Deconstructing episodic memory with construction

It has recently been observed that the brain network supporting recall of episodic memories shares much in common with other cognitive functions such as episodic future thinking, navigation and theory of mind. It has been speculated that 'self-projection' is the key common process. However, in this Opinion article, we note that other functions (e.g. imagining fictitious experiences) not explicitly connected to either the self or a subjective sense of time, activate a similar brain network. Hence, we argue that the process of 'scene construction' is better able to account for the commonalities in the brain areas engaged by an extended range of disparate functions. In light of this, we re-evaluate our understanding of episodic memory, the processes underpinning it and other related cognitive functions.     

生理周期对情景记忆的影响

来自进化心理学的理论及研究结果提示, 女性性激素可能是情景记忆的重要影响因素, 但是, 具体机制尚不清晰。本研究以女性生理周期性激素水平的自然变化构成的两个时期(卵泡后期、黄体中期)为自变量, 利用“What-Where-When Task”情景记忆任务(实验1), 结合事件相关电位(event-related potential, ERP)技术(实验2), 探讨生理周期不同阶段完成情景记忆任务的成绩及其可能的内在机制。实验1招募生理周期稳定的33名女性为被试, 在卵泡后期和黄体中期各参加一次实验, 随机顺序依次完成O任务(仅记忆物品, object)、P任务(仅记忆物品位置, position)、OO任务(记忆物品及其呈现顺序, object + order)、OP任务(记忆物品及其呈现位置, object + position)以及PO任务(记忆物品呈现位置及顺序, position + order)。结果发现, 在完成PO任务时, 黄体中期的回忆正确率显著高于卵泡后期。实验2借用事件相关电位技术, 进一步探究生理周期影响情景记忆PO任务的原因, 结果发现, 黄体中期额叶脑区的P300以及LPC波的振幅显著大于卵泡后期, 且完成PO任务时的感受性与右侧额叶P300振幅显著正相关。基于上述ERP的结果, 可以认为, 黄体中期在PO任务上的好成绩可能得益于显著增强的认知控制能力, 这一解释符合前人研究结论。总之, 本研究发现：生理周期对情景记忆中客体的空间位置与时间顺序整合的记忆产生显著影响, 黄体中期的记忆效果显著好于卵泡后期, 可能是因为该时期显著增强的认知控制能力。本研究有望为理解影响情景记忆的因素提供新的视角。     

Word imageability influences the emotionality effect in episodic memory

Cognitive Processing - This study examines how and to what extent imageability influences the effect of word emotionality in episodic memory. A total of 52 young adults successively performed a...     

老年人情景记忆更新的改变：竞争记忆的回溯性干扰

记忆更新是获取新知识的一种重要能力。大量研究显示老年人情景记忆受损,但鲜有研究探讨老年人情景记忆更新模式的改变。研究在匹配了老年人和年轻人编码程度的前提下,探讨情景记忆更新的老化效应及其潜在的认知机制。我们对AB-AC记忆更新范式进行了创新,同时考察了在项目改变和位置改变条件下的老化效应,并在测试阶段纳入诱饵选项,进一步排除编码程度带来的影响。研究结果显示年轻人能对A-B和A-C记忆分离存储,而老年人更多地受到回溯性记忆干扰,即在A-B测试中出现C的闯入,并且该干扰效应显著地大于诱饵刺激带来的影响。研究结果表明,在年轻人和老年人编码程度匹配的情况下,年轻人的记忆更新通过记忆分化来实现,而老年人更多地受到竞争记忆的回溯性干扰。     

The temporal contiguity effect predicts episodic memory performance

One way to study the associative processes at work during episodic memory is to examine the order of participant responses, which reveal the strong tendency to transition between temporally contiguous or semantically proximal items on the study list. Here, we assessed the correlation between participants’ recall performance and their use of semantic and temporal associations to guide retrieval across nine delayed free recall studies. The size of the participants’ temporal contiguity effects predicted their recall performance. When interpreted in terms of two models of episodic memory, these results suggest that participants who more effectively form and retrieve associations between items that occur nearby in time perform better on episodic recall tasks. Sample code may be downloaded as a supplement for this article from http://mc.psychonomic-journals.org/content/ supplemental.     

The effect of childhood bilingualism on episodic and semantic memory tasks

Kormi-Nouri, Moniri and Nilsson (2003) demonstrated that Swedish-Persian bilingual children recalled at a higher level than Swedish monolingual children, when they were tested using Swedish materials. The present study was designed to examine the bilingual advantage of children who use different languages in their everyday life but have the same cultural background and live in their communities in the same way as monolingual children. In four experiments, 488 monolingual and bilingual children were compared with regard to episodic and semantic memory tasks. In experiments 1 and 2 there were 144 boys and 144 girls in three school groups (aged 9-10 years, 13-14 years and 16-17 years) and in three language groups (Persian monolingual, Turkish-Persian bilingual, and Kurdish-Persian bilingual). In experiments 3 and 4, there were 200 male students in two school groups (aged 9-10 years and 16-17 years) and in two language groups (Persian monolingual and Turkish-Persian bilingual). In the episodic memory task, children learned sentences (experiments 1-3) and words (Experiment 4). Letter and category fluency tests were used as measures of semantic memory. To change cognitive demands in memory tasks, in Experiment 1, the integration of nouns and verbs within sentences was manipulated by the level of association between verb and noun in each sentence. At retrieval, a recognition test was used. In experiments 2 and 3, the organization between sentences was manipulated at encoding in Experiment 2 and at both encoding and retrieval in Experiment 3 through the use of categories among the objects. At retrieval, free recall or cued recall tests were employed. In Experiment 4, the bilingual children were tested with regard to both their first and their second language. In all four experiments, a positive effect of bilingualism was found on episodic and semantic memory tasks; the effect was more pronounced for older than younger children. The bilingual advantage was not affected by changing cognitive demands or by using first/second language in memory tasks. The present findings support the cross-language interactivity hypothesis of bilingual advantage.     

Deconstructing the better-than-average effect

The tendency for people to evaluate themselves more favorably than an average-peer--the better-than-average effect (BTAE)--is among the most well-documented effects in the social-psychological literature. The BTAE has been demonstrated in many populations with various methodologies, and several explanations have been advanced for it. Two essential questions remain conspicuously unanswered in the BTAE literature. The first concerns the extent to which the BTAE can be represented as a social-comparative phenomenon, and the second concerns the role that strategic motivational processes play in self versus average-peer judgments. With regard to the first question, Study 1 provides direct experimental evidence that self versus average-peer judgments are made relationally rather than independently and, further, that self-ratings anchor these relational judgments. Moreover, Study 1 demonstrates that the consequence of this comparison is for judgments of average to be assimilated toward, not contrasted from, self-ratings. Studies 2-4 provide evidence that self-enhancement motives play a moderating role in the outcome of self versus average-peer judgments. We show that for dimensions on which the self is positively evaluated, enhancement motives restrict the extent to which average-peer assimilation occurs (Study 2). But for dimensions on which the self is negatively evaluated, enhancement motives amplify average-peer assimilation (Studies 3 and 4). Discussion focuses on the function of such differential assimilation, the relation of the current findings to extant perspectives, and directions for future research.     

The influence of action on episodic memory: A virtual reality study

A range of empirical findings suggest that active learning is important for memory. However, few studies have focused on the mechanisms underlying this enactment effect in episodic memory using complex environments. Research using virtual reality has yielded inconsistent results. We postulated that the effect of action depends on the degree of interaction with the environment and freedom in the planning of an itinerary. To test these hypotheses, we disentangled the interaction and planning components of action to investigate whether each enhances factual and spatial memory. Seventy-two participants (36 male and 36 female) explored a virtual town in one of three experimental conditions: (a) a passive condition where participants were immersed as passenger of the car (no interaction, no planning); (b) a planning-only condition (the subject chose the itinerary but did not drive the car); (c) an interaction-only condition (the subject drove the car but the itinerary was fixed). We found that itinerary choice and motor control both enhanced spatial memory, while factual memory was impaired by online motor control. The role of action in memory is discussed.     

A study on episodic memory reconsolidation that tells us more about consolidation

Awake quiescence immediately after encoding is conducive to episodic memory consolidation. Retrieval can render episodic memories labile again, but reconsolidation can modify and restrengthen them. It remained unknown whether awake quiescence after retrieval supports episodic memory reconsolidation. We sought to examine this question via an object-location memory paradigm. We failed to probe the effect of quiescence on reconsolidation, but we did observe an unforeseen “delayed” effect of quiescence on consolidation. Our findings reveal that the beneficial effect of quiescence on episodic memory consolidation is not restricted to immediately following encoding but can be achieved at a delayed stage and even following a period of task engagement.

For labile new memories to be remembered they must be consolidated, that is, strengthened and stabilized, over time (Dudai 2004; Wixted 2004). Extensive research demonstrates that postencoding sleep and awake quiescence (quiet rest) are conducive to human episodic memory consolidation (Clemens et al. 2005; Ferrara et al. 2008; Lahl et al. 2008; Wamsley et al. 2010; Dewar et al. 2012, 2014; Gaskell et al. 2014; Mercer 2015; Brokaw et al. 2016; Craig and Dewar 2018; Craig et al. 2019; Sacripante et al. 2019). Sleep and wakeful rest are hypothesized to support consolidation by providing a state of reduced sensory input and task engagement (Hasselmo 1999; Wixted 2004; Mednick et al. 2011; Dewar et al. 2012, 2014; Craig and Dewar 2018; Craig et al. 2019).Memories are not destined to remain fixed and unmodifiable once consolidated. An increasing body of evidence suggests that the cueing or retrieval of consolidated memories, for example, via internally or externally generated exposure to learned materials (Wichert et al. 2011; Agren 2014), can return such memories into a labile state (Dudai and Eisenberg 2004; McKenzie and Eichenbaum 2011; Schwabe et al. 2014). These relabilized memories are thought to require a process of “reconsolidation” (Rodriguez et al. 1993; Przybyslawski and Sara 1997) in order to restabilize and persist. Evidence for reconsolidation in humans comes from research demonstrating that memories can be disrupted and/or updated by the application of treatments shortly following their retrieval. This includes (1) the disruption and modification of episodic memories via the presentation of similar/related materials (Loftus 2005; Hupbach et al. 2007), (2) a reduction in the number of traumatic memory intrusions following postretrieval engagement in visuospatial tasks (Deeprose et al. 2012; James et al. 2015; Hagenaars et al. 2017), and (3) the extinction of fear memories and increased forgetting of emotional memories via the administration of pharmaceuticals and electrophysiological stimulation (Cahill et al. 1994; Debiec and Ledoux 2004; Kroes et al. 2014). In all cases, the effect of postretrieval treatment is seen only for memories that are retrieved (e.g., via a memory test or cue) prior to the treatment. Memories that were not retrieved (i.e., controls) were unaffected, indicating that the treatment hampered reconsolidation specifically.Episodic memory reconsolidation can also be enhanced. Of particular interest to our study is the finding that reconsolidation, like consolidation, benefits from sleep. If recently or remotely encoded episodic memories are reactivated before an extended period of sleep, the reactivated memories are protected against further forgetting (for reviews, see Stickgold and Walker 2007; Dudai 2012; Spiers and Bendor 2014). Moreover, even naps benefit reconsolidation. It has been shown that a short 40-min nap period facilitated the reconsolidation of remote memories, whereas recently encoded memories did not benefit at all (Klinzing et al. 2016). It is possible that, as is the case for consolidation, sleep is conducive to reconsolidation because it provides a state of reduced cognitive engagement and sensory input (Hasselmo 1999; Wixted 2004; Mednick et al. 2011; Dewar et al. 2012). If so, awake quiescence, which has this in common with sleep, should also be conducive to reconsolidation.In the study reported here, we examined whether a period of awake quiescence following retrieval protects episodic memories from further forgetting by facilitating their reconsolidation. To this end, we combined a computerized item-location memory test with a modified version of our established consolidation paradigm, which compares between-subject effects of postencoding rest versus task engagement on recently encoded memories (e.g., Dewar et al. 2012). Item-location memory tests have previously been sensitive to the effects of postretrieval (reconsolidation) manipulations, including sleep (e.g., Klinzing et al. 2016) hence, subtle differences in memory scores can be recorded. Figure 1 provides an overview of the procedure. Sixty young adults (mean age = 21.47 yr, SD = 1.79 yr; 26M:34F) were sequentially presented photos of 60 everyday items in unique locations on a 22-in touchscreen computer monitor. Immediately after each object''s presentation, participants were asked to recall the object''s location via a touchscreen response as part of a “short-term spatial memory test” (encoding). They were unaware that they would perform subsequent long-term memory tests pertaining to the locations of these items. Location memory for half (N = 30) of the encoded items (“retrieved items”) was probed in a first delayed recall test that occurred after a 10-min delay filled with a visual spot-the-difference game (Dewar et al. 2012). There was no overlap between encoded items and spot-the-difference game stimuli. The first delayed recall test was followed by one of two postretrieval 10-min delay periods: (1) awake quiescence (quiet resting under strict conditions of minimal sensory input in a dimly lit room; N = 30 participants), or (2) a further filler task (a spot-the-difference game comprising different stimuli to earlier; N = 30 participants) (Dewar et al. 2012). Memory for the location of all 60 encoded items was then probed via a second delayed recall test. This test included the 30 items that were probed during the first delayed recall test (retrieved items) and the 30 control items that were not probed during the first delayed recall test (nonretrieved items). Our key measure was the distance of error (in centimeters) between the initially presented locations of the everyday objects during encoding, and the recalled location during the first and second delayed recall tests. We also recorded the time that participants took to respond as well as confidence ratings during encoding and the first and second delayed recall tests. Analyzes were performed using SPSS 19 using ANOVAs, RM ANOVAs. and follow up t-tests that were used to investigate possible between-group differences. See the Supplemental Materials for detailed methods.Open in a separate windowFigure 1.Experimental paradigm. Participants were presented 60 photos of unique everyday items from the Mnemonic Similarity Task (e.g., Stark et al. 2013) in unique locations on a computer screen. They then experienced 10 min of a postencoding delay task (a spot-the-difference game). Memory for the location of half of the encoded items (N = 30) was then probed via a first delayed recall test (via touchscreen response), before participants completed one of two postretrieval delay periods, each of which was 10 min in duration: awake quiescence (N = 30) (A), or an engaging perceptual task (a further spot-the-difference game comprising different stimuli to the earlier one) (N = 30) (B). In the subsequent second delayed recall test, participants’ memory for the location of all the retrieved and nonretrieved items was probed (N = 60) (via touchscreen response). The experimental procedure took place in a single session.Given that our manipulation occurred during the postretrieval delay, we expected groups to be matched in their encoding, postencoding delay task, and first delayed memory test. Crucially, if postretrieval awake quiescence is conducive to episodic memory reconsolidation, then those who experience awake quiescence after the first delayed recall test should demonstrate less forgetting of “retrieved” items (smaller distances of error scores) in the second delayed recall test relative to those who experience the filler task after the first delayed recall test. Given that “control” items were not retrieved during the first delayed recall test immediately prior to our experimental manipulation (postretrieval quiescence vs. task), we predicted that memory (distance of error scores) for control items should be matched between groups in the second delayed recall test.Data from two participants (perceptual task group) were lost due to technical issues. Thus, the following analyzes report data from 58 participants (quiescence group: N = 30, perceptual task group: N = 28). The two groups were well matched in their backgrounds and performance of the postencoding delay task (spot-the-difference game) (see the Supplemental Material). Moreover, as expected, the two groups were well matched in all memory measures occurring prior to our experimental manipulation. Specifically, we found no significant main effect of group in the mean distance of error (in centimeters) during (1) encoding of the items (quiescence: mean = 1.84 cm, SD = 0.57; perceptual task: mean = 2.00 cm, SD = 0.47; F_(1,56) = 1.303, P = .259, η²_ρ = 0.023), (2) the first delayed recall test of the 30 “retrieved” items (quiescence: mean = 13.36 cm, SD = 3.37; perceptual task: mean = 14.17 cm, SD = 3.67; F_(1,56) = = 0.775, P = 0.383, η²_ρ = 0.014), or (3) the response times and confidence ratings in the first delayed recall test (see the Supplemental Material).The second delayed recall test was completed immediately following our experimental manipulation, where participants experienced 10 min of either (1) awake quiescence (N = 30 participants), or (2) ongoing sensory input and cognitive engagement via an unrelated perceptual task (a different spot-the-difference game; Dewar et al. 2012) (N = 30 participants). This delayed recall test included the 30 items that were probed during the first delayed recall test (retrieved items) and the 30 control items that were not probed during the first delayed recall test (nonretrieved items). A RM ANOVA comprised of within-subject factor item type (retrieved vs. nonretrieved) and between-subject factor group (awake quiescence vs. perceptual task) revealed no significant main effect of group in distance of error scores (in centimeters; F_(1,56) = 0.686, P = 0.411, η²_ρ = 0.012). We did, however, find a significant main effect of item type (retrieved vs. nonretrieved; F_(1,56) = 14.138, P < 0.001, η²_ρ = 0.202) because, overall, the distance of error (in centimeters) was larger for nonretrieved (mean = 14.56 cm, SD = 3.49 cm) than retrieved (mean = 13.36 cm, SD = 3.38 cm) items. There was a significant interaction between group (awake quiescence vs. perceptual task) and item type (retrieved vs. nonretrieved; F_(1,56) = 4.561, P = 0.037, η²_ρ = 0.075).Paired t-tests revealed that the above interaction emerged because, in the perceptual task group, the distance of error was significantly larger for nonretrieved (mean = 15.27, SD = 3.32 cm) than retrieved (mean = 13.37 cm, SD = 3.64 cm) items (t₍₂₇₎ = −5.05, P < 0.001; see Fig. 2). This significant finding survived Bonferroni correction for multiple comparisons (α level of 0.050/four comparisons = corrected α level of 0.013). This was not the case in the quiescence group, where no significant item type difference was observed (retrieved: mean = 13.36 cm, SD = 3.49 cm; nonretrieved: mean = 13.89 cm, SD = 3.26 cm; t₍₂₉₎ = −1.018, P = 0.317). Independent t-tests revealed no effect of delay group in the distance of error for retrieved items (quiescence: mean = 13.36 cm, SD = 3.49 cm; task: mean = 13.37, SD = 3.33; t₍₅₆₎ = −0.008, P = 0.994) or nonretrieved items (quiescence: mean = 13.88 cm, SD = 3.26 cm; task: mean = 15.27 cm, SD = 3.64 cm; t₍₅₆₎ = −1.530, P = 0.132). The groups were matched in their second delayed recall test response times and confidence ratings (see the Supplemental Material).Open in a separate windowFigure 2.Memory performance in the second delayed recall test. Mean distance of error (in centimeters) in the second delayed recall test for items that were and were not “retrieved,” that is, probed, during the first delayed recall test. The data for both the quiescence and task groups are shown. Distance of error refers to the deviation in location from the initially presented location of each item. Error bars show the standard error of the mean. Full lines show between-group comparisons (quiescence vs. task) of distance of error (in centimeters) scores, and dashed lines show within-subject comparisons (retrieved vs. nonretrieved).Our data reveal comparable delayed recall performance for recently retrieved item locations in participants who rested quietly after retrieval and those who played a spot-the-difference game after retrieval (see the “retrieved” data in Fig. 2). Although these findings could suggest that awake quiescence had no effect on the reconsolidation of item-location memories, methodological shortfalls (discussed below) render this conclusion unlikely. However, we did find an unforeseen beneficial effect of quiescence for nonretrieved versus retrieved photo locations: Those who experienced the spot-the-difference game in the second delay phase demonstrated significant forgetting of nonretrieved items relative to retrieved items, whereas those who experienced awake quiescence in the second delay phase did not demonstrate such forgetting (see the “nonretrieved” data in Fig. 2). We discuss these two key findings in turn.Why did we not observe any effects of postretrieval awake quiescence on reconsolidation in our study? One possibility is that, unlike sleep, awake quiescence simply does not benefit reconsolidation. A much more likely possibility is that methodological shortfalls mean that our study did not in fact probe reconsolidation. This may be true for a few reasons. First, sometimes retrieval is not sufficient to reactivate memories and reintroduce them into a labile state (e.g., Cammarota et al. 2004; Forcato et al. 2009). In fact, the protective effect of retrieval against forgetting is well documented, even over a delay of a few minutes (Karpicke and Roediger 2008; Roediger and Butler 2011), possibly because it provides a “fast route to consolidation” of new memories (Antony et al. 2017). Notwithstanding the power of retrieval to boost memory, the research discussed earlier shows that memories reactivated via retrieval can (still) benefit from postretrieval sleep. Do these studies differ from our own with regards to memory reactivation? Possibly, reactivation in our study occurred after a short delay (10 min). It is possible that retrieval was so effective at protecting against forgetting in our study because it occurred shortly after encoding and during the initial consolidation of memory traces. Indeed, studies investigating the role of different treatments (e.g., sleep, pharmaceuticals) in reconsolidation typically require participants to retrieve previously encoded memories after a much longer delay period (several hours to days). After lengthy delays such as those, encoded memories would be expected to have completed initial consolidation, or at least be much further along in the consolidation process than in our study. The 10-min delay in our study might simply have been too short for memories to consolidate sufficiently to be relabilized again. As a result, retrieval might have simply strengthened memories against forgetting and did not sufficiently return them to a labile state. These methodological shortfalls mean that our study is unlikely to have probed reconsolidation effectively. Therefore, we cannot conclude whether postretrieval awake quiescence benefits the reconsolidation of episodic memories.How can we explain the unforeseen finding that “postretrieval” awake quiescence protected against subsequent forgetting for nonretrieved (control) items, which were not probed in the first delayed recall test? Our data reveal an effect of delayed rest that was on par with the overall beneficial effect of retrieval-mediated memory reactivation (i.e., the well-established effect of retrieval practice; see above). The findings suggest that in the task group, the lack of reactivation for nonretrieved items in the first delayed recall test negatively affected these memories. However, in the quiescence group, this lack of reactivation was offset by delayed rest, which seemingly had a similarly beneficial effect on nonretrieved memories. It is unlikely that this benefit of delayed rest can be explained by intentional rehearsal. The occurrence of quiet rest after a 10-min filled delay, as opposed to immediately after encoding, makes it unlikely that participants rehearsed the nonretrieved items during the rest period because they would require explicit knowledge that they had been tested on only half of the encoded items in the first delayed recall test and spend their time rehearsing what they could recall from the subset of items that were not tested. While this does not rule out rehearsal completely, our findings reinforce recent data (e.g., Dewar et al. 2014) showing that rest-related enhancements in memory cannot simply be explained by intentional rehearsal. A consolidation account can provide a more likely explanation.Previous research on the beneficial effect of awake quiescence on memory has focused on immediate rest (i.e., rest periods occurring immediately following encoding) (Dewar et al. 2007, 2012, 2014; Craig et al. 2015, 2016; Mercer 2015; Brokaw et al. 2016; Craig and Dewar 2018; Humiston and Wamsley 2018; Sacripante et al. 2019). The rationale for this focus has been that new memories are most labile upon their initial formation (Mednick et al. 2011; Wixted and Cai 2013), and thus, supportive or disruptive interventions applied during this time should be most effective. The findings of the current study suggest that the effect of awake quiescence is sufficiently powerful to influence new memories even 10–20 min after encoding, that is, when memories have—presumably—benefited from some initial consolidation and are no longer highly labile. Moreover, they indicate that awake quiescence can support the consolidation of new memories even if the awake quiescence occurs after a period of task engagement rather than immediately after encoding. The latter hypothesis resonates with the view that consolidation is an opportunistic process (Mednick et al. 2011) and raises interesting questions about how late the onset of rest would need to be for it to no longer facilitate the consolidation of new memories. This remains to be established, but we predict that the benefit of quiescence should diminish in accordance with increasing delay in the onset of the rest period as memories are increasingly stabilized through consolidation that occurs independently of that during intentional rest. Investigation of this question may provide insights into the initial timeline of episodic memory consolidation, which is characterized poorly. Thus, more work is required to establish whether a relationship exists between the precision of item location memory and the time lag between initial encoding and postencoding quiescence.In summary, methodological shortfalls mean that we failed to probe the possible effect of awake quiescence on episodic memory reconsolidation. Nonetheless, we unexpectedly revealed that awake quiescence following encoding reduces forgetting, even when experienced at a delayed point in time and following a period of task engagement. This finding indicates that awake quiescence need not commence immediately following encoding to benefit memory consolidation, at least for object location memories. Further investigation and independent replication of this effect are required to better understand the underlying mechanisms and implications of our unexpected finding.     

Examination of the bidirectional influences of leisure activity and memory in old people: A dissociative effect on episodic memory

The present study examined the relationships between different types of social and cognitive activities and different types of episodic and semantic memory. A total of 794 adult men and women from five age cohorts (aged 65–85 at baseline), participating in the longitudinal Betula project on ageing, memory, and health, were included in the study. The participants were studied over 10 years (1995–2005) in three waves. Recognition and recall were used as episodic memory tasks, and knowledge and verbal fluency as semantic memory tasks. The results, after controlling for age, gender, education, and some diseases, including heart disease and hypertension, as covariates, showed unidirectional effects of social activity on episodic memory on all test occasions (β = .10). Also, episodic memory predicted change in cognitive activity for all test waves (β = .21–.22). Findings suggest that social activity can be seen as protective factor against memory decline. It also seems that episodic memory performance is a predictor of cognitive activity in old people. However, the opposite direction does not hold true.     

The role of episodic and semantic memory in episodic foresight

In this paper we describe a special form of future thinking, termed “episodic foresight” and its relation with episodic and semantic memory. We outline the methodologies that have largely been developed in the last five years to assess this capacity in young children and non-human animals. Drawing on Tulving's definition of episodic and semantic memory, we provide a critical analysis of the role that both types of memory might have on the episodic foresight tasks described in the literature. We conclude by highlighting some unanswered questions and suggesting future directions for research that could further our understanding of how memory is intimately connected to episodic foresight.     

Retrieval processing and episodic memory

The emergence of brain imaging has had a major impact on research into the cognitive and neural bases of human memory. An area in which this impact has been particularly strong is retrieval processing - the processes engaged when attempting to retrieve information during a memory test. Several different classes of retrieval process - such as 'mode', 'effort' and 'success' - have been invoked to account for findings from neuroimaging studies of episodic retrieval. In this article we discuss how these different kinds of process, along with a fourth kind associated with 'retrieval orientation', can be investigated in brain imaging experiments. We then review studies of retrieval processing, and assess how well their designs match up to our proposed criteria for dissociating the neural correlates of different classes of retrieval process. We conclude that few studies have used designs that permit these different kinds of process to be independently identified, and that presently there is little evidence to indicate which kinds of processing can be fractionated in terms of their neural correlates.     

Vantage point in episodic memory

University undergraduates undertook a series of manual tasks (e.g., shaping objects out of clay) and later recalled the experiences they had while doing so from either afield or anobserver vantage point. In the former case, the subjects mentally reinstated the original task environment as if they were seeing it again through their own eyes; in the latter condition, the original task environment was envisioned from the perspective of a detached spectator. Analysis of the subjects’ recollections revealed marked differences in the contents of field and observer memories. For instance, whereas field memories afforded richer accounts of the affective reactions, physical sensations, and psychological states that the subjects experienced as they performed the tasks, observer memories included more information about how the subjects looked, what they did, or where things were. Discussion focuses on prospects for future research whose aim would be to investigate the forensic and clinical implications of the field/observer distinction.     

Retrieval-induced forgetting in episodic memory

Participants learned the locations of 12 stimuli that were uniquely colored but could be grouped by shape (4 circles, 4 triangles, 4 crosses). Following the study, a retrieval-practice phase required participants to recall the colors of a subset of the stimuli (i.e., 2 circles, 2 triangles) using shape and location as cues. In a final test, participants recalled the colors of all 12 stimuli. Compared with the control set of stimuli (i.e., 4 crosses), memory was facilitated for practiced items but impaired for related items, which were not practiced but shared the same shape group. Across experiments, retrieval-induced forgetting was observed for different perceptual groupings and for different cuing procedures. The effect, however, required retrieval of information during the interpolated phase. Providing extra presentations did not disrupt memory for related items.     

Gender differences in episodic memory

The relationship between gender and memory has been largely neglected by research, despite occasional studies reporting gender differences in episodic memory performance. The present study examined potential gender differences in episodic memory, semantic memory, primary memory, and priming. Five hundred thirty women and 470 men, randomly sampled from the city of Umeå, Sweden, 35–80 years of age, participated in the study. There were no differences between men and women with regard to age or education, or on a measure of global intellectual functioning. As has been demonstrated previously, men outperformed women on a visuospatial task and women outperformed men on tests of verbal fluency. In addition, the results demonstrated that women consistently performed at a higher level than did men on the episodic memory tasks, although there were no differences between men and women on the tasks assessing semantic memory, primary memory, or priming. The women’s higher level of performance on the episodic memory tasks could not be fully explained by their higher verbal ability.     

Adaptive scaling of reward in episodic memory: a replication study

Reward is thought to enhance episodic memory formation via dopaminergic consolidation. Bunzeck, Dayan, Dolan, and Duzel [(2010). A common mechanism for adaptive scaling of reward and novelty. Human Brain Mapping, 31, 1380–1394] provided functional magnetic resonance imaging (fMRI) and behavioural evidence that reward and episodic memory systems are sensitive to the contextual value of a reward—whether it is relatively higher or lower—as opposed to absolute value or prediction error. We carried out a direct replication of their behavioural study and did not replicate their finding that memory performance associated with reward follows this pattern of adaptive scaling. An effect of reward outcome was in the opposite direction to that in the original study, with lower reward outcomes leading to better memory than higher outcomes. There was a marginal effect of reward context, suggesting that expected value affected memory performance. We discuss the robustness of the reward memory relationship to variations in reward context, and whether other reward-related factors have a more reliable influence on episodic memory.     

Cognitive neuroscience of episodic memory encoding

This paper presents a cognitive neuroscientific perspective on how human episodic memories are formed. Convergent evidence from multiple brain imaging studies using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) suggests a role for frontal cortex in episodic memory encoding. Activity levels within frontal cortex can predict episodic memory encoding across a wide range of behavioral manipulations known to influence memory performance, such as those present during levels of processing and divided attention manipulations. Activity levels within specific frontal and medial temporal regions can even predict, on an item by item basis, whether an episodic memory is likely to form. Furthermore, separate frontal regions appear to participate in supplying code-specific information, including distinct regions which process semantic attributes of verbal information as well as right-lateralized regions which process nonverbal information. We hypothesize that activity within these multiple frontal regions provides a functional influence (input) to medical temporal regions that bind the information together into a lasting episodic memory trace.     

Age and active navigation effects on episodic memory: A virtual reality study

We investigated the navigation‐related age effects on learning, proactive interference semantic clustering, recognition hits, and false recognitions in a naturalistic situation using a virtual apartment‐based task. We also examined the neuropsychological correlates (executive functioning [EF] and episodic memory) of navigation‐related age effects on memory. Younger and older adults either actively navigated or passively followed the computer‐guided tour of an apartment. The results indicated that active navigation increased recognition hits compared with passive navigation, but it did not influence other memory measures (learning, proactive interference, and semantic clustering) to a similar extent in either age group. Furthermore, active navigation helped to reduce false recognitions in younger adults but increased those made by older adults. This differential effect of active navigation for younger and older adults was accounted for by EF score. Like for the subject‐performed task effects, the effects from the navigation manipulation were well accounted for by item‐specific/relational processing distinction, and they were also consistent with a source monitoring deficit in older adults.     

Bio-inspired cognitive architecture of episodic memory

Memory and learning are essential functions in human beings as they allow us to acquire and store in the brain representations of thoughts, experiences, and behaviors, which are required for problem-solving in our daily life and mainly for survival. Episodic memory is a type of memory that provides the ability to re-experience events in one’s life, and it is associated with their conscious recollection. Since episodic memory can represent our experiences about the environment, similar to a mental journey, it is desired in systems that attempt to create human-like behavior. Currently, the main problem is that state of the art proposals do not consider neuroscientific evidence like memory dynamics for forgetting or bottom-up inputs, and most of them do not consider episodic memory as a different memory but as part of general declarative memory. We consider these omissions to limit the generation of human-like behavior. In this work, we propose a bio-inspired cognitive architecture of episodic memory. Neuroscientific evidence provides us with the brain structures associated with this type of memory, the connections, and the operations these areas perform. We hypothesize that virtual entities endowed with our episodic memory cognitive architecture will plan and make decisions in a more human-like fashion. To test the capabilities of the proposal, we endowed a virtual creature with a distributed and concurrent implementation of our architecture, and it was given two tasks. The first task validated the functions of the memory independently, and in the second task, the creature used episodic memory to solve a planning problem. From the results of these experiments, we validate our proposal and show that it is possible to create a system that behaves as the human brain does.     

Editing episodic memory following the identification of error

The editing of an episodic memory record in order to remove incorrect information embedded within naturalistic communications is an important though underinvestigated phenomenon. Experiment 1 deals with the recall and comprehension of a sequence of messages following the delayed identification of one of the messages as being incorrect. Two styles of correction were employed, and it was found that in neither case was the memory record edited effectively. Inferences based upon the old information continued to be drawn although subjects had clearly recalled that it had been subsequently corrected.

Experiment 2 showed that editing could be effective if the old information did not play a central role in the message sequence. It is concluded that the observed difficulties in editing arise when old information has to be excised from the episodic record; the uncontested insertion of new information retrospectively did not present the same difficulty.

Reading span was used to monitor subjects' editing strategies, and from its association with performance measures it is concluded that contradictions in the memory record are not dealt with immediately but are resolved locally when comprehension is questioned. At this time inferences are drawn based upon the most recent version of the contradictory messages. This recency strategy breaks down when the old information provides a better fit to the question posed. Some implications of these findings for models of memory storage are discussed.