Cross-fostered as infants in Reno, Nevada, chimpanzees (Pan troglodytes) Wa
shoe, Moja, Tatu, and Dar freely converse in signs of American Sign Languag
e with each other as well as with humans in Ellensburg, Washington. In this
experiment, a human interlocutor waited for a chimpanzee to initiate conve
rsations with her and then responded with 1 of 4 types of probes: general r
equests for more information, on-topic questions, off-topic questions, or n
egative statements. The responses of the chimpanzees to the probes depended
on the type of probe and the particular signs in the probes. They reiterat
ed, adjusted, and shifted the signs in their utterances in conversationally
appropriate rejoinders. Their reactions to and interactions with a convers
ational partner resembled patterns of conversation found in similar studies
of human children.