Positive and negative touch differentially modulate metacognitive memory judgements for emotional stimuli.

Touch plays a crucial role in providing humans with information from the external environment and can be perceived by humans as positively or negatively valenced. It is well documented that touch can differentially influence social functions, but very little is known about how touch can modulate (meta)cognition. Utilizing a within-subject design, participants were exposed to (a) positive, (b) negative, and (c) no touch, alongside encoding of emotionally valenced (positive and negative) images. After a 20-minute delay, participants completed a Yes/No recognition task to investigate how touch influenced memory-related decision components (e.g. criterion, confidence). Results showed that, compared to the control condition, both positive and negative touch were associated with overall lower confidence ratings, a less liberal response bias and slower response times. Interestingly, for correct recognitions, only negative touch (vs. no touch) led to inappropriately lower confidence and slower response times while both confidence and response time remained unaltered in positive touch. Our findings provide the first evidence that positive and negative touch differentially interact with metacognitive memory-related decisions. Altered metacognitive judgements after being touched could have significant consequences in applied settings, such as situations of eyewitness testimony.

An exploration of Italian laypeople's belief in how human memory works.

We present the first study to measure the beliefs held by Italian laypeople about how human memory works, using a newly developed tool: the Italian Memory Belief Questionnaire (IMBQ). Research conducted in other countries has demonstrated that beliefs about memory vary widely between different professional and non-professional groups, indicating that limitations exist regarding the dissemination of empirically researched scientific knowledge. To ascertain what Italian people understand about memory-related topics, including eyewitness testimony, repression of traumatic memories and factors influencing memory recall, 301 native Italian participants completed the IMBQ in Study 1. In Study 2, 346 additional participants completed the IMBQ, alongside various additional measures, to examine the construct validity of our new instrument and investigate socio-demographic predictors of memory beliefs. Exploratory factor analysis in Study 1 identified three distinct belief factors that were present in the dataset: eyewitness and memory reliability, trauma and remembering and aspects that improve remembering. Study 2 partially confirmed this factor structure and found IMBQ scores to correlate with existing memory belief questionnaires. Correlations were also found between the IMBQ subscales and measures of fantasy proneness, but not dissociation. In both studies, many Italian laypeople strongly endorsed the notion that controversial topics (i.e., repression) are possible. Contrastingly, Italian laypeople do appear to understand the conceivable inaccuracies of memory in eyewitness settings. Sex, age and education were shown to predict beliefs about memory. Findings are discussed in relation to the importance of addressing misinformation about memory, especially in clinical and forensic settings.

Dimensions of a hyper memory: investigating the factors modulating exceptional retrieval in a single case of highly superior autobiographical memory (HSAM).

Highly Superior Autobiographical Memory (HSAM) is a rare form of exceptional memory, characterised by an ability to recall personal episodes in response to dates. The single case "DT" is one of less than 100 HSAM individuals globally, and little is known about how these individuals organise the vast number of events they can recollect. We administered 2 novel priming tasks to explore navigation between autobiographical memories. In both tasks, a "prime" date appeared on the screen and DT was instructed to access and begin reliving a specific memory from that date. After 3 s, a "target" date appeared, and DT switched to the new memory. Latencies were recorded. Experiment 1 explored the influence of emotional valence on memory navigation. DT was quicker moving from positive or negative memories to neutral memories, compared to between neutral memories, supporting the role of emotionality in connecting memories in HSAM. Experiment 2 investigated semantic content and mental timeline configuration's role in organisation. DT was faster moving forward (e.g., 1996-1997) than backwards (e.g., 2023-2022), indicating a forwards perception of time. No differences were observed regarding semantic content. Results provide insight into DT's memory dimensions and support the use of this task to explore organisation.

Highly Superior Autobiographical Memory (HSAM): A Systematic Review.

Individuals possessing a Highly Superior Autobiographical Memory (HSAM) demonstrate an exceptional ability to recall their own past, excelling most when dates from their lifetime are used as retrieval cues. Fully understanding how neurocognitive mechanisms support exceptional memory could lead to benefits in areas of healthcare in which memory plays a central role and in legal fields reliant on witnesses' memories. Predominantly due to the rareness of the phenomenon, existing HSAM literature is highly heterogenous in its methodologies used. Therefore, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we performed the first systematic review on this topic, to collate the existing behavioural, neuroanatomical, and functional HSAM data. Results from the 20 experimental selected studies revealed that HSAM is categorised by rapidly retrieved, detailed and accurate autobiographical memories, and appears to avoid the normal aging process. Functional neuroimaging studies showed HSAM retrieval seems characterised by an intense overactivation of the usual autobiographical memory network, including posterior visual areas (e.g., the precuneus). Structural neuroanatomical differences do not appear to characterise HSAM, but altered hippocampal resting-state connectivity was commonly observed. We discuss theories of HSAM in relation to autobiographical encoding, consolidation, and retrieval, and suggest future directions for this research.