I Know What I Saw: Effects of Narrative Overlay on Event Completion and Event Extension

Research has shown that during the memory encoding process, the brain can cognitively fill-in missing visual information causing memory distortions such that people may falsely remember having seen an occluded salient action that occurs either in the middle or at the end of an event. For example, if one were to watch a video of someone kicking a soccer ball, one might falsely remember having seen the foot make contact with the ball even if the video either ended, or cut to the ball flying away, right before the moment of contact. The brain’s ability to fill-in missing visual information occurring in the middle or at the end of a visual stimulus is called event completion and event extension, respectively. Literature on misleading information and social perception suggests these phenomena may be helped by pre-event information overlaying the visual information. Research on event completion and event extension have mainly been conducted using scenes of events that are typical in daily life, such as kicking a ball. The current study investigated both phenomena in a legal context using incomplete video evidence of a burglary taking place. Results suggest that having some pre-event information can increase false memories significantly more than no pre-event information at all. Additionally, being told a full narrative of events before viewing incomplete video evidence may not significantly increase false memory in a recall task. However, those who received the full narrative had marginally more false memories and those who received the label of the crimes the defendant is being charged with had significantly more false memories in a recognition task when compared with control. These results provide the first evidence that full narrative or some additional information prior to watching incomplete video evidence may encourage false memory of having seen things not depicted in video evidence. These results carry implications for how incomplete video evidence is discussed and presented in court as well as future directions for research.