Selected Student/Faculty Research Projects    

Authors: Marisa Adelman,Ed DeLosh, & Shana Carpenter
Title: Tests of the Displaced Rehearsal Explanation of the Spacing Effect
Brief desription: Past research has shown that the spacing effect, the finding that repetitions separated in time or list position are recalled at a higher rate than repetitions presented in immediate succession, is a highly robust phenomenon. Theoretical explanations of the spacing effect remain elusive, however. The current study focuses on one prominent explanation of the spacing effect, the displaced rehearsal hypothesis (cf. Hall, 1992). By this view, when participants are given a mixed list of massed and spaced items, they devote the presentation time for massed repetitions to the rehearsal of earlier items in the list, under the assumption that the massed items have been well learned after the first presentation. This displaced rehearsal results in more rehearsal time for spaced items than massed items, and therefore a memory advantage for spaced items in mixed lists. A key prediction of this hypothesis is that recall for pure massed lists should not differ from recall for pure spaced lists, because in this case, any displaced rehearsal during the presentation of massed repetitions will be devoted to other massed items. Hall’s study supported this view, showing no differences in recall for pure massed versus pure spaced lists, and better memory for early list items in pure massed lists than pure spaced lists. The present study extends on Hall’s work, further examining the displaced rehearsal hypothesis versus other explanations of the spacing effect.

Authors: Julie Bugg, Ed DeLosh, Deana Davalos, & Hasker Davis (University of Colorado, Colorado Springs)
Title: Age Differences in Stroop Interference: Contributions of General Slowing and Task-Specific Deficits
Brief desription: This study examined the contributions of general slowing and task-specific deficits to age-related changes in Stroop interference. 938 participants aged 20 to 89 years completed an abbreviated Stroop color-naming task and a subset of 281 participants also completed card-sorting, simple reaction time, and choice reaction time tasks. Age-related increases in incongruent color-naming latency and card-sorting perseverative errors were observed. Hierarchical regression analyses showed that the processing speed measures accounted for significant variance on both dependent measures, but that there was also a significant residual effect of age. An additional regression analysis showed that some of the variance in incongruent color-naming, after controlling for processing speed, was shared with the variance in perseverative errors. Overall, findings suggest that the age difference in Stroop interference is partially attributable to general slowing, but is also attributable to age-related changes in task-specific processes such as inhibitory control.

Authors: Shana Carpenter & Ed DeLosh
Title: Application of the Testing and Spacing Effects to Name Learning
Brief desription: Four experiments investigated the effects of testing and spacing on the learning of face-name stimulus-response pairs. Experiments 1a and 1b compared the recall of names following intervening tests versus additional study opportunities and found that testing produced better retention of names. Experiments 2 and 3 explored the effects of repeated tests versus study for massed, uniform, or expanded spacing intervals. Tested names were better retained than studied names, spaced names were better retained than massed names, and memory was best for items tested at spaced intervals. Contrary to past findings, expanded schedules did not yield better memory than uniform schedules in either experiment. Theoretical implications for the testing and spacing effects are discussed, along with effective name-learning techniques based on these principles.

Authors: Ben Clegg, Judi Wood, & Julie Bugg
Title: Age-Related Changes in the Planning and Execution of Motor Actions
Brief description: Older and younger adults completed a tapping task using real and imagined movements. Two types of tasks were utilized, linear movements to a single target and sequential movements around a series of targets. Older adults showed a general slowing on all tasks compared to younger adults. More importantly, older adults' performance on the real sequential task only, and not the imagined sequential task, showed increased slowing as target difficulty increased. The results suggest that age-related changes in movement relate specifically to the execution of sequential movements, independent of the planning of such movements.

Authors: Geoff O'Shea & Ben Clegg
Title: Presentation and Response Structure and Implicit Learning
Brief description: The Hebb Digit Task involves short-term memorization of a series of nine digits (1 to 9 in varying orders). Unbeknownst to participants, every third sequence of numbers repeats exactly the same order of items. Improved performance on the repeating pattern compared to random sequences occurs regardless of awareness of the pattern. We sought to examine whether changes to the structure of stimuli and responses would mediate learning. Chunking the sequence during presentation enhanced performance compared to a non-chunked format. Implicit learning was also observed on a continuous performance version of the task.

Authors: Cap Smith (CIS Department), Ben Clegg, & Peter Young (EE Department)
Title: Multi-Modal Support for Augmented Cognition
Brief description: The objective of the research is to determine methods by which multiple sensory modalities can augment human performance during complex tasks. We are specifically interested in compensatory aids for multi-modal perception, and training aids that permit rapid acquisition of expertise.