Reduction of the self-reference effect in younger and older adults

Relating information to the self improves memory. However, this self-reference effect (SRE) is typically studied through explicit self-judgments on individual trials. The current study assessed whether a self-referential mode of thought, induced through a writing task, also induced an SRE on a later task. The study also tested the effects of aging on the SRE, given that a long-lasting mnemonic strategy may be especially relevant for this group. Ninety-two younger adults and 60 older adults were assigned to different writing conditions and then completed an unrelated SRE task. Across younger and older adults, the classic SRE effect was observed in the narrative writing condition, reduced in the semantic self-reference condition, and further reduced in the episodic self-reference condition. These results support the induction of a self-referential mode of thought, but this mode does not enhance memory. The classic SRE effect can be reduced after thinking about the self by reflecting on autobiographical memories. Results argue for a single shared self-referential mechanism that can be accessed through self-focused writing or the classic SRE task

STOP SHOUTING AT ME: The Influence of Case and Self-Referencing on Explicit and Implicit Memory

Evidence suggests that physical changes in word appearance, such as those written in all capital letters, and the use of effective encoding strategies, such as self-referential processing, improves memory. In this study we examined the extent both physical changes in word appearance (case) and encoding strategies engaged at study influence memory as measured by both explicit and implicit memory measures. Participants studied words written in upper and lower case under three encoding conditions (self-reference, semantic control, case judgment), which was followed by an implicit (word stem completion) and then an explicit (item and context) memory test. There were two primary results. First, analyses indicated a case enhancement effect for item memory where words written in upper case were better remembered than lower case, but only when participants were prompted to attend to the case of the word. Importantly, this case enhancement effect came at a cost to context memory for words written in upper case. Second, self-referencing increased explicit memory performance relative to control, but there was no effect on implicit memory. Overall, results suggest an item-context memory trade-off for words written in upper case, highlighting a potential downside to writing in all capital letters, and further, that both physical changes to the appearance of words and differing encoding strategies have a strong influence on explicit, but not implicit memory

Task-Selective Memory Effects for Successfully Implemented Encoding Strategies

Previous behavioral evidence suggests that instructed strategy use benefits associative memory formation in paired associate tasks. Two such effective encoding strategies–visual imagery and sentence generation–facilitate memory through the production of different types of mediators (e.g., mental images and sentences). Neuroimaging evidence suggests that regions of the brain support memory reflecting the mental operations engaged at the time of study. That work, however, has not taken into account self-reported encoding task success (i.e., whether participants successfully generated a mediator). It is unknown, therefore, whether task-selective memory effects specific to each strategy might be found when encoding strategies are successfully implemented. In this experiment, participants studied pairs of abstract nouns under either visual imagery or sentence generation encoding instructions. At the time of study, participants reported their success at generating a mediator. Outside of the scanner, participants further reported the quality of the generated mediator (e.g., images, sentences) for each word pair. We observed task-selective memory effects for visual imagery in the left middle occipital gyrus, the left precuneus, and the lingual gyrus. No such task-selective effects were observed for sentence generation. Intriguingly, activity at the time of study in the left precuneus was modulated by the self-reported quality (vividness) of the generated mental images with greater activity for trials given higher ratings of quality. These data suggest that regions of the brain support memory in accord with the encoding operations engaged at the time of study

The self-reference effect in dementia: Differential involvement of cortical midline structures in Alzheimer’s disease and behavioural-variant frontotemporal dementia

Encoding information in reference to the self enhances subsequent memory for the source of this information. In healthy adults, self-referential processing has been proposed to be mediated by the cortical midline structures (CMS), with functional differentiation between anterior-ventral, anterior-dorsal and posterior regions. While both Alzheimer’s disease (AD) and behavioural-variant frontotemporal dementia (bvFTD) patients show source memory impairment, it remains unclear whether they show a typical memory advantage for self-referenced materials. We also sought to identify the neural correlates of this so-called ‘self-reference effect’ (SRE) in these patient groups. The SRE paradigm was tested in AD (n=16) and bvFTD (n=22) patients and age-matched healthy controls (n=17). In this task, participants studied pictures of common objects paired with one of two background scenes (sources) under self-reference or other-reference encoding instructions, followed by an item and source recognition memory test. Voxel-based morphometry was used to investigate correlations between SRE measures and regions of grey matter atrophy in the CMS. The behavioural results indicated that self-referential encoding did not ameliorate the significant source memory impairments in AD and bvFTD patients. Furthermore, the reduced benefit of self-referential relative to other-referential encoding was not related to general episodic memory deficits. Our imaging findings revealed that reductions in the SRE were associated with atrophy in the anterior-dorsal CMS across both patient groups, with additional involvement of the posterior CMS in AD and anterior-ventral CMS in bvFTD. These findings suggest that although the SRE is comparably reduced in AD and bvFTD, this arises due to impairments in different subcomponents of self-referential processing

Fewer Constraints Enhance the Generation Effect for Source Memory in Younger, but not Older Adults

The generation effect is the memory benefit for information that is self-generated compared to read. This effect is robust for both younger and older adults. Recent work with younger adults has shown that the generation effect for context memory (i.e., contextual details associated with an episode) can be increased when there are fewer rather than greater experimental constraints placed on what participants can generate. This increase in context memory is attributable to enhanced relational processing. Given older adults’ deficits in context memory the present study tested whether fewer generation constraints would similarly improve the generation effect for contextual details in older adults. In this study, we examined age differences in item and context (i.e., source and associative) memory across three different tasks comprising the encoding of cue-target pairs: a lower-constraint generation task (i.e., free response to cue, such as assist – ____), a higher-constraint generation task (i.e., solving an anagram, such as assist – hlpe), and a read task (i.e., simply reading the cue-target pair, such as assist – help). Both age groups showed improved item and context memory for materials studied during the generation tasks (both lower- and higher-constraint) compared to the read task. However, only younger adults showed increased source memory for lower-constraint compared to higher-constraint generation, whereas older adults showed equivalent source and associative memory for both lower- and higher-constraint generation tasks. These findings suggest both age groups benefit from self-generation, but older adults may benefit less from conditions that enhance relational processing (lower-constraint generation) in younger adults

The Generation Effect Revisited: Fewer Generation Constraints Enhances Item and Context Memory

Self-generated information is often better remembered than non-self-generated information. This effect has been robust for item memory (i.e., the content of information) across many different experiments, but inconsistent for context memory (e.g., memory for the extraneous details of information, such as source). Previous studies examining the generation effect, however, have often applied constraints on the generation task possibly limiting the memory benefit from self-generation. In three experiments, we compared item and context memory for a lower-constraint generation task (i.e., free response to a cue word) relative to higher-constraint generation tasks (Exp. 1 & 2: scramble; Exp. 3: word fragment). Results showed that participants had better item and context memory in the lower-constraint compared to higher-constraint generation tasks. Overall, these experiments suggest that that the mnemonic benefits of self-generation depend on the level of task constraint. This study further advances the idea that self-generation is a powerful mnemonic that leads to enriched memory representations for both the item and context, especially when fewer generation constraints are imposed

Fewer Constraints Enhance the Generation Effect for Source Memory in Younger, but not Older Adults

The generation effect is the memory benefit for information that is self-generated compared to read. This effect is robust for both younger and older adults. Recent work with younger adults has shown that the generation effect for context memory (i.e., contextual details associated with an episode) can be increased when there are fewer rather than greater experimental constraints placed on what participants can generate. This increase in context memory is attributable to enhanced relational processing. Given older adults’ deficits in context memory the present study tested whether fewer generation constraints would similarly improve the generation effect for contextual details in older adults. In this study, we examined age differences in item and context (i.e., source and associative) memory across three different tasks comprising the encoding of cue-target pairs: a lower-constraint generation task (i.e., free response to cue, such as assist – ____), a higher-constraint generation task (i.e., solving an anagram, such as assist – hlpe), and a read task (i.e., simply reading the cue-target pair, such as assist – help). Both age groups showed improved item and context memory for materials studied during the generation tasks (both lower- and higher-constraint) compared to the read task. However, only younger adults showed increased source memory for lower-constraint compared to higher-constraint generation, whereas older adults showed equivalent source and associative memory for both lower- and higher-constraint generation tasks. These findings suggest both age groups benefit from self-generation, but older adults may benefit less from conditions that enhance relational processing (lower-constraint generation) in younger adults

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

Hit rates regardless of mediator success are displayed as a function of study condition in (A).

<p>Test phase response times for hit and error rates regardless of mediator success are displayed as a function of study condition in (B). The probabilities of hits conditionalized on the success of generating a mediator at encoding are displayed as a function of study condition in (C).</p

Regions showing the task main effect at the time of study for the visual imagery condition (A) and the sentence generation condition (B).

<p>Regions showing the task main effect at the time of study for the visual imagery condition (A) and the sentence generation condition (B).</p