Edward L. DeLosh

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.

Extrapolation: the sine qua non for abstraction in function learning.

Abstraction was investigated by examining extrapolation behavior in a function-learning task. During training, participants associated stimulus and response magnitudes (in the form of horizontal bar lengths) that covaried according to a linear, exponential, or quadratic function. After training, novel stimulus magnitudes were presented as tests of extrapolation and interpolation. Participants extrapolated well beyond the range of learned responses, and their responses captured the general shape of the assigned functions, with some systematic deviations. Notable individual differences were observed, particularly in the quadratic condition. The number of unique stimulus-response pairs given during training (i.e., density) was also manipulated but did not affect training or transfer performance. Two rule-learning models, an associative-learning model, and a new hybrid model with associative learning and rule-based responding (extrapolation-association model [EXAM]) were evaluated with respect to the transfer data. EXAM best approximated the overall pattern of extrapolation performance.

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.

The bizarreness effect: it's not surprising, it's complex.

Higher recall of bizarre images relative to common images (the bizarreness effect) is consistently found when bizarreness is varied as a within-subject (mixed-list) variable. In Experiment 1, mixed lists, rather than the smaller number of bizarre sentences typically used in such lists, determined the occurrence of the bizarreness effect. Contrary to predictions from expectation-violation theory, Experiments 2 and 3 showed that manipulations designed to augment or attenuate surprise reactions to bizarre sentences had little impact on the bizarreness effect. Experiments 4 and 5 indicated that mixing affected the degree to which participants differentially encoded order information for bizarre and common items. A new account of the bizarreness effect is presented that combines considerations of distinctiveness with the differential use of order information across bizarre and common items.

Order Information and Retrieval Distinctiveness: Recall of Common Versus Bizarre Material

The order-encoding hypothesis (E. L. DeLosh & M. A. McDaniel, 1996) assumes that serial-order information contributes to the retrieval of list items and that serial-order encoding is better for common items than bizarre items. In line with this account, Experiment 1 revealed better free recall and serial-order memory for common than for bizarre items in pure lists, and Experiment 2 showed that recall for bizarre items increased and the recall advantage of common items was eliminated when serial-order encoding for bizarre items was increased to the level of common items. However, inconsistent with a second assumption that bizarre-item advantages in mixed lists reflect better individual-item encoding for bizarre items, Experiments 3 and 4 showed that the bizarreness effect in mixed lists is eliminated when alternative retrieval strategies are encouraged. This set of findings is better explained by the differential-retrieval-process framework, which proposes that contextual factors (e.g., list composition) influence the extent to which various types of information are used at retrieval, with the bizarreness advantage in mixed lists dependent on a distinctiveness-based retrieval process.

Age Differences in Stroop Interference: Contributions of General Slowing and Task-Specific Deficits

ABSTRACT 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.

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

The orderencoding 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 for incidental order-encoding conditions, for longer lists than those used in previous 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 orderencoding account and favor this view over accessibility, interitem association, and cuing effectiveness explanations of the word frequency effect.

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.

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 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.