Mnemonic benefits of retrieval practice at short retention intervals.

The testing effect refers to the retention benefit conferred by prior retrieval of information from memory. Although the testing effect is a robust phenomenon, a common assumption is that reliable memory benefits only emerge after long retention intervals of days or weeks. The present study focused on potential test-induced retention benefits for brief retention intervals on the order of minutes and tens of seconds. Participants in four experiments studied lists of words. Some of the items were subjected to an initial cued recall test, and others were re-presented for additional study. Free recall tests were administered in each experiment following retention intervals ranging from 30 s to 8 min. When initial retrieval practice was successful (Experiments 1 through 3), or feedback compensated for unsuccessful retrieval (Experiment 4), significant testing effects emerged at all retention intervals. Results are discussed in the context of a bifurcated item-distribution model and highlight the importance of initial test performance and the type of analysis employed when examining testing effect data.

On the reliability of retrieval-induced forgetting.

Memory is modified through the act of retrieval. Although retrieving a target piece of information may strengthen the retrieved information itself, it may also serve to weaken retention of related information. This phenomenon, termed retrieval-induced forgetting, has garnered substantial interest for its implications as to why forgetting occurs. The present study attempted to replicate the seminal work by Anderson et al. (1994) on retrieval-induced forgetting, given the apparent sensitivity of the effect to certain deviations from the original paradigm developed to study the phenomenon. The study extends the conditions under which retrieval-induced forgetting has been examined by utilizing both a traditional college undergraduate sample (Experiment 1), along with a more diverse internet sample (Experiment 2). In addition, Experiment 3 details a replication attempt of retrieval-induced forgetting using Anderson and Spellman's (1995) independent cue procedure. Retrieval-induced forgetting was observed when using the traditional retrieval practice paradigm with undergraduate (Experiment 1) and internet (Experiment 2) samples, though the effect was not found when using the independent cue procedure (Experiment 3). Thus, the study can provide an indication as to the robustness of retrieval-induced forgetting to deviations from the traditional college undergraduate samples that have been used in the majority of existing research on the effect.

Testing effects in mixed- versus pure-list designs.

In the present study, we investigated the role of list composition in the testing effect. Across three experiments, participants learned items through study and initial testing or study and restudy. List composition was manipulated, such that tested and restudied items appeared either intermixed in the same lists (mixed lists) or in separate lists (pure lists). In Experiment 1, half of the participants received mixed lists and half received pure lists. In Experiment 2, all participants were given both mixed and pure lists. Experiment 3 followed Erlebacher's (Psychological Bulletin, 84, 212-219, 1977) method, such that mixed lists, pure tested lists, and pure restudied lists were given to independent groups. Across all three experiments, the final recall results revealed significant testing effects for both mixed and pure lists, with no reliable difference in the magnitude of the testing advantage across list designs. This finding suggests that the testing effect is not subject to a key boundary condition-list design-that impacts other memory phenomena, including the generation effect.

Benefits of testing for nontested information: retrieval-induced facilitation of episodically bound material.

Testing is a powerful means to boost the retention of information. The extent to which the benefits of testing generalize to nontested information, however, is not clear. In three experiments, we found that completing cued-recall tests for a subset of studied materials enhanced retention for the specific information tested, as well as for associated, nontested information during later free-recall testing. In Experiment 1, this generalized benefit was revealed for lists of category-exemplar pairs. Experiment 2 extended the effect to unrelated words, suggesting that retrieval can enhance later free recall of nontested information that is bound solely through episodic context. In Experiment 3, we manipulated the format of the final test and found facilitation in free-recall, but not in cued-recall, testing. The results suggest that testing may facilitate later free recall in part by enhancing access to information that is present during a prior temporal or list context. More generally, these findings suggest that retrieval-induced facilitation extends to a broader range of conditions than has previously been suggested, and they further motivate the adoption of testing as a practical and effective learning tool.

Testing effects for common versus proper names.

The present study examines the testing effect as a function of item meaningfulness. In Experiments 1 and 2 participants studied lists of words that could serve as proper names or occupations (e.g., Mr Baker or baker), with the items given in a name context for one group and an occupation context for a second group. During an intervening phase participants restudied some items and were given a cued recall test (Experiment 1) or a free recall test (Experiment 2) on other items. On a final free recall test memory was better for tested items than studied items in both the name and occupation contexts. Experiment 3 followed the same procedure as Experiment 1, except that participants studied lists of proper names that do not have alternative uses in the English language (e.g., Mr Anderson) or studied concrete nouns (e.g., letter). Tested items were better remembered on a final test than studied items, and there was no interaction with type of study material. These results show that the testing effect extends to proper names, material that is commonly assumed to differ from common names on several dimensions.

Age differences in Stroop interference: contributions of general slowing and task-specific deficits.

This study examined the contributions of general slowing and task-specific deficits to age-related changes in Stroop interference. Nine hundred thirty-eight 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.

Physical activity moderates time-of-day differences in older adults' working memory performance.

Based on a synthesis of the literature on time of day and physical fitness effects on cognition, the current study examined whether physical activity moderated time-of-day differences in older adults' performance on a working memory task. Sedentary older adults' working memory performance declined significantly from morning to evening, whereas more active older adults performed similarly across the day. This interaction did not extend to performance on a simple reaction time task. A novel explanation based on the selective effect of mental fatigue on executive control processes is proposed.

Impoverished cue support enhances subsequent retention: support for the elaborative retrieval explanation of the testing effect.

In three experiments, we investigated the role of transfer-appropriate processing and elaborative processing in the testing effect In Experiment 1, we examined whether the magnitude of the testing effect reflects the match between intervening and final tests by factorially manipulating the type of intervening and final tests. Retention was not enhanced for matching, relative to mismatching, intervening and final tests, contrary to the transfer-appropriate-processing view. In Experiment 2, we examined final retention as a function of the number of cues needed to retrieve items on intervening cued recall tests. In this case, fewer retrieval cues were associated with better memory on the final test. Experiment 3 replicated the findings of Experiment 2 while controlling for individual item difficulty and directly manipulating the number of cues present. These findings suggest that an intervening test may be most beneficial to final retention when it provides more potential for elaborative processing

Age differences in fluid intelligence: contributions of general slowing and frontal decline.

The current study examined the contributions of general slowing and frontal decline to age differences in fluid intelligence. Participants aged 20-89 years completed Block Design, Matrix Reasoning, simple reaction time, choice reaction time, Wisconsin Card Sorting, and Tower of London tasks. Age-related declines in fluid intelligence, speed of processing, and frontal function were observed. Hierarchical regression analyses showed that the processing speed and frontal function measures accounted for significant variance in fluid intelligence performance, but there was also a residual effect of age after controlling for each variable individually as well as both variables. An additional analysis showed that the variance in fluid intelligence that was attributable to processing speed was not fully shared with the variance attributable to frontal function. These findings suggest that the age-related decline in fluid intelligence is due to general slowing and frontal decline, as well as other unidentified factors.

Effects of word frequency on individual-item and serial order retention: tests of the order-encoding view.

The order-encoding view of the word frequency effect proposes that low-frequency (LF) items attract more attention to the encoding of individual-item information than do high-frequency (HF) items, but at the expense of order encoding (DeLosh & McDaniel, 1996). When combined with the assumption that free recall of unrelated words is organized according to their original order of presentation, this view explains the finding that HF words are better recalled than LF words in pure lists but that, in mixed lists, recall is better for LF words. The present study confirmed that in mixed lists, order memory becomes equivalent for HF and LF words and that the predicted pattern of order memory and recall holds fo r incidental order-encoding conditions, for longerlists than those used inprevious experiments, and for lists with minimal interitem associativity. Moreover, recall from HF lists declined, but recall from LF lists improved, in related-word lists, relative to unrelated-word lists, reversing the usual pure-list free recall advantage for HF words. These results were uniquely predicted by the order-encoding account and favor this view over accessibility, interitem association, and cuing effectiveness explanations of the word frequency effect.

Working memory, inhibition, and fluid intelligence as predictors of performance on Tower of Hanoi and London tasks.

The contributions of working memory, inhibition, and fluid intelligence to performance on the Tower of Hanoi (TOH) and Tower of London (TOL) were examined in 85 undergraduate participants. All three factors accounted for significant variance on the TOH, but only fluid intelligence accounted for significant variance on the TOL. When the contribution of fluid intelligence was accounted for, working memory and inhibition continued to account for significant variance on the TOH. These findings support argument that fluid intelligence contributes to executive functioning, but also show that the executive processes elicited by tasks vary according to task structure.