Memory distortion in inoculated participants.

Abstract

This study investigated the accuracy if memory in participants who had been warned they might be presented with misleading information. Participants were 76 college students from a medium-sized midwestern university. All participants were shown a 12-minute defensive driving video. Three groups of participants were then given either a video, written, or video and written version of the inoculation procedure. The fourth group received no inoculation. All participants were given one of two versions of a post event questionnaire. One version contained 10 accurate questions and 10 misleading questions relating to the defensive driving video. The second version contained 20 accurate questions. One week later participants were given a 40-item forced choice questionnaire. This questionnaire contained 10 critical items that provided a choice between the accurate information contained in the video and the misleading information contained in the post event questionnaire. Ten confirming items provided a choice between accurate information contained in the post event questionnaire and video and information not contained in either the video or the post event questionnaire. The 20 neutral items provided a choice between accurate information contained in the video but not contained in the post event questionnaire and information not included in the video or post event questionnaire. After completing the forced choice questionnaire participants were given a manipulation check to assess the amount of information they retained from the inoculation procedure. Results indicated that participants who were misled and received an inoculation procedure exhibited the greatest memory distortion. The results could indicate a need for a longer inoculation procedure. Future research should examine post event processing in relation to developing a procedure to reduce or prevent memory distortion.