Remembering the past and imagining the future: Examining the consequences of mental time travel on memory

Cognitive, neuropsychological, and neuroimaging evidence suggests that remembering the past and imagining the future rely on overlapping processes in episodic memory. The three experiments reported here examine the consequences of remembering the past and imagining the future on the accessibility of other information in memory. Participants first studied events associated with a specific context and then either (a) retrieved past autobiographical events associated with that same context or (b) imagined future autobiographical events associated with that same context. Replicating and extending evidence of retrieval-induced forgetting, remembering autobiographical events from the past caused participants to forget the related studied events. However, imagining future autobiographical events failed to cause participants to forget the related studied events. These results suggest an important difference in the memorial consequences of remembering and imagining.     

Reduced goal specificity is associated with reduced memory specificity in depressed adults

Models of autobiographical memory suggest a close association between memories, future imagination and setting specific personal goals. However this association has yet to be tested with depressed individuals. The aim of this study was to examine whether the specificity of remembering past and imagining future personal events is associated with the specificity of approach and avoidance goals in depressed individuals. Two samples comprising adults who met criteria for major depressive disorder (MDD; N=30) and adults who had no prior history or current depression (N=30) completed autobiographical memory and future event tests, and a personal goal task. In the depressed sample, the specificity with which participants remembered the past was significantly associated with the specificity with which they generated future goals. The depressed sample also elicited fewer specific approach and avoidance goals compared to the non-depressed sample. These findings suggest that an overgeneral memory deficit extends to impairments in goal specificity.     

Priming,not inhibition,of related concepts during future imagining

Remembering the past and imagining the future both involve the retrieval of details stored in episodic memory and rely on the same core network of brain regions. Given these parallels, one might expect similar component processes to be involved in remembering and imagining. While a strong case can be made for the role of inhibition in memory retrieval, few studies have examined whether inhibition is also necessary for future imagining and results to-date have been mixed. In the current study, we test whether related concepts are inhibited during future imagining using a modified priming approach. Participants first generated a list of familiar places and for each place, the people they most strongly associate with it. A week later, participants imagined future events involving recombinations of people and places, immediately followed by a speeded response task in which participants made familiarity decisions about people’s names. Across two experiments, our results suggest that related concepts are not inhibited during future imagining, but rather are automatically primed. These results fit with recent work showing that autobiographically significant concepts (e.g., friends’ names) are more episodic than semantic in nature, automatically activating related details in memory and potentially fuelling the flexible simulation of future events.     

Remembering,imagining, false memories & personal meanings

The Self-Memory System encompasses the working self, autobiographical memory and episodic memory. Specific autobiographical memories are patterns of activation over knowledge structures in autobiographical and episodic memory brought about by the activating effect of cues. The working self can elaborate cues based on the knowledge they initially activate and so control the construction of memories of the past and the future. It is proposed that such construction takes place in the remembering–imagining system – a window of highly accessible recent memories and simulations of near future events. How this malfunctions in various disorders is considered as are the implication of what we term the modern view of human memory for notions of memory accuracy. We show how all memories are to some degree false and that the main role of memories lies in generating personal meanings.     

Eye movements disrupt episodic future thinking

Remembering the past and imagining the future both rely on complex mental imagery. We considered the possibility that constructing a future scene might tap a component of mental imagery that is not as critical for remembering past scenes. Whereas visual imagery plays an important role in remembering the past, we predicted that spatial imagery plays a crucial role in imagining the future. For the purpose of teasing apart the different components underpinning scene construction in the two experiences of recalling episodic memories and shaping novel future events, we used a paradigm that might selectively affect one of these components (i.e., the spatial). Participants performed concurrent eye movements while remembering the past and imagining the future. These concurrent eye movements selectively interfere with spatial imagery, while sparing visual imagery. Eye movements prevented participants from imagining complex and detailed future scenes, but had no comparable effect on the recollection of past scenes. Similarities between remembering the past and imagining the future are coupled with some differences. The present findings uncover another fundamental divergence between the two processes.     

Episodic future thought: Contributions from working memory

The ability to imagine hypothetical events in one’s personal future is thought to involve a number of constituent cognitive processes. We investigated the extent to which individual differences in working memory capacity contribute to facets of episodic future thought. College students completed simple and complex measures of working memory and were cued to recall autobiographical memories and imagine future autobiographical events consisting of varying levels of specificity (i.e., ranging from generic to increasingly specific and detailed events). Consistent with previous findings, future thought was related to analogous measures of autobiographical memory, likely reflecting overlapping cognitive factors supporting both past and future thought. Additionally, after controlling for autobiographical memory, residual working memory variance independently predicted future episodic specificity. We suggest that when imagining future events, working memory contributes to the construction of a single, coherent, future event depiction, but not to the retrieval or elaboration of event details.     

Separating past and future autobiographical events in memory: Evidence for a reality monitoring asymmetry

After thinking about the past and imagining the future, how do people separate these real and imagined events in memory? We had subjects engage in past and future autobiographical elaboration, then later take memory tests that required them to recollect these earlier generated events. In Experiment 1, testing memory for previously generated past or future autobiographical events led to fewer source memory confusions than did an elaborative control task, suggesting that the distinctive features of autobiographical elaboration improved subsequent retrieval monitoring accuracy. In Experiment 2, we directly compared retrieval monitoring accuracy for previously generated past and future autobiographical events and found that subjects made fewer source confusions when searching memory for future events. This asymmetry suggests that the features characterizing future elaborations (e.g., cognitive operations) were used more effectively during reality monitoring than were the features characterizing past elaborations (e.g., perceptual details), and has implications for future-oriented theories of memory.     

Emotional intensity in episodic autobiographical memory and counterfactual thinking

Episodic counterfactual thoughts—imagined alternative ways in which personal past events might have occurred—are frequently accompanied by intense emotions. Here, participants recollected positive and negative autobiographical memories and then generated better and worse episodic counterfactual events from those memories. Our results suggest that the projected emotional intensity during the simulated remembered/imagined event is significantly higher than but typically positively related to the emotional intensity while remembering/imagining the event. Furthermore, repeatedly simulating counterfactual events heightened the emotional intensity felt while simulating the counterfactual event. Finally, for both the emotional intensity accompanying the experience of remembering/imagining and the projected emotional intensity during the simulated remembered/imagined event, the emotional intensity of negative memories was greater than the emotional intensity of upward counterfactuals generated from them but lower than the emotional intensity of downward counterfactuals generated from them. These findings are discussed in relation to clinical work and functional theories of counterfactual thinking.     

老年人对情绪性事件的情景模拟:回忆过去与想象未来

研究采用自传体访谈技术,首次考察了老年人在对情绪性事件进行回忆和想象中生成的内部细节和外部细节数量,及其对回忆和想象内容的主观评估。结果发现:(1)无论是回忆还是想象任务,老年人都比年轻人提供了更少的内部细节和略多的外部细节;(2)与年轻人相似,老年人在想象未来积极事件时产生了更多的内部细节,表现出对积极信息的加工偏好;(3)老年人比年轻人更倾向于认为想象的事件与过去发生的事件相似度高,表明该群体在想象过程中更多地依赖了过去的记忆。该结果揭示了老年人对情绪性事件的回忆和想象特点,说明在回忆和想象过程中出现的与年龄有关的缺陷同样会体现在情绪性事件中,这很好地支持了建构性情景模拟假说。     

The differential contributions of visual imagery constructs on autobiographical thinking

There is a growing theoretical and empirical consensus on the central role of visual imagery in autobiographical memory. However, findings from studies that explore how individual differences in visual imagery are reflected on autobiographical thinking do not present a coherent story. One reason for the mixed findings was suggested to be the treatment of visual imagery as an undifferentiated construct while evidence shows that there is more than one type of visual imagery. The present study investigates the relative contributions of different imagery constructs; namely, object and spatial imagery, on autobiographical memory processes. Additionally, it explores whether a similar relation extends to imagining the future. The results indicate that while object imagery was significantly correlated with several phenomenological characteristics, such as the level of sensory and perceptual details for past events – but not for future events – spatial imagery predicted the level of episodic specificity for both past and future events. We interpret these findings as object imagery being recruited in tasks of autobiographical memory that employ reflective processes while spatial imagery is engaged during direct retrieval of event details. Implications for the role of visual imagery in autobiographical thinking processes are discussed.     

Emotion regulation during social remembering: differences between emotions elicited during an event and emotions elicited when talking about it

This paper examines emotion regulation as a function of autobiographical remembering in social contexts. Two studies (n = 38 and 123, respectively) are presented that provide evidence that autobiographical remembering in social settings can result in changes in the emotions associated with an experience. However, the results also suggest that whether changes occur depends on features of the recall context, including the gender of participants, and the responses of their listeners. Across both studies, men showed greater emotional benefits from talking about events than women. Moreover, greater listener agreement was associated with greater benefits for emotion. The results are discussed in terms of functions of autobiographical remembering, gender, social support, and emotion regulation.     

Directed forgetting of autobiographical memory in mild Alzheimer's disease

Using the autobiographical directed forgetting method (Barnier et al., 2007), the present paper addressed the intentional inhibitory processes of episodic and semantic autobiographical memory in Alzheimer's disease (AD). Mild AD patients and healthy elderly people were instructed to either forget or to continue remembering previously generated autobiographical events. In a later recall test they were asked to reconstruct the early-generated memories regardless of the forget/remember instruction. Autobiographical reconstruction was further distributed into episodic and semantic memories. Results showed no forget instruction effect on episodic or semantic autobiographical recall with AD patients, whereas healthy elderly people were able to inhibit only episodic autobiographical memories. The findings suggest an impairment of the intentional inhibitory processes in autobiographical memory with AD and a relative preservation of these mechanisms with normal ageing. They also demonstrate an earlier decline in the intentional inhibitory processes compared to the autobiographical deterioration in AD.     

Directed forgetting of autobiographical memory in mild Alzheimer's disease

Using the autobiographical directed forgetting method (Barnier et al., 2007), the present paper addressed the intentional inhibitory processes of episodic and semantic autobiographical memory in Alzheimer's disease (AD). Mild AD patients and healthy elderly people were instructed to either forget or to continue remembering previously generated autobiographical events. In a later recall test they were asked to reconstruct the early-generated memories regardless of the forget/remember instruction. Autobiographical reconstruction was further distributed into episodic and semantic memories. Results showed no forget instruction effect on episodic or semantic autobiographical recall with AD patients, whereas healthy elderly people were able to inhibit only episodic autobiographical memories. The findings suggest an impairment of the intentional inhibitory processes in autobiographical memory with AD and a relative preservation of these mechanisms with normal ageing. They also demonstrate an earlier decline in the intentional inhibitory processes compared to the autobiographical deterioration in AD.     

Remembering the past and imagining the future: attachment effects on production of episodic details in close relationships

Attachment theories and studies have shown that Internal Working Models (IWMs) can impact autobiographical memory and future-oriented information processing relevant to close relationships. According to the constructive episodic simulation hypothesis (CESH), both remembering the past and imagining the future rely on episodic memory. We hypothesised that one way IWMs may bridge past experiences and future adaptations is via episodic memory. The present study investigated the association between attachment and episodic specificity in attachment-relevant and attachment-irrelevant memory and imagination among young and older adults. We measured the attachment style of 37 young adults and 40 older adults, and then asked them to remember or imagine attachment-relevant and attachment-irrelevant events. Participants’ narratives were coded for internal details (i.e., episodic) and external details (e.g., semantic, repetitions). The results showed that across age group, secure individuals generated more internal details and fewer external details in attachment-relevant tasks compared to attachment-irrelevant tasks; these differences were not observed in insecure individuals. These findings support the CESH and provide a new perspective to understand the function of IWMs.     

Individual differences in the phenomenology of mental time travel: The effect of vivid visual imagery and emotion regulation strategies

It has been claimed that the ability to remember the past and the ability to project oneself into the future are intimately related. We sought support for this proposition by examining whether individual differences in dimensions that have been shown to affect memory for past events similarly influence the experience of projecting oneself into the future. We found that individuals with a higher capacity for visual imagery experienced more visual and other sensory details both when remembering past events and when imagining future events. In addition, individuals who habitually use suppression to regulate their emotions experienced fewer sensory, contextual, and emotional details when representing both past and future events, while the use of reappraisal had no effect on either kind of events. These findings are consistent with the view that mental time travel into the past and into the future relies on similar mechanisms.