Abstract
Prospective memory is remembering to do something at a future time. A growing body of research supports that prospective memory may exist in nonhuman animals, but the methods used to test nonhuman prospective memory differ from those used with humans. The current work tests prospective memory in chimpanzees using a method that closely approximates a typical human paradigm. In these experiments, the prospective memory cue was embedded within an ongoing task. Tokens representing food items could be used in one of two ways: in a matching task with pictures of items (the ongoing task) or to request a food item hidden in a different location at the beginning of the trial. Chimpanzees had to disengage from the ongoing task in order to use the appropriate token to obtain a higher preference food item. In Experiment 1, chimpanzees effectively matched tokens to pictures, when appropriate, and disengaged from the ongoing task when the token matched the hidden item. In Experiment 2, performance did not differ when the target item was either hidden or visible. This suggested no effect of cognitive load on either the prospective memory task or the ongoing task, but performance was near ceiling, which may have contributed to this outcome. In Experiment 3, we created a more challenging version of the task. More errors on the matching task occurred before the prospective memory had been carried out, and this difference seemed to be limited to the hidden condition. This finding parallels results from human studies and suggests that working memory load and prospective memory may have a similar relationship in nonhuman primates.
Highlights
Prospective memory (PM) is the formation, storage, retrieval, and implementation of an intended future action – or, more succinctly, it is remembering to do something later
Because the chimpanzees had not used these lexigram tokens to request actual food items for over a year, and because they had just been encouraged to use them in an entirely new context, we presented each chimpanzee with a short series of sessions to reacquaint them with the token request procedure within this new context
Each chimpanzee disengaged from the matching task and exchanged an appropriate token for the target food item in most sessions (Lana: 75% of sessions; Panzee: 75% of sessions; Sherman: 83.33% sessions)
Summary
Prospective memory (PM) is the formation, storage, retrieval, and implementation of an intended future action – or, more succinctly, it is remembering to do something later. PM may be even more evident when it fails us, for example, when a man forgets that his wife asked him to pick up something from the market on the way home or when one fails to mail a bill payment before the due date This psychological phenomenon has become well studied in the past three decades using both highly controlled laboratory tests and more naturalistic ‘‘real-world’’ scenarios [1], [2], [3]; for a review, see [4]. The interval between the intention formation and onset of the task varies across studies from immediate presentation of the unrelated task, e.g. [7], to hours later, e.g. [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
