Remembering more than meets the eye: A study of memory confusions about incomplete visual information

Abstract

The purpose of this series of four experiments was to examine the possible role of spontaneous imagery in memory confusions about the way in which visual information had been experienced. After viewing pictures of familiar objects, complete or incomplete in visual form, participants were asked to remember the way in which the objects had been presented. Although, as predicted, memory for the objects themselves was quite good, participants falsely remembered seeing complete versions of pictures that were actually presented as incomplete. These false reports were observed across a variety of encoding and testing conditions. The results suggest that the false reports (referred to here as completion errors) are due to internal representations based on filling-in processes in response to the encoding of incomplete visual information. As such, the results also speak to alternative explanations for the completion errors and, more broadly, to theoretical perspectives that draw on filling-in processes when accounting for object identification and object memory.

Notes

¹We are in agreement with the suggestion that care must be taken when examining differential effects of various task features on different memory measures such as item and source memory (e.g., Henkel & Franklin, 1998; Murnane & Bayen, 1996). Under these conditions, assessing item memory independently of source judgements (simply asking some participants to decide whether or not a picture was presented during an encoding series) is imperative (e.g., Foley & Foley, 2007). However, as we noted, assessing the basis of the completion error is far less complicated when overall recognition accuracy levels are uniformly high.

²The computation of the source accuracy measure reported in this paper is the most frequently used measure (Johnson et al., 1993). In this case, the source measure weights the number of pictures correctly classified (as complete or incomplete) by the number of pictures correctly recognised as old. This technique can inflate the accuracy estimates if the overall level of recognition is relatively poor. For example, if recognition levels are 70% accurate but all of the pictures are correctly classified, source accuracy scores will be relatively high. Potential variation in levels of recognition led to the creation of alternative techniques for assessing source accuracy (Batchelder & Reifer, 1990; Murnane & Bayen, 1996). Essentially this correction controls for the possibility of inflated source accuracy scores in the presence of relatively low item recognition. In the present studies, item recognition was quite good, and importantly did not differ systematically for pictures presented complete or incomplete.

³In Experiment 3, the way in which visual information was removed was manipulated using deletion or occlusion. This manipulation was intended to affect impressions of encounter (Kanizsa & Gerbino, 1982). However, because there was no effect for this manipulation, nor any interaction involving this factor, for the sake of brevity, we did not report this manipulation in any detail.