Eye movements and implicit source memory

Abstract

During source memory studies, knowledge of some detail about the context of a previously experienced item or event is tested. Here, participants attended to different objects presented at different quadrants on a screen. In a later test phase, a single object was presented in all four quadrants, and participants verbally reported whether the object was new or previously seen (item recognition), and if it was previously seen, they indicated the original screen location (source memory recollection). We combined this test with eye-tracking to determine whether attention to an object during encoding would correlate with later recognition of the object and recall of its source location, and whether eye movements at test can reveal attention to the correct source location in the absence of correct explicit verbal responses. Number of fixations on an object during encoding was not related to later object recognition or source recollection. However, when participants correctly recognised an object but incorrectly indicated the source information, there were significantly more fixations on the correct source location than on incorrect, non-selected locations. Also, when participants correctly recognized an object but said they could not recall the source information, there were significantly more fixations on the correct source location. These findings provide evidence that accurate source information can be expressed through gaze direction even when explicit recollection or verbal expression of that information is incorrect or has failed.