Going beyond the spacing effect: Does it matter how time on a task is distributed?

We assessed the effects of removing some constraints that characterise traditional experiments on the effects of spaced, rather than massed, study opportunities. In five experiments-using lists of to-be-remembered words-we examined the effects of how total study time was distributed across multiple repetitions of a given to-be-remembered word. Overall, within a given list, recall profited from study time being distributed (e.g., four 1-s presentations or two 2-s presentations vs one 4-s presentation). Among the implications of these findings is that if students choose to engage in massed studying (by virtue of constraints on their study time or a failure to appreciate the benefits of spaced study sessions), then studying the information twice but for half the time may produce memory benefits in a single study session.

Forgetting as the friend of learning: implications for teaching and self-regulated learning.

One of the "important peculiarities" of human learning (Bjork RA and Bjork EL. From Learning Processes to Cognitive Processes: Essays in Honor of William K. Estes, 1992, p. 35-67) is that certain conditions that produce forgetting-that is, impair access to some to-be-learned information studied earlier-also enhance the learning of that information when it is restudied. Such conditions include changing the environmental context from when some to-be-learned material is studied to when that material is restudied; increasing the delay from when something is studied to when it is tested or restudied; and interleaving, rather than blocking, the study or practice of the components of to-be-learned knowledge or skills. In this paper, we provide some conjectures as to why conditions that produce forgetting can also enable learning, and why a misunderstanding of this peculiarity of how humans learn can result in nonoptimal teaching and self-regulated learning.

Improving encoding strategies as a function of test knowledge and experience.

Information that is produced or generated during learning is better remembered than information that is passively read, a phenomenon known as the generation effect. Prior research by deWinstanley and Bjork (Memory & Cognition, 32, 945-955, 2004) has shown that learners, after experiencing the memorial benefits of generation in the context of a fill-in-the-blank test following the study of a text passage containing both to-be-read and to-be-generated items, become more effective encoders of to-be-read items on a second passage, thus eliminating the generation effect on a subsequent memory test. Current explanations of this phenomenon assume that learners need to actually experience the generation advantage on the test of the first passage to become more effective encoders of to-be-read items on the second passage. The results of the present research, however, suggest otherwise. Although experiencing a test of the first passage does appear to be critical for leading participants to become better encoders on the second passage, experiencing a generation advantage on the test for the first passage is not. More generally, these results shine new light on the generation effect as well as how and why taking tests has the potential to improve subsequent learning.

Using verification feedback to correct errors made on a multiple-choice test.

A key educational challenge is how to correct students' errors and misconceptions so that they do not persist. Simply labelling an answer as correct or incorrect on a short-answer test (verification feedback) does not improve performance on later tests; error correction requires receiving answer feedback. We explored the generality of this conclusion and whether the effectiveness of verification feedback depends on the type of test with which it is paired. We argue that, unlike for short-answer tests, learning whether one's multiple-choice selection is correct or incorrect should help participants narrow down the possible answers and identify specific lures as false. To test this proposition we asked participants to answer a series of general knowledge multiple-choice questions. They received no feedback, answer feedback, or verification feedback, and then took a short-answer test immediately and two days later. Verification feedback was just as effective as answer feedback for maintaining correct answers. Importantly, verification feedback allowed learners to correct more of their errors than did no feedback, although it was not as effective as answer feedback. Overall, verification feedback conveyed information to the learner, which has both practical and theoretical implications.

Part-list cuing and the dynamics of false recall.

False recall of an unpresented critical word after studying its semantic associates can be reduced substantially if the strongest and earliest-studied associates are presented as part-list cues during testing (Kimball & Bjork, 2002). To disentangle episodic and semantic contributions to this decline in false recall, we factorially manipulated the cues' serial position and their strength of association to the critical word. Presenting cues comprising words that had been studied early in a list produced a greater reduction in false recall than did presenting words studied late in the list, independent of the cues' associative strength, but only when recall of the cues themselves was prohibited. When recall of the cues was permitted, neither early-studied nor late-studied cues decreased false recall reliably, relative to uncued lists. The findings suggest that critical words and early-studied words share a similar fate during recall, owing to selective episodic strengthening of their associations during study.

Knowledge retention after an online tutorial: a randomized educational experiment among resident physicians.

BACKGROUND: The time course of physicians' knowledge retention after learning activities has not been well characterized. Understanding the time course of retention is critical to optimizing the reinforcement of knowledge. DESIGN: Educational follow-up experiment with knowledge retention measured at 1 of 6 randomly assigned time intervals (0-55 days) after an online tutorial covering 2 American Diabetes Association guidelines. PARTICIPANTS: Internal and family medicine residents. MEASUREMENTS: Multiple-choice knowledge tests, subject characteristics including critical appraisal skills, and learner satisfaction. RESULTS: Of 197 residents invited, 91 (46%) completed the tutorial and were randomized; of these, 87 (96%) provided complete follow-up data. Ninety-two percent of the subjects rated the tutorial as "very good" or "excellent." Mean knowledge scores increased from 50% before the tutorial to 76% among those tested immediately afterward. Score gains were only half as great at 3-8 days and no significant retention was measurable at 55 days. The shape of the retention curve corresponded with a 1/4-power transformation of the delay interval. In multivariate analyses, critical appraisal skills and participant age were associated with greater initial learning, but no participant characteristic significantly modified the rate of decline in retention. CONCLUSIONS: Education that appears successful from immediate posttests and learner evaluations can result in knowledge that is mostly lost to recall over the ensuing days and weeks. To achieve longer-term retention, physicians should review or otherwise reinforce new learning after as little as 1 week.

The memorial consequences of multiple-choice testing.

The present article addresses whether multiple-choice tests may change knowledge even as they attempt to measure it. Overall, taking a multiple-choice test boosts performance on later tests, as compared with non-tested control conditions. This benefit is not limited to simple definitional questions, but holds true for SAT II questions and for items designed to tap concepts at a higher level in Bloom's (1956) taxonomy of educational objectives. Students, however, can also learn false facts from multiple-choice tests; testing leads to persistence of some multiple-choice lures on later general knowledge tests. Such persistence appears due to faulty reasoning rather than to an increase in the familiarity of lures. Even though students may learn false facts from multiple-choice tests, the positive effects of testing outweigh this cost.

When intended remembering leads to unintended forgetting.

As a means of clarifying the memory dynamics that underlie retrieval-induced forgetting, we explored how instructing participants either to remember or to forget a previously presented list of items influences the susceptibility of those items to inhibition. According to the inhibitory account of retrieval-induced forgetting, it is the items that interfere most with retrieval practice that should be the most susceptible to the effects of inhibition. Consistent with this prediction, items from lists that participants were told to remember suffered from significantly more retrieval-induced forgetting than did items from lists that participants were told to forget.

Is retrieval success a necessary condition for retrieval-induced forgetting?

When information is retrieved from memory, it becomes more recallable than it would have been otherwise. Other information associated with the same cue or configuration of cues, however, becomes less recallable. Such retrieval-induced forgetting (Anderson, Bjork, & Bjork, 1994) appears to reflect the suppression of competing nontarget information, with this suppression facilitating the selection of target information. But is success at such selection a necessary condition for retrieval-induced forgetting? Using a procedure in which some cues posed an impossible retrieval task for participants, we report evidence that the attempt to retrieve, even if unsuccessful, can produce retrieval-induced forgetting. This finding, we believe, supports and refines a suppression/inhibitory account of retrieval-induced forgetting.