Cognitive approaches to the study of episodic future thinking

The concept of episodic future thinking—the ability to simulate events that may take place in the personal future—has given rise to an exponentially growing field of research that spans a variety of sub-disciplines within psychology and neuroscience. In this introduction to the special issue, we provide a brief historical overview of factors that have shaped research on the topic and highlight the need for additional behavioural work to uncover cognitive mechanisms that support episodic future thinking and differentiate it from other related modes of future-oriented cognition. We conclude by discussing the manner in which the various contributions to the special issue fill the gaps in our knowledge and make some of our own suggestions for future work.     

Understanding the underlying mechanism of the spacing effect in verbal learning: a case for encoding variability and study-phase retrieval

The spacing effect refers to the mnemonic benefit of spacing repeated study events across time compared to massing (i.e. cramming) repeated study events. Due to the robustness of this finding, substantial research has been devoted to uncovering the spacing effect’s underlying mechanism. Specification of such a mechanism has been guided by consistent findings across methodologies and several experimental manipulations that serve as boundary conditions. Past reviews of the spacing effect literature have generally considered subsets of these factors but never an exhaustive set. Thus, the current review considers more comprehensively six consistent findings in the extant spacing effect literature pertaining to human memory to better discriminate among the previously proposed theories. Review of the literature provides substantial evidence indicating the need for an encoding variability mechanism [e.g. Glenberg, A. M. (1976). Monotonic and nonmonotonic lag effects in paired-associate and recognition memory paradigms. Journal of Verbal Learning and Verbal Behavior, 15, 1–16] in addition to a reminding mechanism [e.g. Benjamin, A. S., &; Tullis, J. G. (2010). What makes distributed practice effective? Cognitive Psychology, 61, 228–247].     

The Parallel Episodic Processing (PEP) model 2.0: A single computational model of stimulus-response binding,contingency learning,power curves,and mixing costs

The current paper presents an extension of the Parallel Episodic Processing model. The model is developed for simulating behaviour in performance (i.e., speeded response time) tasks and learns to anticipate both how and when to respond based on retrieval of memories of previous trials. With one fixed parameter set, the model is shown to successfully simulate a wide range of different findings. These include: practice curves in the Stroop paradigm, contingency learning effects, learning acquisition curves, stimulus-response binding effects, mixing costs, and various findings from the attentional control domain. The results demonstrate several important points. First, the same retrieval mechanism parsimoniously explains stimulus-response binding, contingency learning, and practice effects. Second, as performance improves with practice, any effects will shrink with it. Third, a model of simple learning processes is sufficient to explain phenomena that are typically (but perhaps incorrectly) interpreted in terms of higher-order control processes. More generally, we argue that computational models with a fixed parameter set and wider breadth should be preferred over those that are restricted to a narrow set of phenomena.     

No evidence of risk-taking or impulsive behaviour in a person with episodic amnesia: Implications for the role of the hippocampus in future-regarding decision-making

Does advantageous decision-making require one to explicitly remember the outcome of a series of past decisions or to imagine future personal consequences of one's choices? Findings that amnesic people with hippocampal damage cannot form a clear preference for advantageous decks over many learning trials on the Iowa Gambling Task (IGT) have been taken to suggest that complex decision-making on the IGT depends on declarative (episodic) memory and hippocampal integrity. Alternatively, impaired IGT performance in amnesic individuals could be secondary to risk-taking and/or impulsive behaviour resulting from impaired episodic future thinking (i.e. prospection) known to accompany amnesia. We tested this possibility in the amnesic individual K.C. using the IGT and the Toronto Gambling Task (TGT), a novel task that dissociates impulsivity from risk-taking without placing demands on declarative memory. K.C. did not develop a preference for advantageous over disadvantageous decks on the IGT and, instead, showed a slight preference for short-term gains and an inability to acquire a more adaptive appreciation of longer-term losses. He also did not display impulsive or risk-taking behaviour on the TGT, despite a profound inability to imagine personal future experiences. These findings suggest that impaired decision-making on the IGT in amnesia is unlikely to reflect a predilection to act in the moment or failure to take future consequences into account. Instead, some forms of future-regarding decision-making may be dissociable, with performance on tasks relying on declarative learning or on episodic-constructive processes more likely to be impaired.     

Reversible Verbal Memory Integration Deficits in Obstructive Sleep Apnoea

When presented with novel but semantically related elements after learning verbal material, healthy participants tend to endorse these items as previously learned. This reflects the normal integration and association of novel verbal information into long-term memory. How obstructive sleep apnoea (OSA) negatively impacts verbal memory performance, and whether deficits are reversible following positive airway pressure (PAP) treatment, remain elusive. We investigated immediate and delayed OSA- and PAP treatment-related effects on verbal memory integration, using a false memory paradigm. Twenty-three patients with OSA learned lists of words semantically related to target non-presented words (1) at baseline after a polysomnography diagnosis night, (2) after a consecutive polysomnography night under PAP titration, and (3) after three months of compliant PAP treatment. At each session, participants learned 10 different lists of words, each list comprising 15 semantically related items. They had then to recognize 15 minutes later (after an intermediate vigilance task) previously learned words within a list including studied words (learned), unstudied but semantically related items (lures), and non-related unstudied items (controls). Sleep quality and fatigue questionnaires, and psychomotor vigilance tests (PVT) were administered at each session. PAP treatment led to OSA remission and improvement in objective and subjective sleep quality. Crucially, recognition of learned and lure words increased after the first night under treatment and remained stable three months later, suggesting successful memory integration and restoration of semantic processes. No treatment-related outcome was found on PVT performance. OSA exerts a detrimental but PAP-reversible effect on verbal learning and semantic memory integration mechanisms underlying the acquisition of novel memory representations.     

The role of attention at retrieval on the false recognition of negative emotional DRM lists

This study examined the role of attention at retrieval on the false recognition of emotional items using the Deese–Roediger–McDermott (DRM) paradigm. Previous research has shown that divided attention at test increases false remember judgements for neutral critical lures. However, no research has yet directly assessed emotional false memories when attention is manipulated at retrieval. To examine this, participants studied negative (low in valence and high in arousal) and neutral DRM lists and completed recognition tests under conditions of full and divided attention. Results revealed that divided attention at retrieval increased false remember judgements for all critical lures compared to retrieval under full attention, but in both retrieval conditions, false memories were greater for negative compared to neutral stimuli. We believe that this is due to reliance on a more easily accessible (meaning of the word) but less diagnostic form of source monitoring, amplified under conditions of divided attention.     

Discrepancy detection in the retrieval-enhanced suggestibility paradigm

Retrieval-enhanced suggestibility (RES) refers to the finding that immediately recalling the details of a witnessed event can increase susceptibility to later misinformation. In three experiments, we sought to gain a deeper understanding of the role that retrieval plays in the RES paradigm. Consistent with past research, initial testing did increase susceptibility to misinformation – but only for those who failed to detect discrepancies between the original event and the post-event misinformation. In all three experiments, subjects who retrospectively detected discrepancies in the post-event narratives were more resistant to misinformation than those who did not. In Experiments 2 and 3, having subjects concurrently assess the consistency of the misinformation narratives negated the RES effect. Interestingly, in Experiments 2 and 3, subjects who had retrieval practice and detected discrepancies were more likely to endorse misinformation than control subjects who detected discrepancies. These results call attention to limiting conditions of the RES effect and highlight the complex relationship between retrieval practice, discrepancy detection, and misinformation endorsement.     

Retrieval activates related words more than presentation

Retrieving information enhances learning more than restudying. One explanation of this effect is based on the role of mediators (e.g., sand-castle can be mediated by beach). Retrieval is hypothesised to activate mediators more than restudying, but existing tests of this hypothesis have had mixed results [Carpenter, S. K. (2011). Semantic information activated during retrieval contributes to later retention: Support for the mediator effectiveness hypothesis of the testing effect. Journal of Experimental Psychology: Learning, Memory, and Cognition, 37(6), 1547–1552. doi:10.1037/a0024140; Lehman, M., &; Karpicke, J. D. (2016). Elaborative retrieval: Do semantic mediators improve memory? Journal of Experimental Psychology: Learning, Memory, and Cognition, 42(10), 1573–1591. doi:10.1037/xlm0000267]. The present experiments explored an explanation of the conflicting results, testing whether mediator activation during a retrieval attempt depends on the accessibility of the target information. A target was considered less versus more accessible when fewer versus more cues were given during retrieval practice (Experiments 1 and 2), when the target had been studied once versus three times initially (Experiment 3), or when the target could not be recalled versus could be recalled during retrieval practice (Experiments 1–3). A mini meta-analysis of all three experiments revealed a small effect such that retrieval activated mediators more than presentation, but mediator activation was not reliably related to target accessibility. Thus, retrieval may enhance learning by activating mediators, in part, but these results suggest the role of other processes, too.     

How is the visual working memory load of driver influenced by information density of traffic signs?

The rapid development of urban roads has resulted in an increase in the amount of information that needs to be displayed on traffic signs. The overloading of information on traffic signs may increase drivers’ visual cognition burden and cause driving errors. It could be an important factor affecting driving safety and result in accidents. To enable drivers to cognize traffic signs, the information density that they could endure under reasonable workload levels should be determined. In this study, we designed and implemented trials to analyze drivers’ visual working memory load (VWML) caused by different information densities (including stimulus intensity (SI) and interval time of stimulus (IS)) of traffic signs. Twenty-four paid participants (12 females) with a mean age of 23.38 years (SD = 1.38) participated in laboratory simulation trials based on the memory retrieval approach. Subjective ratings (rating scale mental effort (RSME)), and performance measurement based on reaction time and accuracy of information-matching task were measured to reflect drivers’ VWML at different information densities. The results show that information density is an important factor affecting drivers’ VWML. The following are the significant observations of the study: (1) The subjective ratings on mental effort increased with increase in the SI. Meanwhile, it first decreased and then increased with increase in the IS. (2) The response accuracy results show that a high accuracy (≥0.7) was achieved by drivers in an IS of 15 s when the SI was at most 14.16 bit/m². Correspondingly, the drivers underwent less mental workload as a result of their better short-term memory characteristic. (3) The mean reaction time was over 1800 ms when the SI was over 14.16 bit/m². This indicated a reduction in the information-processing capability of the drivers. The results indicate that cognition of information of unreasonable density on traffic signs would increase drivers’ VWML. This would, in turn, result in an increase in their reaction time and decrease in accuracy. The threshold of information density was also determined through the experiment. It would satisfy the information demand of drivers and prevent information redundancy. The results contribute to an understanding of drivers’ VWML while cognizing traffic signs with different information densities and provide safety, effectiveness, and information continuity considerations for the design and setting of traffic signs.