Implicit effect of visual long-term memory for nonverbal objects on recognition judgment.

This study uses an indirect recognition procedure to examine whether prior exposure to nonverbal visual objects affects recognition judgments in later, unrelated recognition tests. We also examined the effect of matching operations between study and test on recognition judgments. The experiment consisted of two sessions. The first session was an incidental learning task: Each object was presented twice, and participants were asked to count the number of corners of the presented object. In the second session after 3 weeks, participants performed the same task as in the first session and then performed an unexpected recognition test. In this test, participants were asked to identify whether the presented object had appeared in the second session. To unify the operation between study and test, some participants were required to count the number of corners of the presented object before the recognition judgment. The results revealed that recognition performance for the objects that appeared in the first session was significantly different from that of objects that had not appeared, even when participants were not asked to recall the episode of the first session when performing the recognition test. Although the results of the effect of the matching operation suggested a negative effect on recognition, the results were unclear. This finding indicates that representations for nonverbal objects are preserved for at least 3 weeks. This also highlights the need to consider the implicit effect of a brief prior experience on recognition judgments.