each list by touching the center speaker. They touched 1 of 2 side speakers to indicate whether a single test sound (presented from both side speaker s simultaneously) was or was not in the list. The serial-position func tions showed prominent primacy effects (good first-item memory) and re cency effects (good last-item memory). Experiment 2 repeated the proce dure without the list-initiation response and with a variable intertri al interval. The results of both experiments were similar and are disc ussed in relation to theories and hypotheses of serial-position effect s.