Memory for temporally dynamic scenes

ABSTRACT

Recognition memory was investigated for individual frames extracted from temporally continuous, visually rich film segments of 5–15 min. Participants viewed a short clip from a film in either a coherent or a jumbled order, followed by a recognition test of studied frames. Foils came either from an earlier or a later part of the film (Experiment 1) or from deleted segments selected from random cuts of varying duration (0.5 to 30 s) within the film itself (Experiment 2). When the foils came from an earlier or later part of the film (Experiment 1), recognition was excellent, with the hit rate far exceeding the false-alarm rate (.78 vs. 18). In Experiment 2, recognition was far worse, with the hit rate (.76) exceeding the false-alarm rate only for foils drawn from the longest cuts (15 and 30 s) and matching the false-alarm rate for the 5 s segments. When the foils were drawn from the briefest cuts (0.5 and 1.0 s), the false-alarm rate exceeded the hit rate. Unexpectedly, jumbling had no effect on recognition in either experiment. These results are consistent with the view that memory for complex visually temporal events is excellent, with the integrity unperturbed by disruption of the global structure of the visual stream. Disruption of memory was observed only when foils were drawn from embedded segments of duration less than 5 s, an outcome consistent with the view that memory at these shortest durations are consolidated with expectations drawn from the previous stream.

KEYWORDS:

• Memory
• dynamic
• movie

Acknowledgement

We would like to thank Leila Said for assisting in the collection of data and Bill Mezos for his comments on an earlier draft of the manuscript.

Notes

¹We include analyses that involve type of movie as a variable. Although the wide sampling of movie types was intentionally done, any conclusions regarding movie types or interactions are fraught with numerous confounds. As a result, no conclusions are drawn that reflect performance differences that involved these movies.

²An analysis based on accuracy [(mean hit and correct rejection rate)/2] duplicated the analysis based on signal detection measures, with no differences between mode of presentation (linear = 0.791; jumbled = 0.775), F(1, 52) = 0.77, MSE = .015, η² = .015, p > .20, and no interaction with film, F(2, 104) = 1.17, MSE = .007, η²= .022, p > .20.

³Inconsistencies have been reported, however. Using a somewhat longer film than typical in their research, Zacks et al. (2010) obtained a larger brain response (magnetic resonance, MR, signal change) to fine-grained than coarse events.

⁴This analysis includes an unequal mixture of correct and incorrect reactions across gap size. For example, over 90% of the reactions to lures within gaps of size 0.5 s were called old, and, therefore, separating “old” and “new” responses for correct decisions only was not feasible. As a consequence, this analysis reflects decisional processing, independent of their accuracy.

⁵Temporal jumbling also failed to disproportionally degrade recognition in another condition we have run. In the linear condition, subjects viewed at study only 50 individual frames for 40 ms in the same order as they would appear in the film versus these same frames randomly ordered, followed by the same recognition test as that used in Experiment 1. Performance dropped dramatically but again, overall accuracy was comparable in the “linear” and “jumbled” conditions.

⁶It is possible that even jumbling of a full-length movie would fail to diminish global-processing units. Hollywood movies sometimes use jumbling to embellish artistic presentation. For example, the protagonist in the movie “Memento” attempts to solve a murder even though he has suffered hippocampal damage. In the film, scenes are presented in a confusing array of temporal events (with segments occasionally repeating), mimicking the mind of the protagonist. Although bewildering at first, the viewer has little difficulty piecing the segments together into a coherent story.