Covert Retrieval Research Articles

BOLD Activity During Correct-Answer Feedback in Cued Recall Predicts Subsequent Retrieval Performance: An fMRI Investigation Using a Partial Trial Design.

Receiving correct answer feedback following a retrieval attempt has proven to be a highly effective means of learning new information, yet the mechanisms behind its efficacy remain poorly understood. Here, fMRI was used to examine how BOLD activity measured during a period of feedback could predict subsequent memory (SM) performance on a final test. Twenty-five human subjects studied pairs of associated words, and were then asked to covertly recall target words in response to provided cues. Correct answer feedback was provided immediately after covert retrieval attempts. A partial trial design enabled separate modeling of activity related to retrieval and to feedback processing. During initial study, typical SM effects were observed across the whole brain. During feedback following a failed recall attempt, activity in only a subset of these regions predicted final test performance. These regions fell within the default mode network (DMN) and demonstrated negative SM effects, such that greater deactivation was associated with successful recall. No "task-positive" regions demonstrated SM effects in this contrast. The obtained results are consistent with a growing literature that associates DMN deactivation with successful learning in multiple task contexts, likely reflecting differences in the allocation of attentional resources during encoding.

Test-potentiated learning: three independent replications, a disconfirmed hypothesis, and an unexpected boundary condition

ABSTRACTArnold and McDermott [(2013). Test-potentiated learning: Distinguishing between direct and indirect effects of testing. Journal of Experimental Psychology: Learning, Memory, and Cognition, 39, 940–945] isolated the indirect effects of testing and concluded that encoding is enhanced to a greater extent following more versus fewer practice tests, referred to as test-potentiated learning. The current research provided further evidence for test-potentiated learning and evaluated the covert retrieval hypothesis as an alternative explanation for the observed effect. Learners initially studied foreign language word pairs and then completed either one or five practice tests before restudy occurred. Results of greatest interest concern performance on test trials following restudy for items that were not correctly recalled on the test trials that preceded restudy. Results replicate Arnold and McDermott (2013) by demonstrating that more versus fewer tests potentiate learning when trial time is limited. Results also provide strong evidence against the covert retrieval hypothesis concerning why the effect occurs (i.e., it does not reflect differential covert retrieval during pre-restudy trials). In addition, outcomes indicate that the magnitude of the test-potentiated learning effect decreases as trial length increases, revealing an unexpected boundary condition to test-potentiated learning.

Assessing Boundary Conditions of the Testing Effect: On the Relative Efficacy of Covert vs. Overt Retrieval.

Repeated testing during learning often improves later memory, which is often referred to as the testing effect. To clarify its boundary conditions, we examined whether the testing effect was selectively affected by covert (retrieved but not articulated) or overt (retrieved and articulated) response format. In Experiments 1 and 2, we compared immediate (5 min) and delayed (1 week) cued recall for paired associates following study-only, covert, and overt conditions, including two types of overt articulation (typing and writing). A clear testing effect was observed in both experiments, but with no selective effects of response format. In Experiments 3 and 4, we compared covert and overt retrieval under blocked and random list orders. The effect sizes were small in both experiments, but there was a significant effect of response format, with overt retrieval showing better final recall performance than covert retrieval. There were no significant effects of blocked vs. random list orders with respect to the testing effect produced. Taken together, these findings suggest that, under specific circumstances, overt retrieval may lead to a greater testing effect than that of covert retrieval, but because of small effect sizes, it appears that the testing effect is mainly the result of retrieval processes and that articulation has fairly little to add to its magnitude in a paired-associates learning paradigm.

Functional activation independently contributes to naming ability and relates to lesion site in post-stroke aphasia.

Language network reorganization in aphasia may depend on the degree of damage in critical language areas, making it difficult to determine how reorganization impacts performance. Prior studies on remapping of function in aphasia have not accounted for the location of the lesion relative to critical language areas. They rectified this problem by using a multimodal approach, combining multivariate lesion-symptom mapping and fMRI in chronic aphasia to understand the independent contributions to naming performance of the lesion and the activity in both hemispheres. Activity was examined during two stages of naming: covert retrieval, and overt articulation. Regions of interest were drawn based on over- and under-activation, and in areas where activity had a bivariate relationship with naming. Regressions then tested whether activation of these regions predicted naming ability, while controlling for lesion size and damage in critical left hemisphere naming areas, as determined by lesion-symptom mapping. Engagement of the right superior temporal sulcus (STS) and disengagement of the left dorsal pars opercularis (dPOp) during overt naming was associated with better than predicted naming performance. Lesions in the left STS prevented right STS engagement and resulted in persistent left dPOp activation. In summary, changes in activity during overt articulation independently relate to naming outcomes, controlling for stroke severity. Successful remapping relates to network disruptions that depend on the location of the lesion in the left hemisphere. Hum Brain Mapp 38:2051-2066, 2017. © 2017 Wiley Periodicals, Inc.

Does Covert Retrieval Benefit Learning of Key-Term Definitions?

Even though retrieval practice typically has a robust, positive influence on memory, response format (overt vs. covert retrieval) may moderate its effect when students learn complex material. Overt retrieval is likely to promote exhaustive retrieval, whereas covert retrieval may not be exhaustive for familiar key terms. In two experiments, students were instructed to study key-term definitions and were asked to practice retrieval overtly, to practice retrieval covertly, or to restudy the definitions. Students also made metacognitive judgments. A final criterion test was administered two days later. Students’ final recall was greater after overt retrieval practice than after covert retrieval practice or restudy, with a continuously cumulating meta-analysis establishing the effect as moderate in size (pooled d = 0.43). Thus, response format does matter for learning definitions of key terms, supporting the recommendation that students use overt retrieval when using retrieval practice as a strategy to learn complex materials.

The Influence of Retrieval Practice Versus Delayed Judgments of Learning on Memory: Resolving a Memory-Metamemory Paradox.

The positive effect of delayed retrieval practice on subsequent test performance is robust; by contrast, making delayed judgments of learning (JOLs) encourages covert retrieval but has a minor influence on final test performance. In three experiments, we experimentally established and explored this memory-metamemory paradox. After initial study of paired associates (e.g., husky - ram), participants either were explicitly tested (husky - ?) or made a JOL. In Experiment 1, we adopted the standard JOL method, using a short retention interval, whereas in Experiments 2 and 3, we used a common testing-effect method involving a longer retention interval. Delayed JOLs did not boost test performance, but explicit delayed tests boosted memory after a longer retention interval. As important, participants spent less time to make JOLs than to retrieve responses. These data indicate that differences in the dynamics of retrieval for practice tests versus delayed JOLs are responsible for the paradox.

Covert retrieval practice benefits retention as much as overt retrieval practice.

Many experiments provide evidence that practicing retrieval benefits retention relative to conditions of no retrieval practice. Nearly all prior research has employed retrieval practice requiring overt responses, but a few experiments have shown that covert retrieval also produces retention advantages relative to control conditions. However, direct comparisons between overt and covert retrieval are scarce: Does covert retrieval-thinking of but not producing responses-on a first test produce the same benefit as overt retrieval on a criterial test given later? We report 4 experiments that address this issue by comparing retention on a second test following overt or covert retrieval on a first test. In Experiment 1 we used a procedure designed to ensure that subjects would retrieve on covert as well as overt test trials and found equivalent testing effects in the 2 cases. In Experiment 2 we replicated these effects using a procedure that more closely mirrored natural retrieval processes. In Experiment 3 we showed that overt and covert retrieval produced equivalent testing effects after a 2-day delay. Finally, in Experiment 4 we showed that covert retrieval benefits retention more than restudying. We conclude that covert retrieval practice is as effective as overt retrieval practice, a conclusion that contravenes hypotheses in the literature proposing that overt responding is better. This outcome has an important educational implication: Students can learn as much from covert self-testing as they would from overt responding.

Does response mode affect amount recalled or the magnitude of the testing effect?

The testing effect is the finding that retrieval practice can enhance recall on future tests. One unanswered question is whether first-test response mode (writing or speaking the answer) affects final-test performance (and whether final-test response mode itself matters). An additional unsettled issue is whether written and oral recall lead to differences in the amount recalled. In three experiments, we examined these issues: whether subjects can recall more via typing or speaking; whether typing or speaking answers on a first test can lead to better final-test performance (and whether an interaction occurs with final-test response mode) and whether any form of overt response leads to better final-test performance as compared to covert retrieval (thinking of the answer but not producing it). Subjects studied paired associates; took a first test by typing, speaking, or thinking about responses; and then took a second test in which the answers were either spoken or typed. The results revealed few differences between typing and speaking during recall, and no difference in the size of the testing effect on the second test. Furthermore, an initial covert retrieval yielded roughly the same benefit to future test performance as did overt retrieval. Thus, the testing effect was quite robust across these manipulations. The practical implication for learning is that covert retrieval provides as much benefit to later retention as does overt retrieval and that both can be effective study strategies.

Study for now, but judge for later: Delayed judgments of learning promote long‐term retention

Delayed judgments of learning (JOL) are assumed to be based on covert retrieval attempts. A common finding is that testing memory during learning improves later retention (i.e., the testing effect), and even more so than an equivalent amount of study, but only after a longer retention interval. To test the assertion that also delayed JOLs improve memory, the participants either studied Swahili-Swedish word pairs four times, or they both studied (two times) and performed delayed JOLs (two times) alternately. Final cued recall test were given after either five minutes or one week. Results showed a reliable learning-group by retention-interval interaction, with less forgetting in the group that alternated between studying and making JOLs. The results are discussed in relation to the self-fulfilling prophecy account of Spellman and Bjork (1992), and in terms of study advice, the results further underscore the importance of delaying JOLs when studying and evaluating one's ongoing learning.

The Testing Effect as a Function of Explicit Testing Instructions and Judgments of Learning

During study, people monitor their learning; the output of this monitoring is captured in so-called judgments of learning (JOLs). JOLs predict later recall better if they are made after a slight delay, instead of immediately after study (the delayed JOL effect). According to the self-fulfilling prophecy (SFP) hypothesis delayed JOLs are based on covert retrieval attempts from long-term memory, and successful retrieval attempts in themselves enhance learning (the testing effect). We compared memory for 40 Swahili-Swedish paired associates after a week as a function of three different learning conditions, namely study plus (i) explicitly instructed self-testing, (ii) delayed JOLs, or (iii) less self-testing. We showed that repeated delayed JOLs lead to a memory improvement that does not differ significantly from a comparable condition where the participants are explicitly testing memory, and both the latter groups performed reliably better than a group that self-tested less. The results suggest that delayed JOLs improve long-term retention as efficiently as explicit memory testing and lend support to the SFP hypothesis.

The role of covert retrieval in working memory span tasks: Evidence from delayed recall tests

The current study examined delayed recall of items that had been processed during simple and complex span tasks. Three experiments were reported showing that despite more items being recalled initially from a simple span task (i.e., word span) than a complex span task (i.e., operation span), on a delayed recall test more items were recalled that had initially been processed during the complex span task. This delayed recall advantage for items processed during complex span tasks persisted when subjects were encouraged to process the items deeply during the initial span task (Experiment 2), and when initial recall during the span task was precluded (Experiment 3). The covert retrieval model explains these data as being the result of subjects maintaining items in working memory during complex span tasks by covertly retrieving them during the processing phases of the tasks. These covert retrieval attempts provide distributed practice retrieving items from long-term memory, creating effective retrieval cues for later delayed recall that are not created during simple span tasks. The covert retrieval model was supported by data showing that words presented in earlier serial positions during operation span, which had the greatest likelihood of being covertly retrieved, were most likely to be recalled on the delayed recall test. These data support the notion that complex working memory span tasks share considerable processing overlap with episodic memory tasks.

Part-list cuing as instructed retrieval inhibition

The reexposure of a subset of learned material as a retrieval cue can impair recall of the remaining material. Like part-list relearning--the reexposure of learned material for additional learning--this part-list cuing is often assumed to be the result of output order biases at test, caused by the increased strength of the reexposed material. We directly compared the effects of cuing and relearning when controlling for output order biases. In addition, we compared the two forms of reexposure with the effect of part-list retrieval. Both part-list cuing and part-list retrieval reduced recall performance for the remaining material. By contrast, part-list relearning had no such detrimental effect. These results indicate that the effect of reexposure depends on whether material is reexposed as a cue or for relearning, suggesting that part-list cuing reflects an instructional effect. Evidence is provided that part-list cuing leads to instructed covert retrieval of cue items and causes retrieval inhibition of noncue items, similar to how overt retrieval inhibits nonretrieved items.

Effects of auditory and visual stimuli on motor facilitation of speech muscles

Transcranial magnetic stimulation (TMS) was applied to the left motor cortex during presentation of video and audio speech stimuli. Motor evoked potentials (MEPs) were recorded from the right orbicularis oris muscle which is activated during pronunciation of the consonant /ba/ but not the consonant /ta/. Subjects were instructed to pay attention to six types of stimuli video presentation of the consonant /ba/, audio presentation of /ba/, audio and video presentation of /ba/, video presentation of /ta/, audio presentation of /ba/ with time-locked video presentation of video /ta/, and the face of the speaker when he was silent. The MEPs were enhanced only when subjects were visually presented with the consonant /ba/. Auditory presentations of the same consonant failed to elicit similar enhancement. The results from visual observation of the consonant /ba/ support other studies of motor facilitation in limb control research in monkeys and humans. In these studies observation of a motor action present in the repertoire of the animal results in enhanced MEPs representing automatic, covert retrieval of the matching action in the premotor cortex. This retrieval is, however, modality dependent. Auditorily presented signals do not trigger action retrieval from the premotor cortex in an identical way.