Encoding strategy changes and spacing effects in the free recall of unmixed lists

Memory for repeated items often improves when repetitions are separated by other items—a phenomenon called the spacing effect. In two experiments, we explored the complex interaction between study strategies, serial position, and spacing effects. When people studied several unmixed lists, they initially used mainly rote rehearsal, but some people eventually adopted relational encoding strategies like creating a story from the items (Experiment 1). We observed overall spacing effects when participants used the story mnemonic, but not when they employed rote rehearsal strategies (Experiments 1 and 2). This occurred in part because the story mnemonic reduced or eliminated the usual recall advantage of immediately repeated items at the beginning of lists (Experiment 2)

Lasting reductions in illegal moves following increasing their cost: Evidence from river-crossing problems

Improving problem solving requires understanding what difficulties people have when they approach novel problems. Some of the known difficulties include identifying and understanding the operators (Kotovsky & Simon, 1990) or having implicit but wrong constraints on move selection (Richard, Poitrenaud, & Tijus, 1993), memory load imposed by the task or external circumstances (Kotovsky, Hayes, & Simon, 1985), whether the rules agree with real-world knowledge (Griggs & Cox, 1983; Kotovsky & Simon, 1990), difficulties in planning ahead (Atwood, Masson, & Polson, 1980; Atwood & Polson, 1976; Delaney, Ericsson, & Knowles, 2004), failures to sufficiently reflect on move selection (Davies, 2000), and heuristic biases that may lead problem solvers to select the wrong move at any given time (e.g., Atwood et al., 1980; Atwood & Polson, 1976)

The selective directed forgetting effect: Can people forget only part of a text?

Participants studied sentences describing two different characters and then were told to forget the sentences about only one of the characters. A second list contained sentences attributed to a third character. Subsequently, they received a recall test on the sentences about the original two characters. When the sentences could be thematically integrated, participants showed no directed forgetting relative to a control group that was never told to forget. However, with unrelated sentences, participants selectively forgot the target character's sentences without forgetting the other character's sentences. This selective directed forgetting effect is a novel empirical result. We interpret the results as consistent with Radvansky's (1999) ideas about inhibition with textual materials

Immediate and sustained effects of planning in problem solving

In 4 experiments, instructions to plan a task (water jugs) that normally produces little planning altered how participants solved the problems and resulted in enhanced learning and memory. Experiment 1 identified planning strategies that allowed participants to plan full solutions to water jugs problems. Experiment 2 showed that experience with planning led to better solutions even after planning was no longer required, whereas control participants showed little improvement. Experiments 3 and 4 showed that although the most recent planned solution could be recalled following a long filled retention interval, retroactive interference (RI) between successive problems resulted in much lower recall of earlier solutions. RI during plan generation could also explain participants’ choice of depth-first planning strategies

Uncovering the structure of a memorist's superior "basic" memory capacity

After extensive laboratory testing of the famous memorist Rajan, Thompson, Cowan, and Frieman (1993) proposed that he was innately endowed with a superior memory capacity for digits and letters and thus violated the hypothesis that exceptional memory fully reflects acquired ?skilled memory.? We successfully replicated the empirical phenomena that led them to their conclusions. From additional analyses and new experiments, we found support for an alternative hypothesis, namely that Rajan’s superior memory for digits was mediated by learned encoding techniques that he acquired during nearly a thousand hours of practice memorizing the mathematical constant p. Our paper describes a general experimental approach for studying the structure of exceptional memory and how Rajan’s unique structure is consistent with the general theoretical framework of long-term working memory (Ericsson & Kintsch, 1995)

Rote rehearsal and spacing effects in the free recall of pure and mixed lists

The spacing effect is the commonly observed phenomenon that memory for spaced repetitions is better than memory for massed repetitions. To further investigate the role of rehearsal in spacing effects, three experiments were conducted. With pure lists we found spacing effects in free recall when spacing intervals were relatively long (Experiments 1, 2 and 3), but not when spacing intervals were relatively short (Experiments 2 and 3). In contrast, with mixed lists spacing effects emerged at both short spacing intervals and long spacing intervals (Experiment 3). Additional analyses on the combined pure-list data revealed that the correlation between the primacy advantage and the spacing effect in Quadrants 2 through 4 was positive for all-massed lists and negative for all-spaced lists. This provides some first evidence for the zero-sum nature of the spacing effect in pure lists. The need to incorporate assumptions about rehearsal in theories of spacing is discussed

Rehearsal strategies can enlarge or diminish the spacing effect: Pure versus mixed lists and encoding strategy

Using 5 experiments, the authors explored the dependency of spacing effects on rehearsal patterns. Encouraging rehearsal borrowing produced opposing effects on mixed lists (containing both spaced and massed repetitions) and pure lists (containing only one or the other), magnifying spacing effects on mixed lists but diminishing spacing effects on pure lists. Rehearsing with borrowing produced large spacing effects on mixed lists but not on pure lists for both free recall (Experiment 1) and recognition (Experiment 2). In contrast, rehearsing only the currently visible item produced spacing effects on both mixed lists and pure lists in free recall (Experiment 3) and recognition (Experiment 4). Experiment 5 demonstrated these effects using a fully within-subjects design. Rehearse-aloud protocols showed that rehearsal borrowing redistributed study from massed to spaced items on mixed lists, especially during massed presentations

The strategy-specific nature of improvement: The power law applies by strategy within task

If strategy shifts speed up performance, learning curves should show discontinuities where such shifts occur. Relatively smooth curves appear consistently in the literature, however. To explore this incongruity, we examined learning when multiple strategies were used. We plotted power law learning curves for aggregated data from four mental arithmetic experiments and then plotted similar curves separately for each participant and strategy. We then evaluated the fits achieved by each group of curves. In all four experiments, plotting separately by strategy produced significantly better fits to individual participants’ data than did plotting a single power function. We conclude that improvement of solution time is better explained by practice on a strategy than by practice on a task, and that careful assessment of trial-by-trial changes in strategy can improve understanding of the effects of practice on learning

Reminders can enhance or impair episodic memory updating: a memory-for-change perspective

The Memory-for-Change framework proposes that retrieving episodic memories can facilitate new learning when changes between existing memories and new information are integrated during encoding and later recollected. Four experiments examined whether reminders could improve memory updating and enhance new learning. Participants studied two study lists of word pairs and were given a cued recall test on responses from both lists. Reminders of List 1 words pairs (A-B) appeared immediately before List 2 words pairs that included repeated cues and changed responses (A-D). Across experiments, we varied the types of reminders to determine whether differences in their effectiveness as retrieval cues would influence memory for the list membership of responses. We found that presenting intact reminders (cue-response) enhanced the memory benefits associated with recollection-based retrieval of changes relative to when no reminders appeared and when partial reminders (cue-only) appeared with and without feedback. Importantly, cue-response reminders benefitted memory when they were recognised in List 2 and when changes were later recollected. This suggests that integrative encoding can be facilitated when substantial environmental support is available to cue retrieval of existing memories. These findings have practical implications for understanding which reminders best aid the correction of memories for inaccurate information

Oh, Honey, I Already Forgot That : Strategic Control of Directed Forgetting in Older and Younger Adults*

This article is about age-related differences in intentional forgetting of unwanted information. Imagine receiving medication and reading the directions on how to take it. Afterwards, the doctor tells you to take a different dosage at a different time from that printed on the label. Updating the directions may necessitate intentional forgetting of the earlier-learned information. The current article took one approach to examining this issue by examining age differences in the effectiveness of intentional forgetting using the popular list-method directed forgetting procedure invented by R. A. Bjork, LaBerge, and LeGrand (1968)