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.     

A Comparison of Preschoolers' Memory,Knowledge, and Anticipation of Events

This study examined the development of the episodic and semantic memory systems, with an emphasis on the emergence of the two aspects of the former: episodic memory (the ability to re-experience a past event) and episodic future thinking (the ability to pre-experience a future event). Three-, 4-, and 5-year olds were randomly assigned to one of three conditions: past, semantic, or future. Children were asked questions about the same eight events, phrased in past, generalized present, or future tense. Half of these events were ones for which parents rated their children as having a high level of control (or input) over how the event unfolds, whereas the other half were rated as “low control.” Responses were scored with respect to their specificity and accuracy. Results revealed age differences in children's accuracy scores across all three conditions. Children's episodic future thinking and episodic memory, but not semantic memory, were less accurate for low-control events compared with high-control events. These results offer a new perspective on the development of the episodic and semantic memory systems and the methods used to assess them.     

Commitment in romantic relationships as a function of partners’ encoding of important couple-related memories

The purpose of the present study was to investigate how significant couple-related events are encoded in the episodic memory of each partner of a romantic relationship and how they relate to each of these partners’ level of commitment in an independent and additive fashion. Each partner of a couple reported a significant couple-related memory and rated their level of need satisfaction experienced during the event of the memory. In addition, each partner was shown his/her partner’s memory and also rated their own level of need satisfaction for this event. Results showed that partners need satisfaction ratings of their own memory positively predicted their own commitment to the relationship directly (for women) as well as through their need satisfaction generally experienced in the relationship (for men). In addition, men’s need satisfaction ratings of their own memory were associated with women’s commitment while controlling for women’s need satisfaction ratings of men’s memory, but no such cross-partner effects were found for women. Overall, the findings shed light on an initial understanding of how a person’s own memory of an event can impact another person’s attitudes even when taking into account this other person’s memory encoding of that same event.     

A “snapshot” of declarative memory: Differing developmental trajectories in episodic and autobiographical memory

Episodic and autobiographical memory are clearly related, yet in both the adult and developmental literatures it is difficult to compare them because of differences in how the constructs are assessed, including differences in content, levels of control, and time since experience. To address these issues, we directly compared children's and adults’ autobiographical and episodic memory using the same controlled paradigm. Participants engaged in a photo-taking activity in a museum (autobiographical encoding) and viewed others’ photographs of the same museum exhibits (episodic encoding). At test, participants classified photos as ones they took, viewed, or novel. In the autobiographical condition older children and adults performed similarly; younger children's performance was lower than adults’. In contrast, in the episodic condition both groups of children performed more poorly than adults. The findings suggest the developmental primacy of autobiographical relative to episodic memory, and that traditional episodic tasks may underestimate older children's declarative memory abilities.     

Animal models of source memory

Source memory is the aspect of episodic memory that encodes the origin (i.e., source) of information acquired in the past. Episodic memory (i.e., our memories for unique personal past events) typically involves source memory because those memories focus on the origin of previous events. Source memory is at work when, for example, someone tells a favorite joke to a person while avoiding retelling the joke to the friend who originally shared the joke. Importantly, source memory permits differentiation of one episodic memory from another because source memory includes features that were present when the different memories were formed. This article reviews recent efforts to develop an animal model of source memory using rats. Experiments are reviewed which suggest that source memory is dissociated from other forms of memory. The review highlights strengths and weaknesses of a number of animal models of episodic memory. Animal models of source memory may be used to probe the biological bases of memory. Moreover, these models can be combined with genetic models of Alzheimer's disease to evaluate pharmacotherapies that ultimately have the potential to improve memory.     

Mental time travel: Effects of trial duration on episodic and semantic content

Studies exploring mental time travel commonly use cue-word paradigms to elicit past and future autobiographical events. However, the effect of trial duration (how long participants are allowed to describe events) on the relationship between episodic and nonepisodic detail and episodic specificity (i.e., whether longer durations increase event specificity) has not been examined. To resolve these issues, a cue-word study was devised whereby participants described past and future events under three randomly administered time constraints: short (1-min), standard (3-min), and long (5-min) durations. Findings indicated that an individual's capacity for episodic and nonepisodic thought for the past and future were unrelated. This lends supports to the idea that independent mechanisms are responsible for episodic and semantic information. This study also offers clarity concerning the effect of different trial durations on episodic specificity, which may aid the design of future studies of mental time travel.     

Episodic future thinking in children compared to adolescents

Episodic thinking involves the ability to re-create past and to construct future personal events, which contain event-specific (episodic) and general (semantic) details. The richness of episodic thought for past events improves as children move into adolescence. The current study aims to examine changes in episodic future thinking and to establish the cognitive underpinning of these changes. Typically developing children (n = 14) and adolescents (n = 15) were tested using an adapted version of the Child Autobiographical Interview (CAI) that required generation of past and future personally relevant events. Relational memory and executive skills were also examined. Significant developmental gains were found in richness of events recall across temporal directions (past and future) and across different types of details (episodic and semantic). Developmental gains in richness of past events were also shown to correspond to developmental gains in generation of future events. Moreover, developmental changes in relational memory and (to a lesser extent) executive functions were found to relate to increases in the amount of episodic (but not semantic) details provided. Our study highlighted the similarities between past and future episodic thinking in typically developing children and adolescents. It also raises a possibility that children with developmental and neurological disorders with impaired relational memory and/or executive skills may be at risk of difficulties with episodic thinking.     

Coding of stimuli by animals: Retrospection, prospection, episodic memory and future planning

When animals code stimuli for later retrieval they can either code them in terms of the stimulus presented (as a retrospective memory) or in terms of the response or outcome anticipated (as a prospective memory). Although retrospective memory is typically assumed (as in the form of a memory trace), evidence of prospective coding has been found when response intentions and outcomes are particularly salient. At a more abstract level is the question of whether animals are able figuratively to travel back in time to recover memories of past events (episodic memory) and forward in time to predict future events (future planning). Although what would constitute adequate evidence of episodic memory and future planning is controversial, preliminary evidence suggests that animals may be capable of both forms of subjective time travel.     

Making the future memorable: The phenomenology of remembered future events

Although our ability to remember future simulations conveys an adaptive advantage, enabling us to better prepare for upcoming events, the factors influencing the memorability of future simulations are not clear. In this study, participants generated future simulations that combined specific people, places and objects from memory, and for each trial, made a series of phenomenological ratings about the event components and the simulation as a whole. Memory for simulations was later assessed using a cued-recall test. We used multilevel modelling to determine whether the phenomenological qualities of event components (familiarity, emotionality and significance) and simulations (detail, plausibility) were predictive of whether the simulation was successfully encoded and later accessible. Our results demonstrate that person familiarity, detail and plausibility were significant predictors of whether a given future simulation was encoded into memory and later accessible. These findings suggest that scaffolding future simulations with pre-existing episodic memories is the path to a memorable future.     

Introspection &; remembering

We argue that episodic remembering, understood as the ability to re-experience past events, requires a particular kind of introspective ability and understanding. It requires the understanding that first person experiences can represent actual events. In this respect it differs from the understanding required by the traditional false belief test for children, where a third person attribution (to others or self) of a behavior governing representation is sufficient. The understanding of first person experiences as representations is also required for problem solving with images. In support of this argument we review developmental evidence that children’s episodic remembering is independent of and emerges after mastery of the false belief task but emerges together with the use of imagery for solving visual rotation tasks.     

Did the popsicle melt? Preschoolers’ performance in an episodic-like memory task

Episodic memory has been tested in non-human animals using depletion paradigms that assess recollection for the “what”, “where” and “when” (i.e., how long ago). This paradigm has not been used with human children, yet doing so would provide another means to explore their episodic memory development. Using a depletion paradigm, preschool-aged children were presented in two trials with a preferred food that was only edible after a short interval and a less-preferred food that was edible after the short and long intervals. Younger (mean?=?40 months) and older (mean?=?65 months) children tended to choose their preferred food after the short intervals, but did not switch to selecting their less-preferred food after the long intervals. Importantly, their choices did not differ with age. Although older children better remembered “what”, “where”, and “what is where” than did younger children, neither age group successfully estimated “how long ago” an event occurred. Finally, both age groups spontaneously recalled information about Trial 1. We also analysed the relation between the different measures used in the study but no clear patterns emerged. Results are discussed with respect to the cognitive mechanisms necessary to succeed in depletion paradigms and the measurement of episodic memory more broadly.     

Accessibility and characteristics of memories of the future

Recent research suggests that some imagined future events are encoded in memory, leading to the formation of “memories of the future”. However, questions remain regarding the exact components of future event simulations that are encoded and the factors that determine their accessibility. To address these questions, the present study investigated memory for previously imagined future events using both free and cued recall tasks. The results showed that most future event simulations were successfully encoded and remained available in memory after a one week delay, but only some of them were readily accessible, whereas others could only be accessed when relevant cues were provided. Persons and locations were particularly well remembered, suggesting that these components are central to the simulation and memorisation of future events. We also found that memory for future event simulations was related to the clarity and familiarity of represented persons, the subjective feelings of pre-experience and mental time travel, the importance of imagined events to personal goals, and their emotional intensity during the initial simulation phase. Taken together, these findings expand our understanding of the formation, accessibility, and characteristics of memories of the future.     

Imagining novel futures: The roles of event plausibility and familiarity

The constructive episodic simulation hypothesis suggests that episodic memory supports the simulation of future events through extraction and recombination of stored information. The current study explicitly investigated the use of past episodic thought in the simulation of future scenarios. Participants simulated one of three possible scenarios, differing in plausibility and participants’ prior experience of similar events. Participants recorded related memories and whether they were explicitly used during future event simulation. Memories were rated for source (self-experienced, other-experienced, or media). Findings suggest prior experience and event plausibility did not impact upon ease of future event simulation or the extent of memory usage during simulations. Differences emerged in the source of information used to assist future event simulation. These findings provide support for the hypothesis that episodic memories from a variety of sources are recombined when generating future simulations of novel events.     

Content-specific phenomenological similarity between episodic memory and simulation

ABSTRACT

Numerous studies have indicated that remembering specific past experiences (i.e., episodic memory) and imagining specific novel future experiences (i.e., episodic simulation) are supported by common mental processes. An open question, however, is whether and to what extent the content of specific past episodes is sampled when simulating a specific future episode. The current study aimed to answer this question. Participants recalled past episodes each comprising two episodic details, a personally familiar location and person. Participants also simulated novel future episodes using recombined pairs of person and location details taken from different recalled episodes. Participants rated the vividness of each location and person in their memory and simulation. We conducted a multi-level analysis where the vividness rating during memory was used to predict the vividness rating during simulation at the level of individual shared details (i.e., location or person). The vividness of the memorial detail co-varied with the vividness of the simulated detail; this relationship persisted even after accounting for the underlying familiarity of the details. These findings strongly suggest that simulations of specific future experiences are based upon the contents of specific prior episodes.     

自我相关未来思考:两种基本类型及其主要心理成分比较

自我相关未来思考是个体产生自我相关未来想法的心理加工,它包括未来情景思考和未来个人语义思考两种基本类型。两类思考都需记忆、自我和主观时间三种主要心理成分参与,但参与的具体形式可能有所不同:未来情景思考可能主要依赖于情景记忆和语义记忆、情景自我知识和语义自我知识、经验时间;未来个人语义思考可能主要依赖于语义记忆、语义自我知识和知道时间。三种主要心理成分在两种思考类型中的作用可能是相同的,其中,记忆是原材料,自我起引导作用,主观时间是先决条件。将来可以参照思考未来公众抽象问题的研究进一步明确自我和记忆在未来个人语义思考中的作用,还可以通过探究不同心理成分内部及成分间的交互作用进而了解各成分在自我相关未来思考中的作用机制。     

The association between past and future oriented thinking: Evidence from autism spectrum disorder

A number of recently developed theories (e.g., the constructive episodic simulation, self-projection, and scene construction hypotheses) propose that the ability to simulate possible future events (sometimes referred to as episodic future thinking, prospection, or foresight) depends on the same neurocognitive system that is implicated in the recall of past events (episodic memory). In this paper, we argue that autism spectrum disorder (ASD) offers an ideal test of such theories, given that it is a developmental disorder that is characterized by impairments in episodic memory. Each of these theories would predict concomitant impairments in episodic future thinking among individuals with ASD. We review evidence concerning episodic future thinking in ASD, as well as studies of prospective memory (remembering to do something in the future), planning, navigation, and theory of mind, which some theories suggest also rely on the same mechanism as episodic future thinking.     

"When did I learn and when shall I act?": The developmental relationship between episodic future thinking and memory

This study investigated the development of the ability to reflect on one’s personal past and future. A total of 64 4- to 6-year-olds received tasks of delayed self-recognition, source memory, delay of gratification, and a newly developed task of future-oriented action timing. Although children’s performance on delayed self-recognition, source memory, and action timing improved with age, their performance on delay of gratification did not. Children’s errors in source memory and action timing were solely and strongly associated with each other in older children (5–6 years) even after controlling for age and verbal ability. Results are discussed in terms of mental time travel underlying episodic memory and future thinking that includes both the projection of oneself into the past and future and the appreciation of events’ temporal relations.