Neural representation of a one-week delay in remembering information after production and self-generated elaboration encoding strategy

Many studies have confirmed the memory enhancement effect of production, generation and elaboration which can be effective after only one encoding. It is also known that greater memory enhancement effects can be obtained by combining multiple memory strategies during encoding. This study aimed to investigate whether the combination of production and self-generated elaboration enhances memory performance compared with production or generation alone. A total of 23 undergraduate and graduate students participated in this study. In the functional magnetic resonance imaging analysis, we explored the neural representation of remembering information after production and self-generated elaboration strategy. We set four encoding strategy conditions: (1) Read Silent (read without production), (2) Read Aloud (only production), (3) Add Silent (self-generated elaboration without production), (4) Add Aloud (production and self-generated elaboration). The retrieval performance and brain activity while retrieving the learned sentences after a one-week delay were examined. The behavioral results showed that the highest memory performance was for sentences encoded in Add Aloud. The interaction between production and self-generated elaboration was statistically significant. These results suggest that the memory enhancement effect of combining production and self-generated elaboration is not a simple addition nor synergistic facilitation effect. The imaging results showed that the following areas were related to the retrieval of the target encoded in the add aloud condition: the area related to integration of internal and external information (precuneus), area related to information rich stimuli (lateral occipital lobe), area related to self-involvement and inference of others' feelings (MPFC), area related to seen imagery (retrosplenial region) and area related to adjustment of movement (cerebellum). These results suggest that with an encoding strategy that combines production and self-generated elaboration, integrated auditory input of vocalizations and generated images, visual images of the scene, self-relevance, inference of other's feeling, movement by moving mouth are stored with the target and enhanced memory performance of AA.

Selecting effectively contributes to the mnemonic benefits of self-generated cues

Self-generated memory cues support recall of target information more robustly than memory cues generated by others. Across two experiments, we tested whether the benefit of self-generated cues in part reflects a meta-mnemonic effect rather than a pure generation effect. In other words, can learners select better memory cues for themselves than others can? Participants generated as many possible memory cues for each to-be-remembered target as they could and then selected the cue they thought would be most effective. Self-selected memory cues elicited better cued recall than cues the generator did not select and cues selected by observers. Critically, this effect cannot be attributed to the process of generating a cue itself because all of the cues were self-generated. Further analysis indicated that differences in cue selection arise because generators and observers valued different cue characteristics; specifically, observers valued the commonality of the cue more than the generators, while generators valued the distinctiveness of a cue more than observers. Together, results suggest that self-generated cues are effective at supporting memory, in part, because learners select cues that are tailored to their specific memory needs.

Theories of the generation effect and the impact of generation constraint: A meta-analytic review

The generation effect is the memory benefit for self-generated compared with read or experimenter-provided information. In recent decades, numerous theories have been proposed to explain the memory mechanism(s) and boundary conditions of the generation effect. In this meta-analysis and theoretical review, we analyzed 126 articles (310 experiments, 1,653 estimates) to assess 7 prominent theories to determine which theories are supported by the existing literature. Because some theories focus on item memory (memory for the generated target) and others focus on context memory (memory for details associated with the generated target), we examined memory effects for both types of details (item, context) in this meta-analysis. Further, we assessed the influence of generation constraint (how constrained participants are to generate a certain response), which recent work has shown affects the magnitude of the generation effect. Overall, the results of this meta-analysis support some theoretical accounts, but not others, as explanatory mechanisms of the generation effect. Results further showed that generation constraint significantly moderates the magnitude of the generation effect, suggesting that this factor should be rigorously investigated in future work. Overall, this meta-analysis provides a review and examination of generation effect theories, and reveals important areas of future research.

Examining the relationship between generation constraint and memory

Self-generated information is often better remembered than read information (the generation effect). Recent research, however, has shown that generating information under fewer experimental constraints (i.e., fewer limitations on what can be generated) can increase the magnitude of the generation effect. This study systematically varied generation constraint to better understand the effects of constraint on memory. Participants encoded associated cue-target word pairs (above-below) on either the left or right side of a computer monitor. At encoding, generation constraint was manipulated by systematically varying the number of letters given to participants to generate the target word (i.e., above-below; option-choic_; bank-mon__; etc.). At retrieval, participants were given either a recognition, cued recall, or free recall test measuring both item (target word) and context memory (location on the computer monitor). Using mixed-effects logistic regression analyses to control for item-selection effects (e.g., participants producing idiosyncratic targets in some conditions relative to others), results indicated that generation constraint significantly influenced item, but not context (location) memory. The relationship between generation constraint and memory performance, however, differed by the type of memory test administered: Recognition data revealed a curvilinear relationship; cued recall showed a negative, linear relationship; and free recall showed no significant relationship. Overall, these findings provide more evidence that generation constraint has a strong yet complex effect on different aspects of memory, and further delineates some boundary conditions of the influence of generation constraint on memory.

Fewer generation constraints increase the generation effect for item and source memory through enhanced relational processing

Memory is often better for information that is self-generated versus read (i.e. the generation effect). Theoretical work attributes the generation effect to two mechanisms: enhanced item-specific and relational processing (i.e. the two-factor theory). Recent work has demonstrated that the generation effect increases when generation tasks place lower, relative to higher, constraints on what participants can self-generate. This study examined whether the effects of generation constraint on memory might be attributable to either mechanism of the two-factor theory. Across three experiments, participants encoded word pairs in two generation conditions (lower- and higher-constraint) and a read control task, followed by a memory test for item memory and two context memory details (source and font color). The results of these experiments support the idea that lower-constraint generation increases the generation effect via enhanced relational processing, as measured through both recognition and cued recall tasks. Results further showed that lower-constraint generation improves context memory for conceptual context (source), but not perceptual context (color), suggesting that this enhanced relational processing may extend to conceptually related details of an item. Overall, these results provide more evidence that fewer generation constraints increase the generation effect and implicate enhanced relational processing as a mechanism for this improvement.

Slow naming of pictures facilitates memory for their names

Speakers remember their own utterances better than those of their interlocutors, suggesting that language production is beneficial to memory. This may be partly explained by a generation effect: The act of generating a word is known to lead to a memory advantage (Slamecka & Graf, 1978). In earlier work, we showed a generation effect for recognition of images (Zormpa, Brehm, Hoedemaker, & Meyer, 2019). Here, we tested whether the recognition of their names would also benefit from name generation. Testing whether picture naming improves memory for words was our primary aim, as it serves to clarify whether the representations affected by generation are visual or conceptual/lexical. A secondary aim was to assess the influence of processing time on memory. Fifty-one participants named pictures in three conditions: after hearing the picture name (identity condition), backward speech, or an unrelated word. A day later, recognition memory was tested in a yes/no task. Memory in the backward speech and unrelated conditions, which required generation, was superior to memory in the identity condition, which did not require generation. The time taken by participants for naming was a good predictor of memory, such that words that took longer to be retrieved were remembered better. Importantly, that was the case only when generation was required: In the no-generation (identity) condition, processing time was not related to recognition memory performance. This work has shown that generation affects conceptual/lexical representations, making an important contribution to the understanding of the relationship between memory and language.

Optimizing memory strategy use in young and older adults: The role of metamemory and internal strategy use

We explored whether experiencing differential efficacy of reading and generation for memory in an initial learning trial led younger and older adults to improve recall of read items in a subsequent learning trial, leading to a reduction of the generation effect. In the first trial, generation improved the memory performance of both young and older adults. However, in Trial 2, the generation effect remained significant for older adults only, confirming that they did not change the way they processed read items, unlike the young adults. The older adults were also less spontaneously aware that generation led to better memory performance in the first trial, and, in contrast to the young adults, awareness did not result in a reduction of the generation effect. Moreover, the age-related differences in generation effect reduction were mediated by an independent measure of self-reported internal strategy use. However, when an appropriate environmental support was provided between both trials, older adults improved read items recall at the second trial as well as younger ones, leading to an elimination of the generation advantage for both groups. Environmental support reduced the implication of internal strategy use in the generation effect reduction, suggesting that age-related differences in the implementation of effective encoding processes in Trial 2 would be the consequence of a metamemory deficit, and reduced capacity to self-initiate internal strategies.

Comparison of opportunities to respond and generation effect as potential causal mechanisms for incremental rehearsal with multiplication combinations

Incremental rehearsal (IR) is an intervention with demonstrated effectiveness in increasing retention of information, yet little is known about how specific intervention components contribute to the intervention's effectiveness. The purpose of this study was to further the theoretical understanding of the intervention by comparing the effects of opportunities to respond (OTR) and generation demand on retention of multiplication combinations. Using a between subject 2 × 2 factorial design, 103 4th and 5th grade students were taught seven multiplication combinations using one of four versions of IR that orthogonally varied OTR (high versus low) and generation demands (high versus low). A two-way ANOVA revealed main effects for OTR, generation demands, and an interaction of the two factors. The effect of generation demands was large (d=1.31), whereas the overall effect of OTR was moderate (d=0.66). Critically, the two factors interacted, with the largest learning gains observed when OTR and generation demands were both high. The results of this study suggest that generation demand is an important factor in the effectiveness of rehearsal interventions.