Adaptive memory: fitness relevant stimuli show a memory advantage in a game of pelmanism.

A pelmanism (matched-pairs) game was used in order to test the hypothesis that survival-relevant stimuli that are likely to have been present during human evolution (e.g., a snake in attack position) enjoy a memory advantage over other survival-relevant (but “modern”) stimuli (e.g., a threatening image of a gunman). Survival-relevant stimuli were matched for arousal and presented in one of two 5 x 4 grids, along with filler items. Participants were asked to match the pairs in the grids by clicking on successive squares to reveal stimuli. Participants made significantly fewer errors when matching evolutionarily relevant survival stimuli than when matching the other stimuli. Additionally, on incorrect trials, the attempted matches were significantly closer to the actual locations of evolutionarily relevant targets than to those of other stimuli. The results suggest that objects that likely posed a consistent threat throughout human evolutionary history are better remembered than other, equally arousing and survival-relevant, stimuli. [corrected]