Keith B. Lyle

Long-Term Memory for the Terrorist Attack of September 11: Flashbulb Memories, Event Memories, and the Factors that Influence Their Retention.

More than 3,000 individuals from 7 U.S. cities reported on their memories of learning of the terrorist attacks of September 11, as well as details about the attack, 1 week, 11 months, and/or 35 months after the assault. Some studies of flashbulb memories examining long-term retention show slowing in the rate of forgetting after a year, whereas others demonstrate accelerated forgetting. This article indicates that (a) the rate of forgetting for flashbulb memories and event memory (memory for details about the event itself) slows after a year, (b) the strong emotional reactions elicited by flashbulb events are remembered poorly, worse than nonemotional features such as where and from whom one learned of the attack, and (c) the content of flashbulb and event memories stabilizes after a year. The results are discussed in terms of community memory practices.

Perception and Preference in Short-term Word Priming

Responding optimally with unknown sources of evidence (ROUSE) is a theory of short-term priming applied to associative, orthographic-phonemic, and repetition priming. In our studies, perceptual identification is measured with two-alternative forced-choice testing. ROUSE assumes features activated by primes are confused with those activated by the target. A near-optimal decision discounts evidence arising from such shared features. Too little discounting explains the finding that primed words were preferred after passive viewing of primes. Too much discounting explains the findings of reverse preference after active processing of primes. These preference changes highlight the need to use paradigms (like the present ones) capable of separating preferential and perceptual components of priming. Evidence of enhanced perception was found only with associative priming and was very small in magnitude compared with preference effects.

Importing perceived features into false memories

False memories sometimes contain specific details, such as location or colour, about events that never occurred. Based on the source-monitoring framework, we investigated one process by which false memories acquire details: the reactivation and misattribution of feature information from memories of similar perceived events. In Experiments 1A and 1B, when imagined objects were falsely remembered as seen, participants often reported that the objects had appeared in locations where visually or conceptually similar objects, respectively, had actually appeared. Experiment 2 indicated that colour and shape features of seen objects were misattributed to false memories of imagined objects. Experiment 3 showed that perceived details were misattributed to false memories of objects that had not been explicitly imagined. False memories that imported perceived features, compared to those that presumably did not, were subjectively more like memories for perceived events. Thus, perception may be even more pernicious than imagination in contributing to false memories.

Handedness Is Related to Memory via Hemispheric Interaction: Evidence From Paired Associate Recall and Source Memory Tasks

Strongly right (SR)-handedness is associated with poorer memory performance than nonstrongly right (nSR)-handedness (e.g., Propper, Christman, & Phaneuf, 2005). The hemispheric interaction theory states that the nSR memory advantage occurs because nSR handedness, compared with SR, is a behavioral marker for greater interaction of the cerebral hemispheres. The hemispheric interaction theory predicts that the nSR advantage should be observed exclusively on memory tasks that require hemispheric interaction. The authors tested that prediction by comparing middle-aged and older adults on two memory tasks thought to depend on hemispheric interaction (paired associate recall, source memory) and two thought not to (face recognition, forward digit span). An nSR advantage was more robust for middle-aged than older subjects and, consistent with the hemispheric interaction theory, was found only on the tasks that depend on hemispheric interaction.

Retrieving Essential Material at the End of Lectures Improves Performance on Statistics Exams

At the end of each lecture in a statistics for psychology course, students answered a small set of questions that required them to retrieve information from the same day’s lecture. These exercises constituted retrieval practice for lecture material subsequently tested on four exams throughout the course. This technique is called the PUREMEM (pronounced “pure mem”) procedure for Pure Memory or Practicing Unassisted Retrieval to Enhance Memory for Essential Material. Exam scores were significantly and substantially higher in a section of the course taught with the PUREMEM procedure than one taught without it. Students liked the procedure and believed it increased learning via several different mechanisms.

Eye movements enhance memory for individuals who are strongly right-handed and harm it for individuals who are not.

Subjects who make repetitive saccadic eye movements before a memory test subsequently exhibit superior retrieval in comparison with subjects who do not move their eyes. It has been proposed that eye movements enhance retrieval by increasing interaction of the left and right cerebral hemispheres. To test this, we compared the effect of eye movements on subsequent recall (Experiment 1) and recognition (Experiment 2) in two groups thought to differ in baseline degree of hemispheric interaction—individuals who are strongly right-handed (SR) and individuals who are not (nSR). For SR subjects, who naturally may experience less hemispheric interaction than nSR subjects, eye movements enhanced retrieval. In contrast, depending on the measure, eye movements were either inconsequential or even detrimental for nSR subjects. These results partially support the hemispheric interaction account, but demand an amendment to explain the harmful effects of eye movements for nSR individuals.

Using Popular Films to Enhance Classroom Learning The Good, the Bad, and the Interesting

Popular history films sometimes contain major historical inaccuracies. Two experiments investigated how watching such films influences peoples ability to remember associated texts. Subjects watched film clips and studied texts about various historical topics. Whereas the texts contained only correct information, the film clips contained both correct information (consistent with the text) and misinformation (contradicted by the text). Before watching each clip, subjects received a specific warning, a general warning, or no warning about the misinformation. One week later, they returned for a cued-recall test about the texts. Watching a film clip increased correct recall of consistent information relative to recall of the same information when subjects did not see the clip. However, when the information in the film contradicted the text, subjects often (falsely) recalled misinformation from the film. The specific warning substantially reduced this misinformation effect. Teachers should use popular history films with caution and should warn students about major inaccuracies in the films.

Consistency of Handedness, Regardless of Direction, Predicts Baseline Memory Accuracy and Potential for Memory Enhancement.

Research has shown that consistently right-handed individuals have poorer memory than do inconsistently right- or left-handed individuals under baseline conditions but more reliably exhibit enhanced memory retrieval after making a series of saccadic eye movements. From this it could be that consistent versus inconsistent handedness, regardless of left/right direction, is an important individual difference factor in memory. Or, more specifically, it could be the presence or absence of consistent right-handedness that matters for memory. To resolve this ambiguity, we compared consistent and inconsistent left- and right-handers on associative recognition tests taken after saccades or a no-saccades control activity. Consistent-handers exhibited poorer memory than did inconsistent-handers following the control activity, and saccades enhanced retrieval for consistent-handers only. Saccades impaired retrieval for inconsistent-handers. None of these effects depended on left/right direction. Hence, this study establishes handedness consistency, regardless of direction, as an important individual difference factor in memory.

Age-Related Binding Deficits and the Content of False Memories

The authors examined effects of age-related binding deficits on feature information in false memories for imagined objects (e.g., lollipop) that were similar in shape to seen objects (e.g., magnifying glass). In Experiment 1, location memory for seen objects was lower in older than younger adults and lower still in old-old than young-old adults. Imagined objects, when falsely called seen, were less likely to be attributed to the location of similar seen objects (i.e., congruent attributions) by old-old than young-old adults. In Experiment 2, for younger adults, displaying seen objects for less time (1 s vs. 4 s) reduced both location memory for seen objects and congruent attributions for false memories. Thus, binding deficits may influence the specific content of false memories.

Mechanisms of Source Confusion and Discounting in Short-Term Priming 2: Effects of Prime Similarity and Target Duration

D. E. Huber, R. M. Shiffrin, K. B. Lyle, and K. I. Ruys (2001) tested two-alternative, forced-choice (2-AFC) perceptual identification in a short-term priming task. For repetition priming, passive viewing of primes resulted in a preference to choose repeated words, but actively responding to primes resulted in a preference against choosing repeated words. These results were explained with a computational model, responding optimally with unknown sources of evidence (ROUSE), using the offsetting mechanisms of source confusion and discounting. An analysis of ROUSE revealed conditions under which discounting efficacy should diminish, causing a preference for primed words even with active prime processing. Two new studies confirm 2 such conditions: very short target flash durations and very low similarity between primes and primed choice words. These a priori predictions contrast with the a posteriori data fits of a multinomial model developed by R. Ratcliff and G. McKoon (2001).