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.     

Retrieval-induced forgetting is associated with increased positivity when imagining the future

People often think of themselves and their experiences in a more positive light than is objectively justified. Inhibitory control processes may promote this positivity bias by modulating the accessibility of negative thoughts and episodes from the past, which then limits their influence in the construction of imagined future events. We tested this hypothesis by investigating the correlation between retrieval-induced forgetting and the extent to which individuals imagine positive and negative episodic future events. First, we measured performance on a task requiring participants to imagine personal episodic events (either positive or negative), and then we correlated that measure with retrieval-induced forgetting. As predicted, individuals who exhibited higher levels of retrieval-induced forgetting imagined fewer negative episodic future events than did individuals who exhibited lower levels of retrieval-induced forgetting. This finding provides new insight into the possible role of retrieval-induced forgetting in autobiographical memory.     

When remembering the past suppresses memory for future actions

Remembering planned actions at the correct time in the future is an integral component of prospective cognition. Recent studies on future remembering have led to suggestions that prospective cognition might be based on past experience. To test this hypothesis, we focused on retrieval-induced forgetting (RIF), which usually indicates that remembering past events suppresses memory for related but different past events. The current study assessed RIF in two kinds of event-based prospective memory (PM) tasks using either focal or non-focal cues for ongoing tasks. Participants studied six members from each of eight taxonomic categories and then practiced recalling three of the six members from four of the eight categories using category-stem cues. This retrieval practice suppressed the detection of non-practiced members of the practiced categories during the PM task with non-focal cues (Experiment 1) but not with focal cues (Experiment 2). The results suggest that recall of certain items inhibits the function of the others as PM cues, but only if the PM task does not largely share its processing with the ongoing task.     

Examining the costs and benefits of inhibition in memory retrieval

Inhibitory control is thought to serve an adaptive function in controlling behavior, with individual differences predicting variation in numerous cognitive functions. However, inhibition is more properly construed as inducing both benefits and costs to performance. Benefits arise at the point when inhibition prevents expression of an unwanted or contextually inappropriate response; costs arise later, when access to the inhibited representation is required by other processes. Here we illustrate how failure to consider both the costs and benefits of inhibition has generated confusion in the literature on individual differences in cognitive control. Using retrieval-induced forgetting as a model case, we illustrate this by showing that changing the way that retrieval-induced forgetting is measured to allow greater expression of the benefits of inhibition together with the costs can reduce and even reverse the theoretically predicted correlation between motor and memory inhibition. Specifically, we show that when the final test in a retrieval-induced forgetting procedure employs item-specific cues (i.e., category-plus-stem cued recall and item-recognition) that better isolate the lingering costs of inhibition, better motor response inhibition (faster stop-signal reaction times) predicts greater retrieval-induced forgetting. In striking contrast, when the final test is less well controlled, allowing both the costs and benefits of inhibition to contribute, motor response inhibition has the opposite relationship with retrieval-induced forgetting. These findings underscore the importance of considering the correlated costs and benefits problem when studying individual differences in inhibitory control. More generally, they suggest that a shared inhibition mechanism may underlie people’s ability to control memories and actions.     

Mental time travel into the episodic future,episodic past,and episodic counterfactual past in everyday life

To date, studies exploring the relationship of counterfactual thoughts with episodic memories and episodic future thoughts have focused mainly on voluntary mental time travel. We explore mental time travel in everyday life and find that episodic counterfactual thinking occurs to a much lesser extent than thinking about the past or the future (12%, 22%, and 54%, respectively), is used mainly for mood regulation purposes, and the temporal distribution decreases as a function of time. We observe similarities in phenomenological detail: memories and counterfactual thoughts sharing similar ratings of sensory detail, memories and future thoughts sharing similar ratings of positivity, and counterfactual and future thoughts sharing similar ratings of mental time travel. We discuss the implications of episodic counterfactual thinking in everyday life.     

Recognition memory and awareness: A high-frequency advantage in the accuracy of knowing

The well-established advantage of low-frequency words over high-frequency words in recognition memory has been found to occur in remembering and not knowing. Two experiments employed remember and know judgements, and divided attention to investigate the possibility of an effect of word frequency on know responses given appropriate study conditions. With undivided attention at study, the usual low-frequency advantage in the accuracy of remember responses, but no effect on know responses, was obtained. Under a demanding divided attention task at encoding, a high-frequency advantage in the accuracy of know responses was obtained. The results are discussed in relation to theories of knowing, particularly those incorporating perceptual and conceptual fluency.     

Collective mental time travel: remembering the past and imagining the future together

Synthese - Bringing research on collective memory together with research on episodic future thought, Szpunar and Szpunar (Mem Stud 9(4):376–389, 2016) have recently developed the concept of...     

Minimum presentation time for masked facial expression discrimination

Backward masking is a popular method of preventing awareness of facial expressions, but concerns have been expressed as to the effectiveness of masking in previous research, which may have resulted in unjustified claims of unconscious processing. We examined the minimum presentation time for discrimination of fearful, angry, happy and neutral faces in a backward masking task using both objective sensitivity measures, based on signal detection analysis, and subjective awareness ratings. Results from two experiments showed for all expressions the mean sensitivity and the sensitivity scores of most individual participants were above chance at presentation times of 20 ms. Awareness ratings for happy, fearful and angry also exceeded baseline ratings from 20 ms onwards. Overall sensitivity in both experiments was greatest for happy expressions, which is an agreement with previous reports. The results support the possibility of incomplete masking in earlier studies that used masking to prevent awareness of facial expressions.     

Remembering the past and imagining the future: Differences in event specificity of spontaneously generated thought

A growing interest has emerged in the role that autobiographical memory retrieval plays in simulation of future events. Cognitive explorations in this domain have generally relied on cue word paradigms with instructions to develop specific (relating to one particular day) memories or future events. However, the usefulness of this paradigm has been questioned with respect to its ability to assess habitual patterns of retrieval within autobiographical memory. The current study investigated similarities and differences in how participants spontaneously remember the past and imagine the future when the specificity constraints inherent in the cue word task are removed. A total of 93 undergraduate students completed two sentence-completion tasks, probing for past and future events. A number of differences emerged between past and future thought; in particular, they were less specific when simulating future events compared with past events. This reduction in specificity was the result of participants producing more future thoughts relating to extended lifetime periods and semantic associates. The findings are discussed in relation to the underlying cognitive processes involved in autobiographical memory retrieval and future event simulation.     

Predicting first intercourse among urban early adolescent girls: The role of emotions

Little is known about how girls perceive their ongoing or future sexual experiences, especially the emotions that they associate with these experiences. This study examined how early adolescent girls characterise first intercourse experiences in terms of positive and negative emotions over a one-year period. A US sample of 162 girls (12–14 years), primarily Latina and Black, completed two interviews one year apart that assessed sexual cognitions, affect, and behaviour. Girls anticipated primarily negative emotions associated with first intercourse, but recalled primarily positive emotions for first and recent intercourse experiences. In addition, girls’ emotion scores proved more useful than two types of cognitions (intentions and perceived readiness) and pre-intercourse sexual experience in predicting transitions to intercourse over the one-year period.     

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.     

Narrative self and high risk for schizophrenia: remembering the past and imagining the future

ABSTRACT

We examined the narrative self of those at high psychometric risk for schizophrenia (HR). Eighty undergraduate students wrote personal narratives about a turning-point event in their life, and about a possible future. The turning-point narratives were coded for topic, specificity, event valence, valence of causal coherence link, overall level of causal coherence, and agency. The future narratives were coded for the number and valence of goals, topic of goals, and specificity of goals. Word count was applied to all narratives. The HR group expressed lower levels of agency and a trend of lower levels of causal coherence when narrating turning-point events. When imagining their futures, HR participants produced shorter narratives and showed a trend of having fewer goals. Including the dimensions of both the turning point and the future narratives revealed that the HR group membership was best predicted by lower levels of agency and of causal coherence in the turning-point narrative, and fewer words in the future narrative. Narratives differed specifically in those few elements that are critical for the achievement of narrative continuity. Consistent with the theory, people at high risk for schizophrenia already present, to some extent, an impoverishment in their narrative sense of self.     

Talking about parts of a past experience: The impact of discussion style and event structure on memory for discussed and nondiscussed information

This experiment examined the impact of selective postevent discussion of high- and low-elaborative styles on 5- and 6-year-olds' (N = 47) memory for discussed and nondiscussed aspects of a staged event ("Visiting the Pirate"). The event contained both logically and arbitrarily connected scenes. Discussion was spaced over 3 days, and memory was assessed 1 day later. Compared with a no-discussion condition, memory for discussed information was enhanced after high- but not low-elaborative discussion for both logically and arbitrarily connected scenes. For arbitrarily connected scenes, memory for nondiscussed aspects was impaired relative to the no-discussion condition, with the degree of impairment being equal after high- and low-elaborative discussion. In contrast, for logically connected scenes, memory for nondiscussed information was not impaired after discussion of either style.     

Explaining retrieval-induced forgetting: A change in mental context between the study and restudy practice phases is not sufficient to cause forgetting

Retrieving information can impair the subsequent recall of related information. Such retrieval-induced forgetting is often attributed to inhibitory mechanisms, but Jonker, MacLeod, and Seli (2013) recently proposed an alternative account. In their view, the study and retrieval-practice phases constitute two disparate contexts, and impairment of unpractised members from practised categories is attributable to their being absent from the retrieval-practice context, which is where, according to Jonker et al., participants preferentially search at the time of final test. In evidence of this account, Jonker et al. showed that even restudy practice—which is assumed by the inhibitory account to be insufficient to cause forgetting (i.e., retrieval-specificity)—can cause forgetting when a mental context change is inserted between study and restudy. The present research sought to replicate this finding while also testing the possibility that a far mental context change would cause more forgetting than a near mental context change. In Experiment 1, participants described a vacation inside the United States (near) or outside the United States (far). In Experiments 2 and 3, participants described the layout of their own home (near) or their parents’ home (far). In contrast to the predictions of the context account, however, but consistent with the predictions of the inhibitory account, none of the restudy-plus-context-change conditions resulted in significant forgetting.     

Forgetting motor programmes: Retrieval dynamics in procedural memory

When motor sequences are stored in memory in a categorised manner, selective retrieval of some sequences can induce forgetting of the non-retrieved sequences. We show that such retrieval-induced forgetting (RIF) occurs not only in cued recall but also in a test assessing memory indirectly by providing novel test cues without involving recall of items. Participants learned several sequential finger movements (SFMs), each consisting of the movement of two fingers of either the left or the right hand. Subsequently, they performed retrieval practice on half of the sequences of one hand. A final task then required participants to enter letter dyads. A subset of these dyads corresponded to the previously learned sequences. RIF was present in the response times during the entering of the dyads. The finding of RIF in the slowed-down execution of motor programmes overlapping with initially trained motor sequences suggests that inhibition resolved interference between procedural representations of the acquired motor sequences of one hand during retrieval practice.     

Remembering the past and imagining the future in schizophrenia

It has been suggested that patients with schizophrenia experience a distorted sense of continuity of self across time. However, temporal aspects of self-processing have received little empirical attention in schizophrenia. In this study, the authors investigated schizophrenic patients' ability to generate specific mental images of their personal past and future. Results showed that patients recalled fewer specific past events than did healthy controls and were even more impaired in generating specific future events. These deficits were associated with positive symptoms but were not associated with negative symptoms or with performances on verbal fluency tasks. It is suggested that schizophrenic patients' failures to project themselves into specific past and future episodes might be related to difficulties in retrieving contextual details from memory, as well as disturbance of the sense of subjective time.