Reflections on the spoon test

Is episodic-like memory like episodic memory?

Episodic memory involves the conscious recollection of personally experienced events and when absent, results in profound losses to the typical human conscious experience. Over the last 2.5 decades, the debate surrounding whether episodic memory is unique to humans has seen a lot of controversy and accordingly has received significant research attention. Various behavioural paradigms have been developed to test episodic-like memory; a term designed to reflect the behavioural characteristics of episodic memory in the absence of evidence for consciously experienced recall. In this review, we first outline the most influential paradigms that have been developed to assess episodic-like memory across a variety of non-human taxa (including mammals, birds and cephalopods), namely the what-where-when memory, incidental encoding and unexpected question, and source memory paradigms. Then, we examine whether various key features of human episodic memory are conceptually represented in episodic-like memory across phylogenetically and neurologically diverse taxa, identifying similarities, differences and gaps in the literature. We conclude that the evidence is mixed, and as episodic memory encompasses a variety of cognitive structures and processes, research on episodic-like memory in non-humans should follow this multifaceted approach and assess evidence across various behavioural paradigms that each target different aspects of human episodic memory.This article is part of the theme issue 'Elements of episodic memory: lessons from 40 years of research'.

Beyond the Tricks: The Science and Comparative Cognition of Magic

Magic is an art form that has fascinated humans for centuries. Recently, the techniques used by magicians to make their audience experience the impossible have attracted the attention of psychologists, who, in just a couple of decades, have produced a large amount of research regarding how these effects operate, focusing on the blind spots in perception and roadblocks in cognition that magic techniques exploit. Most recently, this investigation has given a pathway to a new line of research that uses magic effects to explore the cognitive abilities of nonhuman animals. This new branch of the scientific study of magic has already yielded new evidence illustrating the power of magic effects as a psychological tool for nonhuman animals. This review aims to give a thorough overview of the research on both the human and nonhuman perception of magic effects by critically illustrating the most prominent works of both fields of inquiry.

Narrative-based autobiographical memory interventions for PTSD: a meta-analysis of randomized controlled trials

Introduction

The aim of this systematic review and meta-analysis is to evaluate the efficacy of narrative-based interventions (NBIs) for individuals with post-traumatic stress disorder (PTSD). Investigating the efficacy of NBIs should yield insight on autobiographical memory (AM) phenomena implicated in PTSD onset and recovery, leading to improved intervention protocols. Furthermore, by analyzing how NBIs influence maladaptive AM distortions, we hope to shed light on the theorized narrative architecture of AM more generally.

Methods

A systematic literature search was conducted according to PRISMA and Cochrane guidelines in MEDLINE, EMBASE, PsychINFO, and PubMed. Additional studies were then also identified from the reference lists of other relevant literature and considered for inclusion. Studies were then evaluated for adherence to the inclusion/exclusion criteria and assessed for risk of bias. Various meta-analyses were performed on included studies to understand how NBIs may or may not influence the overall effect size of treatment.

Results

The results of the meta-analysis of 35 studies, involving 2,596 participants, suggest that NBIs are a viable and effective treatment option for PTSD, yielding a statistically significant within-group effect size and decrease in PTSD symptomatology at both post-treatment [g = 1.73, 95% CI (1.23-2.22)] and 3-9 month follow-up assessments [g = 2.33, 95% CI (1.41-3.26)]. Furthermore, the difference in effect sizes between NBIs compared to active and waitlist controls was statistically significant, suggesting that NBIs are superior. Sub-analyses showed that NET provided a stronger effect size than FORNET, which may be due to the nature of the traumatic event itself and not the treatment protocol. While evidence of small study and publication bias was present, a weight-function model and trim-and-fill method suggested it was not influencing the overall results.

Discussion

This meta-analysis presents strong evidence supporting the use of NBIs in the treatment of PTSD. Clear similarities can be identified between NBIs included in this analysis that make them distinct from non-NBI interventions, which are reviewed in the discussion. Controlled comparisons between NBIs and non-NBIs would help to further understand AM mechanisms of action implicated in recovery and how various interventions facilitate them. Future research should also aim to elucidate the full range of AM impairment in individuals with PTSD to gain insight on how other memory capabilities, such as the ability to mentally simulate the future, are implicated in the pathogenesis of PTSD.

The Ape That Lived to Tell the Tale. The Evolution of the Art of Storytelling and Its Relationship to Mental Time Travel and Theory of Mind

Engaging in the art of creating and telling stories is a defining behaviour of humankind. Humans have been sharing stories with each other, with and without words, since the dawn of recorded history, but the cognitive foundations of the behaviour can be traced deeper into our past. The emergence of stories can be strongly linked to Mental Time Travel (the ability to recall the past and imagine the future) and plays a key role in our ability to communicate past, present and future scenarios with other individuals, within and beyond our lifetimes. Stories are products engraved within the concept of time, constructed to elucidate the past experiences of the self, but designed with the future in mind, thus imparting lessons of such experiences to the receiver. By being privy to the experiences of others, humans can imagine themselves in a similar position to the protagonist of the story, thus mentally learning from an experience they might have never encountered other than in the mind's eye. Evolutionary Psychology investigates how the engagement in artistic endeavours by our ancestors in the Pleistocene granted them an advantage when confronted with obstacles that challenged their survival or reproductive fitness and questions whether art is an adaptation of the human mind or a spandrel of other cognitive adaptations. However, little attention has been placed on the cognitive abilities that might have been imperative for the development of art. Here, we examine the relationship between art, storytelling, Mental Time Travel and Theory of Mind (i.e., the ability to attribute mental states to others). We suggest that Mental Time Travel played a key role in the development of storytelling because through stories, humans can fundamentally transcend their present condition, by being able to imagine different times, separate realities, and place themselves and others anywhere within the time space continuum. We argue that the development of a Theory of Mind also sparked storytelling practises in humans as a method of diffusing the past experiences of the self to others whilst enabling the receiver to dissociate between the past experiences of others and their own, and to understand them as lessons for a possible future. We propose that when artistic products rely on storytelling in form and function, they ought to be considered separate from other forms of art whose appreciation capitalise on our aesthetic preferences.

Episodic-like memory is preserved with age in cuttlefish

Episodic memory, remembering past experiences based on unique what–where–when components, declines during ageing in humans, as does episodic-like memory in non-human mammals. By contrast, semantic memory, remembering learnt knowledge without recalling unique what–where–when features, remains relatively intact with advancing age. The age-related decline in episodic memory likely stems from the deteriorating function of the hippocampus in the brain. Whether episodic memory can deteriorate with age in species that lack a hippocampus is unknown. Cuttlefish are molluscs that lack a hippocampus. We test both semantic-like and episodic-like memory in sub-adults and aged-adults nearing senescence (n = 6 per cohort). In the semantic-like memory task, cuttlefish had to learn that the location of a food resource was dependent on the time of day. Performance, measured as proportion of correct trials, was comparable across age groups. In the episodic-like memory task, cuttlefish had to solve a foraging task by retrieving what–where–when information about a past event with unique spatio-temporal features. In this task, performance was comparable across age groups; however, aged-adults reached the success criterion (8/10 correct choices in consecutive trials) significantly faster than sub-adults. Contrary to other animals, episodic-like memory is preserved in aged cuttlefish, suggesting that memory deterioration is delayed in this species.

Young children's future-oriented reasoning for self and other: Effects of conflict and perspective

Young children reason more adaptively about the future (e.g., predicting preferences and delaying gratification) when they are asked to think about another person's perspective versus their own perspective. An explanation for this "other-over-self" advantage is that in contexts where current (e.g., small reward now) and future (e.g., larger reward later) desires conflict, adopting the perspective of another person provides psychological distance and hence more adaptive decision making by reducing conflict. We tested this hypothesis in 158 preschoolers using a battery of representative future-oriented reasoning tasks (Preferences, Delay of Gratification, Picture Book, and "Spoon") in which we varied the perspective children adopted (self or other) and the level of conflict between current and future desires (high or low). We predicted that perspective and conflict would interact such that children would benefit most from taking the perspective of "other" when conflict was high. Although results did not support this hypothesis, we found significant effects of conflict; children reasoned more optimally on our low-conflict task condition than on our high-conflict task condition, and these differences did not appear to be related to inhibitory control. The effect of conflict was most marked in younger preschoolers, resulting in Age × Conflict interactions on two of our four tasks. An other-over-self advantage (i.e., perspective effect) was detected on the Preferences task only. These results add to the growing body of literature on children's future thinking by showing the important role of conflict (and its interaction with age) in the accuracy with which children reason about the future.

The role of the pre-commissural fornix in episodic autobiographical memory and simulation

Neuropsychological and functional magnetic resonance imaging evidence suggests that the ability to vividly remember our personal past, and imagine future scenarios, involves two closely connected regions: the hippocampus and ventromedial prefrontal cortex (vmPFC). Despite evidence of a direct anatomical connection from hippocampus to vmPFC, it is unknown whether hippocampal-vmPFC structural connectivity supports both past- and future-oriented episodic thinking. To address this, we applied a novel deterministic tractography protocol to diffusion-weighted magnetic resonance imaging (dMRI) data from a group of healthy young adult humans who undertook an adapted past-future autobiographical interview (portions of this data were published in Hodgetts et al., 2017a). This tractography protocol enabled distinct subdivisions of the fornix, detected previously in axonal tracer studies, to be reconstructed in vivo, namely the pre-commissural (connecting the hippocampus to vmPFC) and post-commissural (linking the hippocampus and medial diencephalon) fornix. As predicted, we found that inter-individual differences in pre-commissural - but not post-commissural - fornix microstructure (fractional anisotropy) were significantly correlated with the episodic richness of both past and future autobiographical narratives. Notably, these results held when controlling for non-episodic narrative content, verbal fluency, and grey matter volumes of the hippocampus and vmPFC. This study provides novel evidence that reconstructing events from one's personal past, and constructing possible future events, involves a distinct, structurally-instantiated hippocampal-vmPFC pathway.