Biomedical subjects
Publications and source records attributed to E W Menzel.
Infant chimpanzees, after watching a small black-and-white closed-circuit television picture of a familiar caretaker walking out into an outdoor field and disappearing from sight, were more successful in finding the person than if they had been given no such cue; and their performance approximated that which obtained after they had seen the same scene normally, via direct perception.
The characteristic calls of Saguinus fuscicollis are described and illustrated with sound spectrograms. Each call type and its associated behavior is listed together with motor and vocal responses usually observed for a given context. Many of the call types are highly specific to social contexts while others appear to reflect changes in excitation level. Call types form two categories when related according to their acoustic structural similarity. Information in the 'group vocabulary" is discussed under five functional categories: spatial cohesion; alerting; aggressive behavior; infant calls, and adult vocalization during infant calls.
The rate at which a chimpanzee approaches a hidden, distant goal varies according to social conditions and according to whether the goal is a novel object or food. This behavior furnishes a social group with sufficient information for simultaneous and successive disrciminations between leaders and between goals.