Repeated exposure to an object makes its memory representations larger

Repeated exposure to an object is a common experience in everyday life and behavioral experiments. This study examined whether the memory representations of an object changed after repeated exposure and how such changes could later affect the recall of how many times the object occurred (i.e., frequency). Participants recalled the size of colored dots from short-term memory, and Experiment 1 found that the recalled sizes increased after repeated exposure. Experiments 2a-c found that the increase dissipated with variations in the dots' presentations (i.e., variable positions and backgrounds) and persisted with a reversed response scale, suggesting that the increase resulted from changes in memory representations. Experiment 3 found that consistent increases in an object's recalled sizes predicted better frequency recall, and Experiment 4 manipulated the presented sizes and found that gradual increases led to better frequency recall. These results demonstrated the flexible memory representations of objects after repeated exposure and carried important implications for typical behavioral experiments.