Abstract:

Pupils were found to exhibit consistent changing patterns in the same processing stage of different memory tasks, and the changes in pupil size reflect the activation state of the nervous system during information processing. During the pre-coding phase before the stimulus is presented, pupils contract as the individual's endogenous attention level increases. In the information encoding stage, the degree of pupil dilation is used as a bio-marker of the subsequent memory effect, which can predict the memory performance of the future information retrieval stage. In the retrieval phase, when the free recall task is used, pupils contract rapidly with the release of memory load, but the report of each item will cause a small pupil dilation; In the recognition task, pupil dilation is more pronounced when old stimulus is presented than that with new stimulus, producing pupil old/ new effect. Pupil size is a sensitive and stable bio-marker in memory processing. Pupil tracking measurement is an effective approach to explore the physiological mechanism of memory processing. In the future research, pupil tracking along with multiple research methods should be used to further explore the physiological mechanism of memory.

Key words: pupil, memory, subsequent memory effect, pupil old/ new effect, eye tracking