Why are we not flooded by involuntary thoughts about the past and future? Testing the cognitive inhibition dependency hypothesis

Dataset of autobiographical and future-related thoughts recorded during a laboratory vigilance task with working memory load manipulation

The dataset provided in this article comprises frequencies of task-related thoughts, task-unrelated thoughts, involuntary autobiographical memories (IAMs), and involuntary future thoughts (IFTs) reported by adult participants during a laboratory vigilance task. Participants completed a vigilance task that included incidental cue words intended to trigger IAMs and IFTs, whose frequency was measured using random thought probes. The data were collected from two studies (n = 240 per study) in which working memory load and cue-presentation were manipulated. In both studies, participants completed an unexpected cue-recognition task after completing the vigilance task, which allowed for gathering additional data about noticing and remembering specific categories of cues (positive, neutral or negative). The dataset includes not only the frequencies of specific categories of thoughts but also data from numerous follow-up questions related to how participants perceived their performance in the task, such as their concentration level or perceived task difficulty. In conclusion the dataset contains three categories of variables: (1) variables related to participants and the conditions of the experimental sessions (i.e., age, gender, working memory load condition, etc.); (2) variables related to control questions (i.e., perceived task difficulty, emotional states, fatigue, etc.); and (3) variables related to performance in the vigilance task and the occurrence of thoughts (i.e., number of task-unrelated thoughts, number of involuntary memories, percentage of successfully recognized cues, etc.). This dataset could be reused to investigate many interesting relationships between cognitively engaging computer task characteristics and various parameters of task performance. Additionally, it could be used to conduct alternative or replication analyses to gain a deeper understanding of the relationship between working memory load and the experience of involuntary thoughts.

On second thoughts: Testing the underlying mechanisms of spontaneous future thought

The human capacity to imagine possible future events unintentionally, with minimal cognitive effort, is termed spontaneous future thought (SFT). This paper addresses an important theoretical question for cognitive science: What are the possible cognitive mechanisms underlying such SFT experiences? We contrasted three hypotheses present in the literature: the online construction hypothesis, the recasting hypothesis, and the memories of future thoughts hypothesis. Study 1 (N = 41) used novel subjective ratings which challenged the recasting mechanism: SFTs were mostly rated as dissimilar to autobiographical memories, suggesting they are not simply past experiences 'recast' as future events. Study 2 (N = 90) used a novel experimental paradigm, comparing effects of voluntary episodic future constructions and non-personal narratives upon subsequent spontaneous thought sampling. Results suggested that voluntary future constructions remain accessible to spontaneous retrieval, supporting the memories of future thoughts hypothesis. This finding, and other data presented across the two studies, still indicates a role for online construction processes in SFT, but further empirical work is needed to clarify how and when constructive processes are engaged in SFT. Taken together, these two studies represent initial efforts to elucidate the mechanisms underlying SFT, providing the first proof-of-principle that deliberately envisioned future events can reappear, without intention, in consciousness at some later time, and further supporting the dual process account of future thinking. These methods and findings provide a firm basis for subsequent experimental and longitudinal research on SFT.

Semantic-to-autobiographical memory priming: the role of cue repetition

It is now well established that general information processing causes the activation of memories in the autobiographical memory system, and these memories on occasion emerge as involuntary autobiographical memories. This priming phenomenon has been dubbed semantic-to-autobiographical memory priming, and our goal in the current study was to examine the effects of cue/prime repetition on the production of involuntary autobiographical memories that were primed with semantic stimuli. In three experiments, participants were primed with words (e.g., cat), and then they were given an involuntary memory task (the vigilance task), which contained cues related to the primed stimuli. In Experiment 1, the cues were phrases containing the primes (e.g., getting a cat), which were presented one or five times. In Experiment 2, the cues were also phrases containing the primes (e.g., getting a cat), but they changed their context (e.g., feeding a cat), every time they repeated in the five-presentation condition. Experiment 3 also presented the cues one or five times, but the cues were replicas of the primes (e.g., cat). Consistent with predictions, greater priming was found in the five-presentation cue conditions in all three experiments, and Experiment 3 failed to find priming in the one-presentation cue condition, also consistent with predictions. We explain the findings in terms of semantic-to-autobiographical memory priming theory, and also argue that the results help explain the production of involuntary memories in everyday life.

Obtaining semantic-to-autobiographical memory priming on the vigilance task with non-verbal cues

Recent research has shown that the activation of semantic memories leads to the activation of autobiographical memories. Known as semantic-to-autobiographical memory priming, this form of priming has been demonstrated to prime involuntary and voluntary autobiographical memories with a wide variety of different primes (i.e., various verbal and non-verbal stimuli). However, only verbal cues have been used in the memory measures, leaving open the question of how non-verbal cues might function. Our goal in the current study was to show that non-verbal cues are also involved in semantic-to-autobiographical memory priming. Participants were primed with words, and then they were treated to an involuntary autobiographical memory task (the vigilance task) where they received either word cues or pictorial cues. The results showed that both the word cues and the pictorial cues had captured primed involuntary memories on the vigilance task relative to controls. The results support the idea that semantic-to-autobiographical memory primes occur with both verbal and non-verbal cues, potentially indicating substantial cue diversity. The results also further support the idea that semantic-to-autobiographical memory priming may play an important role in the production of involuntary autobiographical memories in everyday life.

Priming in the autobiographical memory system: implications and future directions

Studies examining priming in autobiographical memory are fewer in number (some two dozen) compared to other areas (e.g., semantic memory priming), which have seen hundreds of studies. Nevertheless, autobiographical memory priming studies have utilised quite a number of different experimental paradigms, with many having interesting ecological implications. This paper reviews the bulk of these studies. It discusses the various theoretical implications of these studies, past and present. It suggests numerous future directions in this area, as the study of priming in autobiographical memory has had significant implications, despite the small number of studies, and it offers enormous future potential.

Recurrent involuntary memories and mind wandering are related but distinct

Spontaneous thought is common in daily life, and includes recurrent involuntary autobiographical memories (IAMs; memories retrieved unintentionally and repetitively) and mind wandering (MW). Both recurrent IAMs and MW are often unintentional or unconstrained, and both predict symptoms of mental health disorders. However, not all MW is unintentional, and not all IAMs are unconstrained. To what extent do recurrent IAMs and MW converge versus diverge? Undergraduates (N = 2,701) completed self-report measures of recurrent IAMs, trait MW, and psychopathology (i.e., PTSD, depression, anxiety). Regressions indicated that recurrent IAMs were significantly associated with spontaneous MW, but not deliberate MW. Further, both spontaneous MW and recurrent IAMs had unique relationships with disorder symptoms. Results suggest that recurrent IAMs are related to MW to the extent that recurrent IAMs are spontaneous. Conversely, recurrent IAMs are distinct from MW to the extent that recurrent IAMs' associations with disorder symptoms could not be solely explained by trait MW (and vice versa). This work highlights related, but distinguishable, forms of spontaneous thought and their transdiagnostic links with psychopathology.

A comprehensive guide to research protocols for collecting and coding involuntary past and future thoughts

The paper presents a comprehensive guide for researchers investigating mind-wandering and related phenomena such as involuntary past and future thinking. Examining such spontaneous cognitions presents a challenge requiring not only the use of appropriate laboratory-based procedures, but also the coding of complex qualitative data. This guide outlines two main stages of existing research protocols: data acquisition and data coding. For the former, we introduce an easily modifiable computerized version of the vigilance task, designed for broad application in studies focusing on eliciting and measuring involuntary thoughts in controlled laboratory conditions. Regarding data preparation and coding, we provide a detailed step-by-step procedure for categorizing and coding different types of thoughts, involving both participants and competent judges. Additionally, we address some of the difficulties that may arise during this categorization and coding process. The guide is supplemented by a clip demonstrating the main part of the experimental procedure and a step-by-step example of the subsequent data processing stages. We anticipate that this research guide will not only assist a broader group of researchers interested in investigating spontaneous cognition, but will also inspire future studies on spontaneous cognition and related phenomena.•There is a need for standardized approaches to working with qualitative data when investigating spontaneous thoughts.•The paper outlines a comprehensive protocol for collecting and coding involuntary past and future-oriented thoughts.•The paper also presents a detailed step-by-step procedure for data preparation and coding to categorize different types of thoughts, involving both participants and competent judges.

A dual process model of spontaneous conscious thought

In the present article, I review theory and evidence on the psychological mechanisms of mind wandering, paying special attention to its relation with executive control. I then suggest applying a dual-process framework (i.e., automatic vs. controlled processing) to mind wandering and goal-directed thought. I present theoretical arguments and empirical evidence in favor of the view that mind wandering is based on automatic processing, also considering its relation to the concept of working memory. After that, I outline three scenarios for an interplay between mind wandering and goal-directed thought during task performance (parallel automatic processing, off-task thought substituting on-task thought, and non-disruptive mind wandering during controlled processing) and address the ways in which the mind-wandering and focused-attention spells can terminate. Throughout the article, I formulate empirical predictions. In conclusion, I discuss how automatic and controlled processing may be balanced in human conscious cognition.

Recovered memories of trauma as a special (or not so special) form of involuntary autobiographical memories

Recovered memories of trauma are memories of traumatic events experienced generally during childhood, but of which the persons were unaware until they retrieved it. Legal decisions are sometimes based on such recovered memories, the validity of which is often questioned. Yet, people can recover genuine traumatic memories of childhood abuse. In this paper, we present and further discuss the idea that recovered traumatic memories can be interpreted in the context of the autobiographical memory framework. Specifically, we argue that recovered memories may be accessed after exposure to incidental cues that initiate unexpected spontaneous memory retrieval. Thus, we relate the recovered memory phenomenon to involuntary autobiographical memories and argue that it is an example of highly stressful, emotionally negative, and intense involuntary memories that were yet never recalled. This novel, evidence-based perspective leads us to reconsider the examination of the validity of eyewitness testimony as a continuum ranging from the least valid form (i.e., memories recovered in highly suggestive context facilitating its factitious reconstruction) to the most valid form (i.e., memories that were triggered by cues without any person's voluntary engagement), and this in relation with how internal (e.g., age and internal cue) or external (e.g., suggestion in therapy, suggestion during investigative interview, and contextual cue) factors may influence memory retrieval. Finally, we propose several recommendations for experts that may be useful in assessing the validity of a testimony based on recovered memories.

Does inhibitory (dys)function account for involuntary autobiographical memory and déjà vu experience?

External cues and internal configuration states are the likely instigators of involuntary autobiographical memories (IAMs) and déjà vu experience. Indeed, Barzykowski and Moulin discuss relevant neuroscientific evidence in this direction. A complementary line of enquiry and evidence is the study of inhibition and its role in memory retrieval, and particularly how its (dys)function may contribute to IAMs and déjà vu.

Semantic-to-autobiographical memory priming is ubiquitous

It is now well established that the activation of semantic memories leads to the activation of autobiographical memories. Studies have shown that semantic processing of words or pictures primes autobiographical memories on voluntary and involuntary autobiographical memory tasks (the Crovitz cue-word task and the vigilance task). Known as semantic-to-autobiographical memory priming, our goal in the current study was to demonstrate the ubiquitous nature of this form of priming by showing that a wide variety of stimuli will prime involuntary autobiographical memories on the vigilance task. In Experiment 1, semantic-to-autobiographical priming was obtained on the vigilance task following the processing of sounds (e.g., the sound of bowling) and spoken words (e.g., the word bowling). In Experiment 2, semantic-to-autobiographical priming was observed on the vigilance task following tactile processing (e.g., the objects ball, glasses) and visual word processing (e.g., the words ball, glasses). In Experiment 3, semantic-to-autobiographical priming was observed on the vigilance task following the processing of videos (e.g., videos of a marching parade) and visual word processing (e.g., the word parade). The results of these experiments support the idea that semantic-to-autobiographical activations occur across a wide variety of stimuli (e.g., linguistic, perceptual). The results also further support the idea that semantic-to-autobiographical memory priming may play an important role in the production of involuntary memories in everyday life. Additional implications (for priming theory and autobiographical memory functions) are discussed.

Intention and Monitoring Influence the Content of Memory Reports

OBJECTIVES

While voluntary memories are intended and expected, involuntary memories are retrieved with no intention and are usually unexpected (when one is not waiting for a memory). The present study investigates the effects of retrieval intentionality (wanting to retrieve a memory) and monitoring processes (expecting a memory to appear) on the characteristics of autobiographical memories.

METHODS

To this end, by applying mixed-method analysis of memory descriptions (i.e. combining qualitative with quantitative analyses) we re-analysed the large pool of involuntary and voluntary memories obtained in one previously published study, asking independent judges to rate all the memories on several dimensions reflecting memory accessibility (i.e. the likelihood that a memory can be retrieved).

RESULTS

When discussing our findings, we speculate that there may be several stages of memory retrieval that might be differently influenced by intention and monitoring.

CONCLUSIONS

We discuss the novel hypothesis that there may be two different types of monitoring that operate independently of each other, before and after retrieval, respectively.

Are involuntary autobiographical memory and déjà vu natural products of memory retrieval?

Involuntary autobiographical memories (IAMs) and déjà vu are phenomena that occur spontaneously in daily life. IAMs are recollections of the personal past, whereas déjà vu is defined as an experience in which the person feels familiarity at the same time as knowing that the familiarity is false. We present and discuss the idea that both IAMs and déjà vu can be explained as natural phenomena resulting from memory processing and, importantly, are both based on the same memory retrieval processes. Briefly, we hypothesise that both can be described as "involuntary" or spontaneous cognitions, where IAMs deliver content and déjà vu delivers only the feeling of retrieval. We map out the similarities and differences between the two, making a theoretical and neuroscientific account for their integration into models of memory retrieval and how the autobiographical memory literature can explain these quirks of daily life and unusual but meaningful phenomena. We explain the emergence of the déjà vu phenomenon by relating it to well-known mechanisms of autobiographical memory retrieval, concluding that IAMs and déjà vu lie on a continuum.

Semantic-to-autobiographical memory priming affects involuntary autobiographical memory production after a long delay

It has recently been demonstrated that the activation of semantic memories primes involuntary autobiographical memories on a laboratory measure of involuntary memories (i.e., the vigilance task), suggesting that this form of priming (known as semantic-to-autobiographical) plays a role in the production of involuntary autobiographical memories in everyday life. Our goal in the current study was to replicate those priming effects, and show that they can have long durations. In a single experiment, semantic-to-autobiographical memory priming was obtained on the vigilance task following delays of several minutes and seven days. We argue that the results support the idea that semantic-to-autobiographical memory priming plays a role in the production of involuntary memories in everyday life. The full implications of delayed semantic-to-autobiographical priming are discussed.

Effects of inhibitory control capacity and cognitive load on involuntary past and future thoughts: A laboratory study

The present study focused on involuntary thoughts about personal past events (i.e., involuntary autobiographical memories; IAMs), and involuntary thoughts about future events and plans (i.e., involuntary future thoughts; IFTs). The frequency of these involuntary thoughts is influenced by cognitive demands of ongoing activities, but the exact underlying mechanism(s) has yet to be revealed. The present study tested two possible explanations: (1) the special inhibitory mechanism switches on when one is engaged in attentionally demanding activities; (2) different levels of cognitive load interfere with cue-noticing that act as triggers for IAMs and IFTs. We report a study with pre-selected groups of participants that differed in terms of their individual level of inhibitory control capacity (high vs. low), and completed both standard and attentionally demanding versions of a laboratory vigilance task with irrelevant cue-words to trigger IAMs and IFTs, and random thought-probes to measure their frequency. To examine the level of incidental cue-noticing, participants also completed an unexpected cue-recognition task. Despite large differences between groups in inhibitory control capacity, the number of IFTs and IAMs, reported in the attentionally demanding condition, was comparable. In addition, high cognitive load reduced the number of IAMs, but not IFTs. Finally, the recognition of incidental cues encountered in the vigilance task was reduced under high cognitive load condition, indicating that poor cue-noticing may be the main underlying mechanism of cognitive load effect rather than the lack of inhibitory resources needed to suppress involuntary retrieval. This and other possible mechanisms and avenues for future research are discussed.

The role of inhibitory control and ADHD symptoms in the occurrence of involuntary thoughts about the past and future: An individual differences study

In everyday life, people often experience involuntary thoughts about their personal past and future events in response to incidental cues in the environment. Yet, despite the abundance of such cues, our consciousness is not constantly flooded by these involuntary autobiographical memories (IAMs) and involuntary future thoughts (IFTs). The main goal of the present study was to further investigate the possibility that cognitive inhibitory control keeps these involuntary cognitions at bay. To test this inhibition hypothesis, we conducted a large-scale study (n = 157) in which groups of participants with different levels of inhibitory control (low, medium, high) and individuals with ADHD spectrum symptoms were engaged in a laboratory vigilance task in which the frequency of IFTs and IAMs was assessed. Contrary to predictions, although participants across groups differed significantly in terms of their individual inhibitory control capacity, the number of IFTs and IAMs reported during the vigilance task was comparable. In addition, individuals with the ADHD spectrum symptoms did not report more spontaneous thoughts compared to other groups. Together, these findings lend little support for the idea that inhibition is a key mechanism that regulates the occurrence of IAMs and IFTs in everyday life. Other possible mechanisms and avenues for future research are discussed.

An Inquisit-web protocol for calculating composite inhibitory control capacity score: An individual differences approach

In the present paper, we provide a protocol for experimentally measuring and calculating individual inhibitory control capacity index in adult participants in an online Inquisit-based setting. We believe that this method can serve other researchers in the standardized assessment of individual inhibitory control capacity that can be used in studies on the possible role of inhibitory control in many every-day cognitive phenomena. Thus, the paper focuses mainly on the calculation of a composite inhibitory control capacity score from two inhibitory control tasks. Specifically, it is calculated on the basis of participants' performance in two well-established experimental paradigms: the Stroop Task and the Eriksen Flanker Task. The methods described in this protocol have already been successfully applied in both lab and online settings. In the first part of the article, we provide a short theoretical background and a brief description of the previous usage of this method in our two original studies. In the following parts, we provide step-by-step instructions for measuring and calculating the individual inhibitory control capacity index using web-based methodology. The protocol is supplemented with slides of original experimental tasks and instructions for participants (both translated from Polish).

Episodic-semantic interactions in spontaneous thought

The distinction between a semantic memory system, encompassing conceptual knowledge, and an episodic memory system, characterized by specific episodes, is one of the most important theoretical proposals in cognitive science. However, the distinction between systems has rarely been discussed in relation to spontaneous thought that comes to mind with reduced cognitive effort and intentionality. In this review, we propose that the growing research on spontaneous thought can contribute to current discussions on the interaction between the episodic and semantic systems. Firstly, we review research that shows that, as in deliberate retrieval, spontaneous thoughts are influenced by both episodic and semantic memory, as reflected by the mix of semantic and episodic elements in descriptions of spontaneous thoughts, as well as semantic priming effects in spontaneous thoughts. We integrate the current evidence based on the interplay between cues and semantic activation. Namely, we suggest that cues are key to access episodic memory and modulate the frequency of spontaneous thought, while semantic activation modulates the content of spontaneous thought. Secondly, we propose that spontaneous retrieval is a privileged area to explore the question of functional independence between systems, because it provides direct access to the episodic system. We review the evidence for spontaneous thought in semantic dementia, which suggests that episodic and semantic systems are functionally independent. We acknowledge the scarcity of evidence and suggest that future studies examine the contents of spontaneous thought descriptions and their neural correlates to test the functional relationship and inform the interaction between episodic and semantic systems.

Retrieval effort or intention: Which is more important for participants' classification of involuntary and voluntary memories?

Theories of autobiographical memory distinguish between involuntary and voluntary memories. While involuntary memories are retrieved with no conscious intention and are therefore unexpected, voluntary memories are both intended and expected. Recent research has shown that participants sometimes classify their memories as either involuntary or voluntary based on retrieval effort instead of intention. These findings question whether intention really is the defining difference between these two types of retrieval or whether retrieval effort is also an important determinant. In two experimental studies, we investigated the extent to which participants rely on retrieval effort while classifying their memories as involuntary or voluntary. We created experimental conditions that maximize the probability of one type of retrieval while minimizing the probability of another type. Participants reported autobiographical memories in each condition while the programme registered their retrieval time. They then classified their memories as either voluntary or involuntary and rated all memories on perceived retrieval effort. This gave us four categories of memories: experimentally defined voluntary and involuntary memories with an objective measure of effort (retrieval time) and subjectively classified involuntary and voluntary memories with a subjective measure of effort. This allowed us to investigate the relative contribution of intention and effort to involuntary and voluntary memories. We replicated and extended previous findings by showing that the majority of memories were classified as involuntary independently of whether they were retrieved in the experimentally defined voluntary or involuntary condition. This could indicate that subjective effort is more important than intention for the involuntary-voluntary distinction in contrast with existing theories. We discuss theoretical and methodological implications of this finding.

Spontaneous and deliberate future thinking: a dual process account

In this article, we address an apparent paradox in the literature on mental time travel and mind-wandering: How is it possible that future thinking is both constructive, yet often experienced as occurring spontaneously? We identify and describe two 'routes' whereby episodic future thoughts are brought to consciousness, with each of the 'routes' being associated with separable cognitive processes and functions. Voluntary future thinking relies on controlled, deliberate and slow cognitive processing. The other, termed involuntary or spontaneous future thinking, relies on automatic processes that allows 'fully-fledged' episodic future thoughts to freely come to mind, often triggered by internal or external cues. To unravel the paradox, we propose that the majority of spontaneous future thoughts are 'pre-made' (i.e., each spontaneous future thought is a re-iteration of a previously constructed future event), and therefore based on simple, well-understood, memory processes. We also propose that the pre-made hypothesis explains why spontaneous future thoughts occur rapidly, are similar to involuntary memories, and predominantly about upcoming tasks and goals. We also raise the possibility that spontaneous future thinking is the default mode of imagining the future. This dual process approach complements and extends standard theoretical approaches that emphasise constructive simulation, and outlines novel opportunities for researchers examining voluntary and spontaneous forms of future thinking.

Do intuitive ideas of the qualities that should characterize involuntary and voluntary memories affect their classification?

It is assumed that the difference between voluntary and involuntary autobiographical memories lies in the intentionality to retrieve a memory assigned by the experimenter. Memories that are retrieved when people are instructed to do so in response to cues are considered voluntary (VAMs), those that pop up spontaneously are considered involuntary (IAMs). VAMs and IAMs so classified are also found to differ in terms of phenomenological characteristics, such as perceived accessibility, vividness etc. These differences are assumed to be due to differences in intentionality and the different retrieval processes at play. It is possible, however, that these differences (which are subjective attributions of phenomenological characteristics) are the result of metacognitive beliefs of what IAMs and VAMs should be. In two experiments, we investigated the possible role of these metacognitive beliefs. Participants rated IAMs and VAMs on a number of phenomenological characteristics in two conditions, when these memories were presented in blocks that specified whether they were retrieved in a voluntary or involuntary task, or when presented in a mixed list with no information provided. If metacognitive beliefs influence the reporting of memory properties, then the block presentation would increase the differences between the characteristics of the two types of memories. The results showed that, besides replicating the characteristics of IAMs and VAMs already observed in the literature, there were almost no differences between the blocked and the mixed lists. We discuss the results as supporting the idea that the difference in characteristics attributed to IAMs and VAMs reflect a genuine difference in the nature of the retrieval and is not the result of pre-existing metacognitive belief on what a voluntary and an involuntary memory should be.

Priming autobiographical memories: How recalling the past may affect everyday forms of autobiographical remembering

This study investigated the idea that when one recalls past episodes, that the content of those memories will activate additional episodic memories with like content, and such memories will then have the potential of surfacing in subsequent acts of involuntary and voluntary recall. We tested the episodic content priming hypothesis in two experiments. In Experiment 1, priming group participants first recalled memories about specific activities or events and then they were subsequently engaged in a word-cue voluntary autobiographical memory task. The results showed that priming group participants produced more episodic memories involving the primed content on this task than control participants occupied in the same task. In Experiment 2, episodic content priming was further tested on a measure of involuntary autobiographical memory (i.e., the vigilance task). The results on this task also revealed support for the episodic content priming hypothesis, including after a delay of 24 h.

Predictors of involuntary and voluntary emotional episodic memories of virtual reality scenarios in Veterans with and without PTSD

This study investigated predictors of involuntary and voluntary memories of stressful virtual reality scenarios. Thirty-two veterans of the two Persian Gulf Wars completed verbal memory tests and diagnostic assessments. They were randomly assigned to a Recounting (16) or a Suppression (16) condition. After immersion in the VR scenarios, the Recounting group described the scenarios and the Suppression group suppressed thoughts of the scenarios. One week later, participants completed surprise voluntary memory tests and another thought suppression task. The best predictors of voluntary memory were verbal memory ability, dissociation, and to a lesser extent, physiological arousal before and after scenarios. Dissociation and physiological stress responses selectively affected memory for neutral elements. Higher distress during scenarios impaired voluntary memory but increased the frequency of involuntary memories. Physiological stress responses promoted more frequent involuntary memories immediately after the scenarios. More frequent initial involuntary memories, tonic physiological arousal, and stronger emotional responses to dangerous events predicted difficulty inhibiting involuntary memories at follow-up. The effects of thought suppression were transient and weaker than those of other variables. The findings suggest that posttraumatic amnesia and involuntary memories of adverse events are more related to memory ability and emotional and physiological stress responses than to post-exposure suppression.

A closer look at the timecourse of mind wandering: Pupillary responses and behaviour

Mind wandering (MW) refers to the shift of attention away from a primary task and/or external environment towards thoughts unrelated to the task. Recent evidence has shown that pupillometry can be used as an objective marker of the onset and maintenance of externally-driven MW episodes. In the present study we aimed to further investigate pupillary changes associated with the onset and duration of self-reported MW episodes. We used a modified version of the joint behavioural-pupillometry paradigm we recently introduced. Participants were asked to perform a monotonous vigilance task which was intermixed with task-irrelevant cue-phrases (visually presented verbal cues); they were instructed to interrupt the task whenever a thought came to mind (self-caught method) and to indicate the trigger of their thought, if any. We found systematic pupil dilation after the presentation of verbal cues reported to have triggered MW, compared with other verbal cues presented during a supposedly on-task period (i.e., the period immediately following the resuming of the task after a self-caught interruption and MW report). These results confirm that pupil diameter is sensitive to the changes associated with the onset of MW and its unfolding over time. Moreover, by computing the latency between the trigger presentation and the task interruption (self-catch), we could also estimate the duration of MW episodes triggered by verbal cues. However, a high variability was found, implying very large inter-event variability, which could not be explained by any of the MW properties we acquired (including: temporal focus, specificity, emotional valence). Our behavioural and pupillometry findings stress the need for objective measures about the temporal unfolding of MW (while most studies focus on arbitrary time-window preceding self-reports of MW).

Functions of spontaneous and voluntary future thinking: evidence from subjective ratings

Future thinking is defined as the ability to withdraw from reality and mentally project oneself into the future. The primary aim of the present study was to examine whether functions of future thoughts differed depending on their mode of elicitation (spontaneous or voluntary) and an attribute of goal-relatedness (selected-goal-related or selected-goal-unrelated). After producing spontaneous and voluntary future thoughts in a laboratory paradigm, participants provided ratings on four proposed functions of future thinking (self, directive, social, and emotional regulation). Findings showed that spontaneous and voluntary future thoughts were rated similarly on all functions except the directive function, which was particularly relevant to spontaneous future thoughts. Future thoughts classed as goal-related (selected-goal-related) were rated higher across all functions, and there was largely no interaction between mode of elicitation and goal-relatedness. A higher proportion of spontaneous future thoughts were selected-goal-related compared with voluntary future thoughts. In general, these results indicate that future thinking has significant roles across affective, behavioural, self and social functions, and supports theoretical views that implicate spontaneous future thought in goal-directed cognition and behaviour.

Spontaneous future cognition: the past, present and future of an emerging topic

In this Editorial, we discuss the past, present and future of an emerging and fast-developing field-spontaneous future cognition. In tracking the past of this research, the trajectories of research on mind-wandering, episodic future thinking and prospective memory are briefly examined, and their relation with spontaneous future cognition demarcated. Three broad methodological approaches (questionnaire, naturalistic and laboratory) used to study spontaneous future thoughts are described, providing an overview of the field. The present state of this research is represented by a themed analysis of the articles included in this Special Issue. The breadth of studies (covering cognitive mechanisms, developmental stages and psychopathology) have already led to important insights, especially concerning the conditions in which spontaneous future thoughts most commonly arise and who may be predisposed to experiencing them. In the future, greater effort should focus on developing a theoretical account of spontaneous future cognition-this may increase our understanding of how and why spontaneous future thoughts occur. If future research in this area reflects the diversity and depth within this Special Issue, a flourishing of research on spontaneous future cognition will be on the horizon in years or perhaps decades to come.

How intention to retrieve a memory and expectation that a memory will come to mind influence the retrieval of autobiographical memories

While involuntary memories are retrieved with no intention and are usually unexpected (when one is not waiting for a memory to arise), voluntary memories are intended and expected (when one is searching and waiting for a memory to arise). The present study aimed to investigate the effects of retrieval intentionality (i.e. wanting to retrieve a memory) and monitoring processes (i.e. waiting for a memory to appear) during autobiographical memory retrieval. In addition, we introduced two novel laboratory conditions that have not been used in previous research on voluntary memories: in the first, participants were asked to report anything they could think of in response to each cue word; in the second, they could skip a word if nothing came to mind. These novel manipulations allowed us to differentiate between voluntary memories retrieved in response to experimenter-generated cues (when participants were forced to provide a memory or a thought for each cue) and self-selected cues (when participants were free to not answer a cue if they found it too difficult). We found that highly accessible memories were mostly experienced when retrieval was involuntary and unexpected, while memories with low accessibility were accessed through intentional retrieval and monitoring processes. Response times for memories recalled in the experimenter-generated cue conditions were longer compared to the self-selected cue conditions. This novel finding shows that experimenter-generated recall favours memories with low accessibility; it further supports the idea that, in a substantial number of trials, voluntary memories are directly rather than effortfully retrieved. The idea that the driving force behind differences between involuntary and voluntary memories is not the intention per se is further discussed.

Testing the ego-depletion effect in optimized conditions

The observation that exerting self-control in an initial task impairs subsequent self-control performance in a following task has been used to explain a wide range of phenomena. If evidence for this "ego-depletion" effect was initially believed to be strong, it is now questioned. Recent meta-analyses indicated that this effect was sensitive to publication bias and that it was greatly reduced after control for this bias. In a pre-registered replication attempt where an ego-depletion protocol was conducted in multiple independent laboratories, the effect was not distinguishable from zero. Here, a different approach is adopted to examine the validity of this effect by improving the experimental protocol with the addition of important methodological precautions: 1) a pre-test measurement, 2) a learning period, 3) a prolonged depleting task, 4) a similar control condition, and 5) valid indexes of self-control. Accordingly, a well-learned Simon task was done before and after 1h of continuous practice of a Stroop task in a high inhibition demands condition (75% of incongruent trials) or in a control condition (0% of incongruent trials). Datasets from between-subjects (Study 1, N = 82) and within-subjects (Study 2, N = 52) experiments were analyzed using generalized linear mixed models. A significant ego-depletion effect was found in Study 1 (greater interference effect and accuracy decline in high inhibition demands than in control condition) but not in Study 2. Because it is difficult to explain this difference in results, the findings suggest that, even in a context chosen to optimize the observation of an ego-depletion effect, it seems difficult to be conclusive about the existence of this effect.