Abstract # 5947 Event # 42:

Scheduled for Saturday, September 13, 2014 05:15 PM-05:30 PM: Session 10 (Henry Oliver) Oral Presentation


ARE CHIMPANZEES TRAPPED IN THE "PERMANENT PRESENT?" EVIDENCE FROM FORAGING TASKS

C. R. Menzel and K. Sayers
Georgia State Univ., Language Research Center, Decatur, GA 30034, USA
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     During daily ranging, chimpanzees (Pan troglodytes) are motivated to look at their surroundings and are acute at detecting changes in the layout of resources. An interesting possibility is that chimpanzees notice unripe foods on day 1 and return there on day 1+x when the foods are ripe, based on some form of memory of elapsed time and of whether the foods appreciate or depreciate in value over time. An alternative possibility is that chimpanzees return to food locations based on factors other than temporal cues. For example, an ape may recall the location and state of the food as last seen and discriminate whether it is more profitable than other current alternatives. We review the results of a series of delayed-response experiments that examined memory for temporal information in conjunction with other variables relevant to foraging efficiency. Three captive chimpanzees shown multiple foods in a small forest prioritized their recovery of the hidden foods by proximity, quantity, and quality, in a flexible manner. When the time span of cue giving (showing and hiding the foods) was substantially expanded, they additionally used temporal cues, placing significant weight on the recency of the event [Friedman tests, alpha = .05]. The relative importance attached to recency compared to other variables differed sharply according to the perishability of the objects. Supported by the Leakey Foundation, Wenner-Gren, HD056352 and HD060563.