One-trial associative memory: comparison of food-storing and nonstoring species of birds

Experiment 1 compared food-storing marsh tits and nonstoring blue tits, and Experiment 2 compared food-storing jays and nonstoring jackdaws, in a one-trial associative memory task, Birds obtained a reward by returning to the site where they had eaten part of the reward 30 min earlier. In “visible” versions, the reward was visible in Phase 1 but hidden in Phase 2 so that the bird had to search for it; in “hidden” versions, the reward was hidden in both phases. No species differences were found in performance in the visible version. However, in the hidden version, the 2 storers preferentially returned to rewarded sites, whereas nonstorers preferentially returned to sites that had been visited in Phase 1, irrespective of whether or not they contained a reward. This suggests that storers differ from nonstorers in the way they discriminate between remembered events.