Long-term, multi-event surprise correlates with enhanced autobiographical memory.

Neurobiological and psychological models of learning emphasize the importance of prediction errors (surprises) for memory formation. This relationship has been shown for individual momentary surprising events; however, it is less clear whether surprise that unfolds across multiple events and timescales is also linked with better memory of those events. We asked basketball fans about their most positive and negative autobiographical memories of individual plays, games and seasons, allowing surprise measurements spanning seconds, hours and months. We used advanced analytics on National Basketball Association play-by-play data and betting odds spanning 17 seasons, more than 22,000 games and more than 5.6 million plays to compute and align the estimated surprise value of each memory. We found that surprising events were associated with better recall of positive memories on the scale of seconds and months and negative memories across all three timescales. Game and season memories could not be explained by surprise at shorter timescales, suggesting that long-term, multi-event surprise correlates with memory. These results expand notions of surprise in models of learning and reinforce its relevance in real-world domains.

Semantic associates create retroactive interference on an independent spatial memory task.

Semantic similarity between stimuli can lead to false memories and can also potentially cause retroactive interference (RI) for veridical memories. Here, participants first learned spatial locations for "critical" words that reliably produce false memories in the Deese-Roediger-McDermott paradigm. Next, participants centrally viewed words that were semantically associated with half of the critical words. Finally, participants retrieved the spatial locations for the critical words. We found that spatial memory was worse for critical words whose semantic associates were shown versus not shown, suggesting that semantic relatedness caused RI. This effect occurred in three experiments when the interfering information was presented shortly before the spatial test but not when there was a 1-hour delay before the test, nor when the order of the spatial learning and associate learning phases were reversed. These findings suggest that RI can occur solely via semantic associates when all relevant responses and no distracting responses were available at retrieval. We consider these findings to be an example of cue overload, whereby cues can be overloaded indirectly via semantic associates, and to support the importance of both semantic similarity and temporal context in RI. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Semantic relatedness retroactively boosts memory and promotes memory interdependence across episodes.

Two fundamental issues in memory research concern when later experiences strengthen or weaken initial memories and when the two memories become linked or remain independent. A promising candidate for explaining these issues is semantic relatedness. Here, across five paired-associate learning experiments (N=1000), we systematically varied the semantic relatedness between initial and later cues, initial and later targets, or both. We found that learning retroactively benefited long-term memory performance for semantically related words (vs. unshown control words), and these benefits increased as a function of relatedness. Critically, memory dependence between initial and later pairs also increased with relatedness, suggesting that pre-existing semantic relationships promote interdependence for memories formed across episodes. We also found that modest retroactive benefits, but not interdependencies, emerged when subjects learned via studying rather than practice testing. These findings demonstrate that semantic relatedness during new learning retroactively strengthens old associations while scaffolding new ones into well-fortified memory traces.

Spatial gist extraction during human memory consolidation.

Theories of memory consolidation suggest that initially rich, vivid memories become more gist-like over time. However, it is unclear whether gist-like representations reflect a loss of detail through degradation or the blending of experiences into statistical averages, and whether the strength of these representations increases, decreases, or remains stable over time. We report three behavioral experiments that address these questions by examining distributional learning during spatial navigation. In Experiment 1, human subjects navigated a virtual maze to find hidden objects with locations varying according to spatial distributions. After 15 minutes, 1 day, 7 days, or 28 days, we tested their navigation performance and explicit memory. In Experiment 2, we created spatial distributions with no object at their mean locations, thereby disentangling learned object exemplars from statistical averages. In Experiment 3, we created only a single, bimodal distribution to avoid possible confusion between distributions and administered tests after 15 minutes or 28 days. Across all experiments, and for both navigation and explicit tests, representations of the spatial distributions were present soon after exposure, but then receded over time. These findings suggest gist-like representations do not improve over time, helping to clarify the temporal dynamics of consolidation in human learning and memory. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Perceptions of School Shooters Depend on Prior Criminal Record but Not Targeted Age Group.

Individuals with a prior criminal record are viewed more negatively than those with a clean record, which is often exemplified in harsher sentencing, higher risk assessment ratings, and higher psychopathy ratings. However, what has not yet been explored is whether the age of the targeted victim population (children vs. adults) affects these perceptions. Given that school shooting incidents are a current societal issue, this study aimed to investigate whether the presence of a prior criminal record and age of the victim population affect decisions regarding school shooting offenders. Participants were exposed to school shooting vignettes describing the offender (prior criminal record vs. not) and targeted victims (children vs. adults). They were asked to determine an appropriate sentence and rate the offender's risk of future violence and psychopathy score. Violence risk ratings (measured by the Historical Clinical Risk Management-20 [HCR-20]) and psychopathy ratings (measured by the Psychopathy Checklist-Revised [PCL-R]) depended on the presence of a prior criminal record, such that those with a prior criminal record were perceived as a greater violence risk and as exhibiting more psychopathic traits than their clean-record counterparts. However, punishment severity did not depend on prior criminal record. Likewise, age group of the targeted population had no effect on participants' perceptions of school shooting offenders. These findings contribute to our knowledge of how offender- and incident-specific factors affect perceptions, which has important implications for understanding which factors affect impartiality within our criminal justice system.

Impact of an Internet-Based Lifestyle Intervention on Behavioral and Psychosocial Factors During Postpartum Weight Loss.

OBJECTIVE: This cluster randomized trial tested whether an effective internet-based weight-loss intervention for low-income, postpartum women resulted in greater improvements in targeted social cognitive theory (SCT) constructs and psychosocial outcomes. METHODS: Fit Moms/Mamás Activas was a 12-month cluster randomized controlled trial of 370 postpartum women at 12 Special Supplemental Nutrition Program for Women, Infants, Children (WIC) clinics that were randomly assigned to intervention or standard WIC. SCT constructs (weight-control behaviors, cognitive restraint, disinhibition, self-efficacy, social support, body image) and psychosocial outcomes (depressive symptoms and stress) were measured at study entry and after 6 and 12 months. RESULTS: The intervention versus standard WIC resulted in greater 12-month increases in weight-control behaviors (3.28 points [95% CI: 1.06-5.50]), self-monitoring of weight and eating (2.28 points [1.17-3.40]), and cognitive restraint (1.93 points [0.78-3.08]) (all P ≤ 0.004). The intervention effect was only modestly (ηp 2 = 0.02) mediated by improvements in these factors. No significant group by time effect was observed for disinhibition, self-efficacy, social support, body image, depressive symptoms, or stress. CONCLUSIONS: Among low-income postpartum women, an effective internet-based weight-loss program resulted in improved weight-control behaviors and cognitive restraint but did not affect other SCT targets and psychosocial outcomes.

Rationale and design of a randomized controlled trial examining oral administration of bisphenol A on hepatic glucose production and skeletal muscle insulin sensitivity in adults.

Previous observational studies have shown that the endocrine disrupting chemical bisphenol A (BPA) is associated with type 2 diabetes, but few studies have examined direct effects of BPA on human health. The purpose of this study is to determine whether orally administered BPA at the US Environmental Protection Agency (EPA) safe dose of 50 µg/kg body weight has an adverse effect on hepatic glucose production and skeletal muscle insulin sensitivity. Forty, non-habitually active, healthy adults of normal weight will be enrolled. Participants will begin with a 2-day baseline energy balance diet low in bisphenols in which urine and blood will be collected, and standard tests performed to assess the primary outcome measures of hepatic glucose production (via [6,6-2H] glucose infusion) and skeletal muscle insulin sensitivity (via euglycemic hyperinsulinemic clamp technique). Secondary outcome measures are fasting hormones/endocrine factors (insulin, glucose, C-peptide, Pro-insulin, adiponectin, 17-beta-estradiol, free fatty acids) related to the pathogenesis of type 2 diabetes. Participants will then be randomly assigned to a 4-day energy balance diet plus oral administration of BPA at 50 µg/kg body weight (Diet + BPA) or 4-day energy balance diet plus oral administration of placebo (Diet + No BPA); all outcome measures will be reassessed after 4 days. Findings from this study will provide a framework for other studies in this area, and provide much needed experimental evidence using gold standard measures as to whether oral BPA administration over several days poses any risk of type 2 diabetes.

No Change in Executive Function or Stress Hormones Following a Bout of Moderate Treadmill Exercise in Preadolescent Children.

Several studies suggest that acute bouts of exercise improve executive function in preadolescent children. However, the mechanisms underlying these effects are not completely understood. Specifically, no studies have examined the relationship between the stress hormone response to exercise and improvements in executive function in preadolescent children. The purpose of this study was to examine the effects of a bout of moderate intensity exercise versus rest on working memory (List Sorting Working Memory Task) and selective inhibition/attention (Eriksen flanker task) in preadolescent children, as well as to investigate whether changes in stress hormones (salivary cortisol and alpha-amylase) could explain any differences in performance on these tasks. Twenty-four children completed both a 30-minute moderate intensity bout of treadmill walking and seated rest in a laboratory setting. Tests of executive function and salivary stress hormone analyses were completed before and after each condition. 2x2 Repeated Measures ANOVAs were used to test the effects of time, condition, and time*condition on all executive function and hormonal outcomes. Linear regression models were used to determine if changes in executive function measures were related to changes in stress hormones in the exercise condition. Likely due to methodological limitations, there were no effects of time, condition, nor an interactive effect on working memory, selective inhibition, salivary cortisol, or salivary alpha-amylase. However, there was a trend observed, where the magnitude of the increase in salivary alpha-amylase levels in the exercise condition marginally predicted the improvement in reaction time on the Eriksen flanker task. This suggests that exercise-induced changes in alpha-amylase may underlie improvements in executive function and highlights the need for additional research to more fully understand these relationships in preadolescent children.

Residual effects of emotion are reflected in enhanced visual activity after sleep.

Research has investigated how sleep affects emotional memory and how emotion enhances visual processing, but these questions are typically asked by re-presenting an emotional stimulus at retrieval. For the first time, we investigate whether sleep affects neural activity during retrieval when the memory cue is a neutral context that was previously presented with either emotional or nonemotional content during encoding. Participants encoded scenes composed of a negative or neutral object on a neutral background either in the morning (preceding 12 hours awake; wake group) or evening (preceding 12 hours including a night of sleep; sleep group). At retrieval, participants viewed the backgrounds without their objects, distinguishing new backgrounds from those previously studied. Occipital activity was greater within the sleep group than the wake group specifically during the successful retrieval of neutral backgrounds that had been studied with negative (but not neutral) objects. Moreover, there was enhanced connectivity between the middle occipital gyrus and hippocampus following sleep. Within the sleep group, the percentage of REM sleep obtained correlated with activity in the middle occipital gyrus, lingual gyrus, and cuneus during the successful retrieval of neutral backgrounds previously paired with negative objects. These results confirm that emotion affects neural activity during retrieval even when the cues themselves are neutral, and demonstrate, for the first time, that this residual effect of emotion on visual activity is greater after sleep and may be maximized by REM sleep.

Sleep restriction can attenuate prioritization benefits on declarative memory consolidation.

As chronic sleep restriction is a widespread problem among adolescents, the present study investigated the effects of a 1-week sleep restriction (SR) versus control period on the consolidation of long-term memory for prose passages. We also determined whether the benefit of prioritization on memory is modulated by adequate sleep occurring during consolidation. Fifty-six healthy adolescents (25 male, aged 15-19 years) were instructed to remember a prose passage in which half of the content was highlighted (prioritized), and were told that they would receive an additional bonus for remembering highlighted content. Following an initial free recall test, participants underwent a 7-night period in which they received either a 5-h (SR) or 9-h (control) nightly sleep opportunity, monitored by polysomnography on selected nights. Free recall of the passage was tested at the end of the sleep manipulation period (1 week after encoding), and again 6 weeks after encoding. Recall of highlighted content was superior to that of non-highlighted content at all three time-points (initial, 1 week, 6 weeks). This beneficial effect of prioritization on memory was stronger 1 week relative to a few minutes after encoding for the control, but not the SR group. N3 duration was similar in the control and SR groups. Overall, the present study shows that the benefits of prioritization on memory are enhanced over time, requiring time and sleep to unfold fully. Partial sleep deprivation (i.e. 5-h nocturnal sleep opportunity) may attenuate such benefits, but this may be offset by preservation of N3 sleep duration.

The impact of napping on memory for future-relevant stimuli: Prioritization among multiple salience cues.

Prior research has demonstrated that sleep enhances memory for future-relevant information, including memory for information that is salient due to emotion, reward, or knowledge of a later memory test. Although sleep has been shown to prioritize information with any of these characteristics, the present study investigates the novel question of how sleep prioritizes information when multiple salience cues exist. Participants encoded scenes that were future-relevant based on emotion (emotional vs. neutral), reward (rewarded vs. unrewarded), and instructed learning (intentionally vs. incidentally encoded), preceding a delay consisting of a nap, an equivalent time period spent awake, or a nap followed by wakefulness (to control for effects of interference). Recognition testing revealed that when multiple dimensions of future relevance co-occur, sleep prioritizes top-down, goal-directed cues (instructed learning, and to a lesser degree, reward) over bottom-up, stimulus-driven characteristics (emotion). Further, results showed that these factors interact; the effect of a nap on intentionally encoded information was especially strong for neutral (relative to emotional) information, suggesting that once one cue for future relevance is present, there are diminishing returns with additional cues. Sleep may binarize information based on whether it is future-relevant or not, preferentially consolidating memory for the former category. Potential neural mechanisms underlying these selective effects and the implications of this research for educational and vocational domains are discussed. (PsycINFO Database Record

Sleep and cortisol interact to support memory consolidation.

Separate lines of research have demonstrated that rises in cortisol can benefit memory consolidation, as can the occurrence of sleep soon after encoding. For the first time, we demonstrate that pre-learning cortisol interacts with sleep to benefit memory consolidation, particularly for negative arousing items. Resting cortisol levels during encoding were positively correlated with subsequent memory, but only following a period of sleep. There was no such relation following a period of wakefulness. Using eye tracking, we further reveal that for negative stimuli, this facilitative effect may arise because cortisol strengthens the relationship between looking time at encoding and subsequent memory. We suggest that elevated cortisol may "tag" attended information as important to remember at the time of encoding, thus enabling sleep-based processes to optimally consolidate salient information in a selective manner. Neuroimaging data suggest that this optimized consolidation leads to a refinement of the neural processes recruited for successful retrieval of negative stimuli, with the retrieval of items attended in the presence of elevated cortisol and consolidated over a night of sleep associated with activity in the amygdala and vmPFC.

Eye tracking, cortisol, and a sleep vs. wake consolidation delay: combining methods to uncover an interactive effect of sleep and cortisol on memory.

Although rises in cortisol can benefit memory consolidation, as can sleep soon after encoding, there is currently a paucity of literature as to how these two factors may interact to influence consolidation. Here we present a protocol to examine the interactive influence of cortisol and sleep on memory consolidation, by combining three methods: eye tracking, salivary cortisol analysis, and behavioral memory testing across sleep and wake delays. To assess resting cortisol levels, participants gave a saliva sample before viewing negative and neutral objects within scenes. To measure overt attention, participants' eye gaze was tracked during encoding. To manipulate whether sleep occurred during the consolidation window, participants either encoded scenes in the evening, slept overnight, and took a recognition test the next morning, or encoded scenes in the morning and remained awake during a comparably long retention interval. Additional control groups were tested after a 20 min delay in the morning or evening, to control for time-of-day effects. Together, results showed that there is a direct relation between resting cortisol at encoding and subsequent memory, only following a period of sleep. Through eye tracking, it was further determined that for negative stimuli, this beneficial effect of cortisol on subsequent memory may be due to cortisol strengthening the relation between where participants look during encoding and what they are later able to remember. Overall, results obtained by a combination of these methods uncovered an interactive effect of sleep and cortisol on memory consolidation.

Oversimplification in the study of emotional memory.

This Short Review critically evaluates three hypotheses about the effects of emotion on memory: First, emotion usually enhances memory. Second, when emotion does not enhance memory, this can be understood by the magnitude of physiological arousal elicited, with arousal benefiting memory to a point but then having a detrimental influence. Third, when emotion facilitates the processing of information, this also facilitates the retention of that same information. For each of these hypotheses, we summarize the evidence consistent with it, present counter-evidence suggesting boundary conditions for the effect, and discuss the implications for future research.

Contributors to hypervigilance in a military and civilian sample.

Hypervigilance toward ambiguous or threatening stimuli is a prominent feature in many trauma survivors including active and returning soldiers. This study set out to investigate the factors that contribute to hypervigilance in a mixed sample. One hundred forty-five individuals, 50 of whom were war zone veterans, filled out a series of questionnaires including the Hypervigilance Questionnaire (HVQ; Kimble, Fleming, & Bennion, 2009). Other participants included military cadets, college undergraduates, and a traumatized community sample. In this sample, a history of military deployment and posttraumatic stress disorder symptoms independently predicted hypervigilance. The findings suggest that deployment to a war zone, in and of itself, can lead to hypervigilant behavior. Therefore, characterizing hypervigilance as pathological in a veteran sample must be done so with caution.