“I can see clearly now”: The effect of cue imageability on mental time travel

Mental time travel (MTT) is the ability to mentally project oneself backward or forward in time, in order to remember an event from one’s personal past or to imagine a possible event in one’s personal future. Recent work has suggested that, although past and future MTT may rely on shared neurocognitive substrates, the two temporal directions may interact differently with components of this underlying system. Here, we asked 151 participants to recall or imagine past and future autobiographical events in response to high- and low-imageable cue words. The results showed that high- and low-imageable cued events differed markedly on almost all measures, suggesting that imagery acts as a facilitator when constructing both past and possible future events. In line with previous work, future events less often referred to specific events, contained fewer details, and were more positive and idyllic than past events. However, these main effects were qualified by a number of interactions. In particular, we found an increased effect of cue imageability for past as compared to future events, suggesting that the generation of past events is more sensitive to the ability of the cues to invoke the sensory components of the encoding context, whereas the construction of future events is more driven by context-independent schemata.     

Visual imagery: The past and future as seen by patients with Alzheimer’s disease

We investigated visual imagery for past and future thinking in Alzheimer’s Disease (AD). We invited AD patients and controls to retrieve past events and to imagine future events. Participants also provided a “Field” response if they see the event through their own eyes, or an “Observer” response if they see themselves in the scene as a spectator would. Less “Field” and more “Observer” responses were observed in AD participants than in controls during past and future thinking, suggesting a diminished ability to mentally visualize past and future events in AD. Results also demonstrated significant positive correlations between the production of “Field” responses and specificity during past and future thinking, suggesting a relationship between the ability to mentally visualize past and future events and autobiographical overgenerality in AD.     

Make it real: Belief in occurrence within episodic future thought

While the cognitive and neural bases of episodic future thinking are well documented, questions remain as to what gives the sense that an imagined event belongs to one’s personal future. Capitalizing on previous research on metacognitive appraisals in autobiographical remembering, we propose that episodic future thinking involves, in varying degrees, a subjective belief in the potential occurrence of imagined future events and we explore the nature and determinants of such belief. To this aim, participants provided justifications for belief in occurrence for a series of past and future events. For each event, they also assessed their subjective feelings (belief in occurrence, autonoetic experience, and belief in accuracy) and rated various characteristics of mental representations that might contribute to these feelings. Results showed that belief in the occurrence of future events mostly related to their integration in a broader autobiographical context, especially their relevance to personal goals and their personal plausibility. We also found that belief in occurrence, autonoetic experience, and belief in accuracy represented distinct subjective appraisals of future events, which depended in part on different determinants. Based on these findings, we propose a new theoretical model of subjective feelings associated with episodic future thinking that conceives of belief in occurrence as arising from metacognitive appraisals that shape the sense that imagined events belong to one’s personal future.     

What differentiates episodic future thinking from complex scene imagery?

We investigated the contributions of familiarity of setting, self-relevance and self-projection in time to episodic future thinking. The role of familiarity of setting was assessed, in Experiment 1, by comparing episodic future thoughts to autobiographical future events supposed to occur in unfamiliar settings. The role of self-relevance was assessed, in Experiment 2, by comparing episodic future thoughts to future events involving familiar others. The role of self-projection in time was assessed, in both Experiments, by comparing episodic future thoughts to autobiographical events that were not temporal in nature. Results indicated that episodic future thoughts were more clearly represented than autobiographical future events occurring in unfamiliar setting and future events involving familiar others. Our results also revealed that episodic future thoughts were indistinguishable from autobiographical atemporal events with respect to both subjective and objective detail ratings. These results suggest that future and atemporal events are mentally represented in a similar way.     

Remembering and imagining: the role of the self

This study investigated whether temporal clustering of autobiographical memories (AMs) around periods of self-development ( [Rathbone et al., 2008] and [Rathbone et al., 2009] ) would also occur when imagining future events associated with the self. Participants completed an AM task and future thinking task. In both tasks, memories and future events were cued using participant-generated identity statements (e.g., I am a student; I will be a mother). Participants then dated their memories and future events, and finally gave an age at which each identity statement was judged to emerge. Dates of memories and future events were recoded as temporal distance from the identity statement used to cue them. AMs and future events both clustered robustly around periods of self-development, indicating the powerful organisational effect of the self. We suggest that life narrative structures are used to organise future events as well as memories.     

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.     

Children's temporal judgments for autobiographical past and future events

We compared the performance of twenty 5-7-year-olds on two spatial-temporal judgment tasks. In a semantic task, children located temporal distances from today that were described using conventional, temporal terms on a spatial timeline. In an autobiographical task, children judged temporal distances on the same spatial timeline for events that they had experienced, or were going to experience, presented without explicit temporal references. Six-year-olds were equally accurate in judging temporal distances in the semantic and autobiographical tasks, but 7-year-olds were more accurate in the semantic task. Older children were more accurate than younger children in the semantic task, but no significant age differences were found for autobiographical events. Surprisingly, children were equally accurate in locating past and future events in time. Children at both ages were more accurate judging temporal distances up to one week away (both past and future) as compared to distances of two to four weeks across both tasks. Results suggest that knowledge of recurring time patterns and conventional time measurement systems is necessary, but not sufficient, for locating autobiographical events in time, and temporal distance plays an important role in children's temporal judgments.     

Age differences in autobiographical memory across the adult lifespan: older adults report stronger phenomenology

As an individual’s life story evolves across adulthood, the subjective experience (phenomenology) of autobiographical memory likely changes. In addition to age at retrieval, both the recency of the memory and the age when a memory is formed may be particularly important to its phenomenology. The present work examines the effect of three temporal factors on phenomenology ratings: (a) age of the participant, (b) age at the event reported in the memory, and (c) memory age (recency). A large sample of Americans (N?=?1120), stratified by chronological age, recalled and rated two meaningful memories, a Turning Point and an Early Childhood Memory. Ratings of phenomenology (e.g., vividness of turning points) were higher among older adults compared to younger adults. Memories of events from the reminiscence bump were more positive in valence than events from other time periods but did not differ on other phenomenological dimensions; recent memories had stronger phenomenology than remote memories. In contrast to phenomenology, narrative content was generally unrelated to participant age, age at the event, or memory age. Overall, the findings indicate age-related differences in how meaningful memories are re-experienced.     

Age-related positivity effects and autobiographical memory detail: evidence from a past/future source memory task

This study investigated whether the age-related positivity effect strengthens specific event details in autobiographical memory. Participants retrieved past events or imagined future events in response to neutral or emotional cue words. Older adults rated each kind of event more positively than younger adults, demonstrating an age-related positivity effect. We next administered a source memory test. Participants were given the same cue words and tried to retrieve the previously generated event and its source (past or future). Accuracy on this source test should depend on the recollection of specific details about the earlier generated events, providing a more objective measure of those details than subjective ratings. We found that source accuracy was greater for positive than negative future events in both age groups, suggesting that positive future events were more detailed. In contrast, valence did not affect source accuracy for past events in either age group, suggesting that positive and negative past events were equally detailed. Although ageing can bias people to focus on positive aspects of experience, this bias does not appear to strengthen the availability of details for positive relative to negative past events.     

Age-related positivity effects and autobiographical memory detail: Evidence from a past/future source memory task

This study investigated whether the age-related positivity effect strengthens specific event details in autobiographical memory. Participants retrieved past events or imagined future events in response to neutral or emotional cue words. Older adults rated each kind of event more positively than younger adults, demonstrating an age-related positivity effect. We next administered a source memory test. Participants were given the same cue words and tried to retrieve the previously generated event and its source (past or future). Accuracy on this source test should depend on the recollection of specific details about the earlier generated events, providing a more objective measure of those details than subjective ratings. We found that source accuracy was greater for positive than negative future events in both age groups, suggesting that positive future events were more detailed. In contrast, valence did not affect source accuracy for past events in either age group, suggesting that positive and negative past events were equally detailed. Although ageing can bias people to focus on positive aspects of experience, this bias does not appear to strengthen the availability of details for positive relative to negative past events.     

Odour-induced mental time travel into the past and future: Do odour cues retain a unique link to our distant past?

Proustian memories, or memories spontaneously evoked by taste and odours, have been argued to be uniquely linked to our remote past. This view suggests an asymmetry between odour-cued memories and odour-cued representations of future events regarding their temporal distance to the present. We investigated the temporal distribution and other phenomenological qualities of autobiographical memories and future events employing a 2 (temporal direction: past vs future)×3 (cue type: verbal, visual, and odour) mixed design. We found that while odour-evoked memories were predominantly from the first decade of life, the future condition showed a marked preponderance of odour-cued events in the upcoming year. Odour-evoked memories were also less specific than the verbal and visual conditions. The odour condition was responsible for interactions concerning coherency of the events and the events’ significance to the life story. The results support the view that odours possess a unique ability to evoke remote autobiographical memories.     

Ordering the components of autobiographical events

Memory for the temporal order of the components of autobiographical events was examined in two experiments. Experiments 1 and 2 examined the relationship between reaction times to recognise photographs of the components of events and ordering of these photographs. Reaction times were not related to true event position, nor to assigned temporal position, in a manner consistent with an activation strength model of temporal ordering. In contrast, ordering performance was found to be related to event vividness ratings, ability to classify a photograph as one the participant had taken, and retention interval. These findings are all consistent with the hypothesis that the order of an autobiographical event's components is determined by the associative structure that links each component to its general event memory. Overall, memory for the order of the components of autobiographical events may be initially based on associations between the event components and their general event memory representation. These associations appear to decay rapidly leaving only reconstructive ability as the determinant of event component order.     

Self-events and other-events: Temporal dating and event memory

A diary methodology was used to assess factors related to temporal dating and cued recall of real-world events. In one diary, participants kept a record of unique personal autobiographical events. In a second diary, participants recorded unique events from the life of a friend or relation. At the time each event was recorded, participants rated the event’s pleasantness, person typicality, and degree of initial mental involvement in the event. At the end of the academic quarter, participants provided a recall rating, a rehearsal rating, a date estimate, and a report of the strategy used to estimate the date for each event. Results of regression analyses indicated that both self-events and other-events were characterized by superior memory for person-atypical events. Furthermore, there was a positivity bias in recall for self-events, but there was a negativity bias in recall for other-events. Mediational analyses indicated that the self-event positivity bias was due to enhanced mental involvement when the events occurred, whereas the other-event negativity bias was due to subsequent event rehearsal. The date estimation results indicated that self-event dating was more accurate and evinced less telescoping than other-event dating. Furthermore, the accuracy of date estimates was substantially mediated by event memory. However, mediational differences between self-events and other-events did not emerge. The theoretical implications of these results are discussed.     

Constructing autobiographical events within a spatial or temporal context: a comparison of two targeted episodic induction techniques

ABSTRACT

Recalling and imagining autobiographical experiences involves constructing event representations within spatiotemporal contexts. We tested whether generating autobiographical events within a primarily spatial (where the event occurred) or temporal (the sequence of actions that occurred) context affected how the associated mental representation was constructed. We leveraged the well-validated episodic specificity induction (ESI) technique, known to influence the use of episodic processes on subsequent tasks, to develop variants that selectively enhance spatial or temporal processing. We tested the effects of these inductions on the details used to describe past and future autobiographical events. We first replicated the standard ESI effect, showing that ESI enhances generating episodic details, particularly those that are perception-based, when describing autobiographical events (Experiment 1). We then directly compared the effects of the spatial and temporal inductions (Experiment 2 and 3). When describing autobiographical events, spatial induction enhanced generating episodic details, specifically perception-based details, compared to the control or temporal inductions. A greater proportion of the episodic details generated after the temporal induction were gist-based than after the spatial induction, but this proportion did not differ from a control induction. Thus, using a spatial or temporal framework for autobiographical event generation alters the associated details that are accessed.     

The temporal distribution of past and future autobiographical events across the lifespan

Knowledge and awareness of past and future autobiographical events may be mediated by a common system that supports intentional, goal-directed behavior. The purpose of this study was to assess the correspondence of past and future autobiographical thought. In Experiment 1, 300 undergraduates aged 19 years generated and assigned dates to past and f utu re autobiographical events. Thetemporal distribution of past events replicated a power function for retention as has been described in past research. The intention function of future autobiographical events fit the inverse of this same power function, reflecting a temporality of past and future mental time travel centered around the present moment. In Experiment 2, these findings were extended to young, middle-aged, and older groups. These data provide empirical support for the notion that thinking outside of "now" is mediated by a common system, regardless of whether one is thinking about the past or the future.