Steven C. Pan

Sleep and Motor Learning: Is There Room for Consolidation?

It is widely believed that sleep is critical to the consolidation of learning and memory. In some skill domains, performance has been shown to improve by 20% or more following sleep, suggesting that sleep enhances learning. However, recent work suggests that those performance gains may be driven by several factors that are unrelated to sleep consolidation, inviting a reconsideration of sleeps theoretical role in the consolidation of procedural memories. Here we report the first comprehensive investigation of that possibility for the case of motor sequence learning. Quantitative meta-analyses involving 34 articles, 88 experimental groups and 1,296 subjects confirmed the empirical pattern of a large performance gain following sleep and a significantly smaller gain following wakefulness. However, the results also confirm strong moderating effects of 4 previously hypothesized variables: averaging in the calculation of prepost gain scores, build-up of reactive inhibition over training, time of testing, and training duration, along with 1 supplemental variable, elderly status. With those variables accounted for, there was no evidence that sleep enhances learning. Thus, the literature speaks against, rather than for, the enhancement hypothesis. Overall there was relatively better performance after sleep than after wakefulness, suggesting that sleep may stabilize memory. That effect, however, was not consistent across different experimental designs. We conclude that sleep does not enhance motor learning and that the role of sleep in the stabilization of memory cannot be conclusively determined based on the literature to date. We discuss challenges and opportunities for the field, make recommendations for improved experimental design, and suggest approaches to data analysis that eliminate confounds due to averaging over online learning. (PsycINFO Database Record

Does test-enhanced learning transfer for triple associates?

Test-enhanced learning and transfer for triple-associate word stimuli was assessed in three experiments. In each experiment, training and final-test trials involved the presentation of two words per triple associate (triplet), with the third word having to be retrieved. In agreement with the prior literature on different stimuli, training through testing with feedback yielded markedly better final-test performance than did restudy. However, in contrast to the positive transfer reported for paired associate stimuli, minimal or no positive transfer was observed, relative to a restudy control, from a trained cue combination (e.g., A, B, ?) to other cue combinations from the same triplet that required a different response (e.g., B, C, ?). That result also held when two unique cue combinations per triplet were tested during training, and for triplets with low and high average associative strengths. Supplementary analyses provided insight into the overall transfer effect: An incorrect response during training appears to yield positive transfer relative to restudy, whereas a correct response appears to yield no, or even negative, transfer. Cross-experiment analyses indicated that test-enhanced learning is not diminished when two or three cue combinations are presented during training. Thus, even though learning through testing is highly specific, testing on all possible stimulus–response combinations remains the most efficient strategy for the learning of triple associates.

Transfer of test-enhanced learning: Meta-analytic review and synthesis.

Attempting recall of information from memory, as occurs when taking a practice test, is one of the most potent training techniques known to learning science. However, does testing yield learning that transfers to different contexts? In the present article, we report the findings of the first comprehensive meta-analytic review into that question. Our review encompassed 192 transfer effect sizes extracted from 122 experiments and 67 published and unpublished articles (N = 10,382) that together comprise more than 40 years of research. A random-effects model revealed that testing can yield transferrable learning as measured relative to a nontesting reexposure control condition (d = 0.40, 95% CI [0.31, 0.50]). That transfer of learning is greatest across test formats, to application and inference questions, to problems involving medical diagnoses, and to mediator and related word cues; it is weakest to rearranged stimulus-response items, to untested materials seen during initial study, and to problems involving worked examples. Moderator analyses further indicated that response congruency and elaborated retrieval practice, as well as initial test performance, strongly influence the likelihood of positive transfer. In two assessments for publication bias using PET-PEESE and various selection methods, the moderator effect sizes were minimally affected. However, the intercept predictions were substantially reduced, often indicating no positive transfer when none of the aforementioned moderators are present. Overall, our results motivate a three-factor framework for transfer of test-enhanced learning and have practical implications for the effective use of practice testing in educational and other training contexts.

Time for considering the possibility that sleep plays no unique role in motor memory consolidation: Reply to Adi-Japha and Karni (2016).

The hypothesis that sleep makes a unique contribution to motor memory consolidation has been debated in recent years. In the target article (Pan & Rickard, 2015), we reported results of a comprehensive meta-analysis of the explicit motor sequence learning literature in which evidence was evaluated for both enhanced performance after sleep and stabilization after sleep. After accounting for confounding variables, we found no compelling evidence for either empirical phenomenon, and hence no compelling evidence for sleep-specific consolidation. In their comment, Adi-Japha and Karni (2016) critiqued the target article on three primary grounds: (a) our unrealistic (in their view) assumption that, if sleep-specific consolidation occurs, it is mechanistically unitary across all variants of the motor sequence experiments included in the meta-analysis, (b) our inclusion of child groups, which they believe may have resulted in an underestimation of sleep effects among adult groups, and (c) our inclusion of several experiments with atypical experimental designs, which may have introduced unaccounted for heterogeneity. In this reply we address each of those potentially legitimate concerns. We show that the metaregression allowed for tests of multiple candidate variables that could engender separate consolidation mechanisms, yielding no behavioral evidence for it. We also show through reanalysis that the inclusion of child groups had virtually no impact on the parameter estimates among adults, and that the inclusion of experiments with atypical designs did not materially influence parameter estimates. (PsycINFO Database Record

Does testing with feedback improve adult spelling skills relative to copying and reading

We examined testings ability to enhance adult spelling acquisition, relative to copying and reading. Across 3 experiments in which testing with feedback was compared with copying, the spelling improvement after testing matched that following the same amount of time spent copying. A potent testing advantage, however, was observed for spelling words free-recalled. In the fourth experiment, a large testing advantage for both word free recall and spelling was observed, versus reading. Subjects also generally preferred testing and rated it as more effective than copying or reading. The equivalent performance of testing and copying for spelling contrasts with prior work involving children and suggests that retrieval practice may not be the only effective mechanism for spelling skill acquisition. Rather, we suggest that the critical learning event for spelling is focused study on phoneme-to-grapheme mappings for previously unlearned letter sequences. For adults with extensive spelling expertise, focused study is more automatic during both copying and testing with feedback than for individuals with beginning spelling skills. Reading, however, would not be expected to produce efficient focused study of phoneme-to-grapheme mappings, regardless of expertise level. Overall, adult spelling skill acquisition benefits both from testing and copying, and substantially less from reading.

A dual memory theory of the testing effect

A new theoretical framework for the testing effect—the finding that retrieval practice is usually more effective for learning than are other strategies—is proposed, the empirically supported tenet of which is that separate memories form as a consequence of study and test events. A simplest case quantitative model is derived from that framework for the case of cued recall. With no free parameters, that model predicts both proportion correct in the test condition and the magnitude of the testing effect across 10 experiments conducted in our laboratory, experiments that varied with respect to material type, retention interval, and performance in the restudy condition. The model also provides the first quantitative accounts of (a) the testing effect as a function of performance in the restudy condition, (b) the upper bound magnitude of the testing effect, (c) the effect of correct answer feedback, (d) the testing effect as a function of retention interval for the cases of feedback and no feedback, and (e) the effect of prior learning method on subsequent learning through testing. Candidate accounts of several other core phenomena in the literature, including test-potentiated learning, recognition versus cued recall training effects, cued versus free recall final test effects, and other select transfer effects, are also proposed. Future prospects and relations to other theories are discussed.

Does retrieval practice enhance learning and transfer relative to restudy for term-definition facts?

In many pedagogical contexts, term-definition facts that link a concept term (e.g., “vision”) with its corresponding definition (e.g., “the ability to see”) are learned. Does retrieval practice involving retrieval of the term (given the definition) or the definition (given the term) enhance subsequent recall, relative to restudy of the entire fact? Moreover, does any benefit of retrieval practice for the term transfer to later recall of the definition, or vice versa? We addressed those questions in 4 experiments. In each, subjects first studied term-definition facts and then trained on two thirds of the facts using multiple-choice tests with feedback. Half of the test questions involved recalling terms; the other half involved recalling definitions. The remaining facts were either not trained (Experiment 1) or restudied (Experiments 2–4). A 48-hr delayed multiple-choice (Experiments 1–2) or short answer (Experiments 3a–4) final test assessed recall of all terms or all definitions. Replicating and extending prior research, retrieval practice yielded improved recall and positive transfer relative to no training. Relative to restudy, however, retrieval practice consistently enhanced subsequent term retrieval, enhanced subsequent definition retrieval only after repeated practice, and consistently yielded at best minimal positive transfer in either direction. Theoretical and practical implications are discussed.