Psychological Science

How much pleasure we take in eating is more than just how much we enjoy the taste of food. Food involvement - the amount of time we spend on food beyond the immediate act of eating and tasting - is key to the human food experience. We took a biological approach to test whether food-related behaviors, together capturing food involvement, have genetic components and are partly due to inherited variation. We collected data via an internet survey from a genetically informative sample of 419 adult twins (114 monozygotic twin pairs, 31 dizygotic twin pairs, and 129 singletons). Because we conducted this research during the pandemic, we also ascertained how many participants had experienced COVID-19-associated loss of taste and smell. Since these respondents had previously participated in research in person, we measured their level of engagement to evaluate the quality of their online responses. Additive genetics explained 16-44% of the variation in some measures of food involvement, most prominently various aspects of cooking, suggesting some features of the human food experience may be inborn. Other features reflected shared (early) environment, captured by respondents twin status. About 6% of participants had a history of COVID-19 infection, many with transitory taste and smell loss, but all but one had recovered before the survey. Overall, these results suggest that people may have inborn as well as learned variations in their involvement with food. We also learned to adapt to research during a pandemic by considering COVID-19 status and measuring engagement in online studies of human eating behavior.

Adults have been shown to consistently remember and forget certain images despite large individual differences, suggesting a population-wide sensitivity to an images intrinsic memorability--a measure of how successfully an image is remembered. While a decade of research has focused on image memorability among adults, the developmental trajectory of these consistencies in memory is understudied. Here, we investigate by what age children gain adultlike sensitivity to the image memorability effect. We utilized data from Saragosa-Harris et al. (2021), where 137 children aged between 3 and 5 years old encoded animal-scene image pairs and then after a 5-minute, 24-hour, or 1-week delay performed a cued recognition task for each scene target given its animal cue. We tested adults memory of the same scene images using ResMem (Needell & Bainbridge, 2022), a pre-trained deep neural network that predicts adult image memorability scores, and using an online behavioral continuous recognition task (N = 116). Results showed that ResMem predictions, as a proxy of adults memory, predicted scene memory of children by the age of 4 and were the most predictive of childrens memory across ages after a long, 1-week delay. Children at age 3 show non-adult-like consistent memory patterns, implying that the non-adult-like memory patterns were not due to poor memory performance. Instead, 3-year-olds may have consistently used certain visual memory strategies that become less optimal as they age. Our results suggest that adult-like sensitivity to image memorability emerges by the age of 4 through experience. Public Significance StatementThis study strongly suggests that children older than 4 years old tend to remember and forget the same images as adults. We recommend teachers and caregivers to utilize the ResMem DNN to select memorable images to be used in educational settings.

The anticipation of extrinsic reward facilitates memory formation. However, it is unclear how reward following memory retrieval influences the information that is retrieved and later remembered. Here, we conducted four behavioral experiments (N=42 male/female young adults per experiment) in which we manipulated retrieval practice reward delivery. Across all experiments, participants studied word-image pairs and then completed two rounds of retrieval practice, followed by a final recognition test. Participants made vividness judgments during retrieval practice and in three of four experiments each response had a 50% chance of yielding positive feedback. We find that repeated rewards following retrieval practice facilitate later memory whereas low vivid retrieval practice impairs later memory. Together, these results suggest that the benefit of both retrieval practice and reward may be dependent on the strength of the memory that is retrieved.

AbstractResearch has implicated spatial ability as a robust predictor of aptitude, interest, and choice in STEM education and career pursuits. We address three under-explored questions regarding the role of spatial ability in STEM. First, can spatial ability consistently predict STEM success beyond other cognitive skills? Second, what aspects of spatial ability, if any, can predict success in STEM more accurately? Third, to what extent can genetic and environmental factors account for these predictions? We addressed these questions by leveraging data from the Twins Early Development Study (N = 3,936; age range = 16-22) and using 16 tests that assessed three domains of spatial ability: navigation, object manipulation, and visualization. Results show that all three domains are highly predictive of STEM educational outcomes, especially STEM degree choice. These associations persisted after accounting for verbal and general cognitive abilities (g), albeit attenuated. Associations were strongest for tests of object manipulation (e.g., 2D and 3D drawing, pattern assembly and mental rotation). Genetic factors accounted for most of the observed associations between spatial ability and STEM outcomes (62% - 86%) --genetic variance was mostly shared with g ([~] 40%) and, to a lesser extent, verbal ability ([~] 25%). Our findings highlight the potential utility of spatial ability as a specific predictor of success in STEM education and career choice beyond other cognitive abilities. Screening for and training spatial skills is likely useful for identifying potential, fostering talent, and improving outcomes in STEM. Significance StatementLeveraging a comprehensive battery of 16 spatial ability tests across multiple domains, we show that spatial ability has specific utility for predicting success in STEM education. Spatial skills predict success in STEM above and beyond other cognitive abilities, particularly when it comes to STEM engagement and pursuing further STEM education. Thus, spatial skills may be a fruitful target for policymakers, stakeholders, and industries looking to develop interventions, identify and foster talent, and reduce outcome disparities.

When individuals view the same visual input, they often differ in their aesthetic appeal judgments, yet why people differ remains largely unclear. Here, we tested whether individual differences in aesthetic experience are linked to differences in visual exploration. In two experiments, participants watched the documentary "Home" while their eye movements were recorded. In Experiment 1, participants continuously rated aesthetic experience throughout the movie, whereas in Experiment 2, they watched the first half without a task and rated aesthetic experience only during the second half. Inter-individual similarity in gaze patterns, assessed using fixation heatmaps across time, predicted similarity in aesthetic appeal judgments in both experiments. Notably, in Experiment 2, gaze similarity during free viewing in the first half of the movie predicted similarity in aesthetic ratings during the second half, indicating that incidental eye movement patterns predict aesthetic experiences. Together, these results show that shared gaze patterns are linked to shared aesthetic experiences under naturalistic, dynamic viewing conditions.

Set-size effects in change detection is often used to investigate the capacity limits of dividing attention. Such capacity limits have been attributed to a variety of processes including perception, memory encoding, memory storage, memory retrieval, comparison and decision. In this study, we investigated the locus of the effect of increasing set size from 1 to 2. To measure purely attentional effects and not other phenomena such as crowding, a precue was used to manipulate relevant set size and keep the display constant across conditions. The task was to detect a change in the orientation of 1 or 2 Gabor patterns. The locus of the capacity limits was determined by varying when observers were cued to the only stimulus that was relevant. We began by measuring the baseline set-size effect in an initial experiment. In the next experiment, a 100% valid postcue was added to test for an effect of decision. This postcue did not change the set-size effects. In the critical experiments, a 100% valid cue was provided during the retention interval between displays, or only one stimulus was presented in the second display (local recognition). For both of these conditions, there was little or no set-size effect. This pattern of results was found for both hard-to-discriminate stimuli typical of perception experiments and easy-to-discriminate stimuli typical of memory experiments. These results are consistent with capacity limits in memory retrieval, and/or comparison. For these set sizes, the results are not consistent with capacity limits in perception, memory encoding or memory storage. Significance SectionThe change detection paradigm is often used to demonstrate effects of divided attention. But it is not clear whether these effects are due to perception, memory, or judgment and decision. In this article, we present new evidence that the divided attention effect in change detection is due to limits in memory retrieval or comparison processes. These results are not consistent with limits in perception, memory encoding or memory storage.

The decoy effect occurs when adding an inferior third option biases choice between two others, even though the decoy is rarely chosen. While robust in value-based decisions, evidence in perceptual tasks is mixed. Using the rhesus-macaque paradigm from Parrish et al. (2015), we tested whether a perceptual decoy effect generalizes to humans. Participants (n = 50) completed 400 trials. Contrary to our preregistered prediction, we found no reliable decoy effect. Accuracy improved on the hardest trials (Level 1) when a decoy was present, response times were slower in decoy conditions than baseline, and accuracy was higher for tall versus wide rectangles, consistent with the vertical-horizontal asymmetry. The relatively wide spacing of stimuli may have reduced grouping and attentional clustering; because spacing was not manipulated, this remains a hypothesis for future tests. Results suggest that context effects in perceptual choice operate under narrower boundary conditions than in value-based domains.

Pupil diameter reflects not only reflexive responses to light but also spontaneous fluctuations in arousal. Such pre-stimulus fluctuations may shape visual performance, yet it remains unclear whether they only affect perceptual sensitivity or decision processes in near-threshold tasks, or instead influence the temporal availability of sensory information even for highly visible stimuli. We tested whether pupil-linked arousal modulates iconic memory, a high-capacity but short-lived visual store bridging sensory encoding and short-term memory. Based on a model in which a brief stimulus evokes an internal response decaying over a few hundred milliseconds, we hypothesized that increased arousal enhances performance either by amplifying the initial response or by slowing its decay. Thirty-seven participants viewed brief displays of six oriented stimuli, followed by a cue after a variable stimulus-cue onset asynchrony indicating which item to report. Pre-stimulus pupil diameter was continuously recorded, and behavioral data were fitted with an exponential decay function estimating initial stimulus availability, decay rate, and asymptotic performance. Larger pre-stimulus pupil dilation was associated with higher initial stimulus availability but faster decay of the iconic trace, while information transferred into short-term memory and confidence ratings remained unaffected. These findings demonstrate that spontaneous fluctuations in arousal shape the temporal dynamics of sensory persistence. Elevated arousal boosts the initial strength of visual representations but shortens their duration, suggesting that arousal adaptively prioritizes rapid updating of visual input over prolonged stability. Significance StatementHow does arousal shape the earliest stages of visual memory? By leveraging a criterion-free partialreport task that emphasizes the temporal availability of sensory information, we show that spontaneous pre-stimulus pupil dilation - an index of arousal - selectively boosts the initial availability of iconic memory while accelerating its decay. This dual effect suggests that arousal tunes the temporal dynamics of sensory persistence, potentially prioritizing rapid updating of incoming information. These findings advance the understanding of how state-dependent fluctuations in arousal shape early perception in a context that minimizes decision-bias confounds.

Child educational development is associated with major psychological, social, economic and health milestones throughout the life course. Understanding the early origins of educational inequalities and their reproduction across generations is therefore crucial. Recent genomic studies provide novel insights in this regard, uncovering "genetic nurture" effects, whereby parental genotypes influence offsprings educational development via environmental pathways rather than genetic transmission. These findings have yet to be systematically appraised. We conducted the first systematic review and meta-analysis to quantify genetic nurture effects on educational outcomes and investigate key moderators. Twelve studies comprising 38,654 distinct parent(s)-offspring pairs or trios from eight cohorts were included, from which we derived 22 estimates of genetic nurture effects. Multilevel random effects models showed that the effect of genetic nurture on offsprings educational outcomes ({beta}genetic nurture = 0.08, 95% CI [0.07, 0.09]) was about half the size of direct genetic effects ({beta}direct genetic = 0.17, 95% CI [0.13, 0.20]). Maternal and paternal genetic nurture effects were similar in magnitude, suggesting comparable roles of mothers and fathers in determining their childrens educational outcomes. Genetic nurture effects were largely explained by parental educational level and family socioeconomic status, suggesting that genetically influenced environments play an important role in shaping child educational outcomes. Even after accounting for genetic transmission, we provide evidence that environmentally mediated parental genetic influences contribute to the intergenerational transmission of educational outcomes. Further exploring these downstream environmental pathways may inform educational policies aiming to break the intergenerational cycle of educational underachievement and foster social mobility. Public Significance StatementThis meta-analysis demonstrates that parents genetics influence their childrens educational outcomes through the rearing environments that parents provide. This "genetic nurture" effect is largely explained by family socioeconomic status and parental education level, is similar for mothers and fathers (suggesting that both parents equally shape their childrens educational outcomes) and is about half the size of direct genetic effects on childrens educational outcomes. Interventions targeting such environmental pathways could help to break the intergenerational cycle of educational underachievement and foster social mobility.

Social factors of health (SFOH) are critical determinants of human traits but are rarely incorporated into genetic models. Here, we assess how participant-completed SFOH survey data influence heritability estimates and trait variance in 85,963 diverse All of Us participants spanning multiple ancestries and racial identities. We summarized SFOH survey data using multiple correspondence analysis (MCA) into axes representing distinct social dimensions (e.g., social support, perceived stress) and developed a Social Similarity Index (SSI) to capture social environment similarity among individuals. To analyze trait heritability, we used Haseman-Elston (HE) regression for its sensitivity to residual structure. Including SFOH measures as covariates in HE regression models significantly reduced heritability estimates for four of 18 traits, three of which are anthropometric: body mass index, hip circumference, waist circumference, and HDL cholesterol. This suggests that unmodeled social structure can be misattributed to genetic effects. Though several SFOH measures have non-zero heritability when adjusting for three genetic principal components (h2{approx} 0.01-0.09), these are reduced to similar estimates when adjusting for seven genetic principal components (h2{approx} 0.01-0.02). This convergence across SFOH measures, which capture different social dimensions, indicates that SFOH measures capture population stratification, emphasizing their utility for reducing confounding in heritability estimates. SFOH measures were also associated with trait variance, with anthropometric traits--those with reduced heritability--exhibiting the most extensive dispersion effects. This implies that social environment influences trait variability. Our findings highlight the necessity of including social and environmental factors in genetic studies to reduce potential confounding.

Pretend play is a hallmark behavior in childhood where children create nonliteral meanings. Empirical data supporting the role of social cognition and the decoupling from literality are still scarce during early development. We explored here how the comprehension of pretense affects the visual exploratory behavior of toddlers (n = 44) and adults (n = 65) when they were exposed to short video clips in which an actress performed either real actions (e.g., eating jelly) or pretend actions (e.g., pretending to eat with imaginary food), while varying the complexity of those actions. We analyzed participants exploration of the face in the videos as exploitation of social information. We showed that all observers paid more attention to the face in pretend scenarios than in real ones, measured as longer total looking time in adults and more fixations and revisits to the face in both age groups. We also found more gaze shifts (a measure of information sampling) between the face and the moving hand in the pretend videos in both age groups, mainly at the initial stages of the actions. Additionally, analyses of the scanpaths structure using gaze entropy showed less order in the exploration of pretend videos in both age groups, suggesting that pretense involved greater uncertainty and increased information seeking. The less structured trajectories were observed again mainly in complex pretend scenarios. Taken together, our gaze results indicate that from its developmental origins, the comprehension of pretense relies on social processes linked with information seeking and exploration. Significance StatementDevelopmental theories have long debated whether pretend games are born in conjunction with social capacities in the second year or become integrated later in life. Our study shows that, much like adults, toddlers visually explore pretend scenes gathering more social information and in a less structured manner compared to real-world scenarios, suggesting that the emerging capacity to play with the meaning of things is linked with that of thinking of other minds early in life.

Computational models and neurobehavioral data suggest that encoding variability affects forced-choice mnemonic discrimination. Here, we experimentally manipulated encoding variability on the forced-choice Mnemonic Similarity Task by varying stimulus repetitions during encoding. We first generated predictions from a global matching model. Behavioral data supported all predictions. Across most conditions, repetitions consistently enhanced mnemonic discrimination; however, when encoding variability was induced by 3-repetitions of the original version of the non-corresponding lure and 1-repetition of the target during learning, individuals exhibited increased interference. These findings provide further insight into theories of human memory, especially the effect of stimulus repetition on mnemonic discrimination.

Noncognitive skills such as motivation and self-regulation, are partly heritable and predict academic achievement beyond cognitive skills. However, how the relationship between noncognitive skills and academic achievement changes over development is unclear. The current study examined how cognitive and noncognitive skills contribute to academic achievement from ages 7 to 16 in a sample of over 10,000 children from England and Wales. Noncognitive skills were increasingly predictive of academic achievement across development. Twin and polygenic scores analyses found that the contribution of noncognitive genetics to academic achievement became stronger over the school years. Results from within-family analyses indicated that associations with noncognitive genetics could not simply be attributed to confounding by environmental differences between nuclear families and are consistent with a possible role for evocative/active gene-environment correlations. By studying genetic effects through a developmental lens, we provide novel insights into the role of noncognitive skills in academic development.

The most highly predictive polygenic scores in the behavioural sciences are for cognitive traits, especially general cognitive ability (g) and educational attainment. We combined polygenic scores derived from genome-wide association studies of adult g and educational attainment to create adult 'polygenic g scores' which we used to chart the course of cognitive development of 10,000 white British children from toddlerhood through early adulthood. We integrated cross-sectional regression, latent growth curve, and confirmatory factor analysis to systematically characterise cognitive development. Polygenic g score showed minimal prediction in toddlerhood, modest prediction in childhood, and substantial prediction by early adulthood accounting for 12% of the variance. Higher polygenic g scores were associated with faster cognitive growth in latent growth models. Prediction was strongest for a cross-time latent cognitive factor (15%) capturing cognitive ability across development. By integrating polygenic prediction directly into a structural equation model framework, we provided a theoretical upper bound of genetic influences on g under minimal measurement error. We also examined the polygenic g score's prediction of educational achievement, behaviour problems, and anthropometric outcomes and found similar developmental increases in prediction for educational achievement. Together, our findings demonstrate that adult polygenic g scores can be a useful tool for charting the development of cognitive traits.

Every day, we make choices about how much effort we are willing and able to use to achieve the outcomes we desire against the backdrop of constantly shifting effort demands and available rewards. While factors like visual short-term memory and chronic stress levels can predict responses to stable cognitive effort demands, we do not yet know whether they constrain ones choices of higher effort trials for larger rewards when task demands and potential outcomes shift over time. Here, we examined whether these factors predicted the choice to deploy cognitive effort given increasing effort demands and the tendency to deploy effort given shifting reward availability. Undergraduate participants first performed an online visual short-term memory task to assess capacity for visuospatial short-term memory. They then completed a series of choice trials where they could choose between high-effort, high-reward or low-effort, low-reward trials. In two blocks, we varied either the effort required on high-effort trials or the reward offered on both trial types. We found that visual short-term memory predicted the likelihood of choosing high-effort trials given shifting rewards, while chronic stress and everyday preferences for cognitively effortful strategies predicted the tendency to deploy increasing amounts of effort for a stable reward. Furthermore, participants subjective reports show a strong focus on attentional processes, and balancing rewards and losses, when making decisions about how much effort to deploy. These findings shed light on distinct trait-level factors associated with cognitive effort choices given shifting demands and outcomes. Significance statementWe must often choose how much work to put in to complete everyday tasks. However, we do not know what behavioural factors drive these choices in humans when the effort required to complete a task - or potential rewards - shifts over time. In a visual short-term memory task adapted from rodent work, we found that those with higher visual short-term memory ability chose more high effort trials as effort demands increased, while chronic stress and everyday preferences for effortful strategies predicted more effort for a reward. Furthermore, participants described prioritizing sustaining attention in order to successfully complete the task. These findings shed light on distinct trait-level factors associated with cognitive effort choices given shifting demands and outcomes.

Moral judgments may be driven by both principled and opportunistic motivations. Being morally principled is to consistently adhere to a single set of rules about morality and justice. Opportunistic morality rather involves selectively enforcing rules when they are beneficial to ones interests. These two kinds of motivations sometimes pull in the same direction, other times not. Prior studies on moral motivations have mostly focused on principled morality. Opportunistic morality, along with its phenotypic and genetic correlates, remains largely unexamined. Here, utilizing a sample from the Norwegian Twin Registry, consisting of 312 monozygotic-and 298 dizygotic twin pairs (N = 1220), we measure peoples propensity to react to injustice as victims, observers, beneficiaries, and perpetrators of injustice, using the Justice Sensitivity scale. Our genetically informative sample allows a biometric modeling approach that provides increased stringency in inferring latent psychological traits. We find evidence for two substantially heritable traits explaining correlations between Justice Sensitivity facets, which we interpret as a principled justice sensitivity (h2 = .45) leading to increased sensitivity to injustices of all categories, and an opportunistic justice sensitivity (h2 = .69) associated with increased victim sensitivity and a decreased propensity to feel guilt from being a perpetrator. These heritable justice traits share a genetic substrate with broad strategies for cooperation (as measured by altruism and trust) and for selectively benefitting oneself over the adaptive interests of others (as measured by social dominance orientation and support for monopolizing territory and resources), and differ genetically and phenotypically from Big Five personality traits.

Visual working memory (VWM) is traditionally studied while constraining eye movements and limiting access to visual input, yet in natural vision humans constantly explore and resample their environment. Only a few studies have examined VWM utilization when participants were allowed to interact with the environment and found that participants often preferred to resample their environment rather than rely on VWM storage. However, since eye movements were not controlled in these studies, the link between VWM utilization and free visual exploration remained unknown. In two experiments (N = 40), we investigated how visual exploration shapes reliance on VWM versus perceptual input. Participants searched for a common target across two item sets and could either store multiple items for comparison or repeatedly resample the sets by switching between them. Results revealed that when switching was achieved through eye movements, participants consistently relied more on visual resampling and less on VWM; in contrast, when switching required a manual response, they shifted toward greater VWM use. This pattern persisted even when peripheral input was equated, suggesting that natural exploration through eye movements reduces the cognitive cost of acquiring visual information, leading to a strategic reduction in VWM use. Our findings challenge fixation-based approaches to VWM research and highlight the importance of studying cognition under ecological viewing conditions.

Although educational attainment is heritable, its conventional measurement in genetic research as years of education (EduYears) is not designed to reveal potential stage-specific genetic influences across discrete milestones. In two Norwegian cohorts (Norwegian Mother, Father and Child Cohort Study, N = 120,527; Norwegian Twin Registry, N = 8,910), we quantified the genetic contributions to completing high school, bachelors, masters and PhD using genome-wide association studies (GWAS), polygenic indices (PGIs) and twin models. Transition-specific analyses, conditioning on prior success, revealed that observed-scale common-variant heritability (h2SNP) and PGI predictability followed an inverse-U pattern, peaking at the transition into higher education (h2SNP {approx} 0.14; R2Tjur {approx} 0.05) before declining for postgraduate degrees. Genetic correlations (rg) with large-scale GWAS of EduYears (EA4) and intelligence (IQ3) were high for early transitions but declined markedly for later ones (e.g., rg with EA4 from {approx} 0.92 to {approx} 0.38). In cumulative analyses, aggregating liability across prior milestones, the gap between twin- and SNP-based heritability narrowed at higher levels of attainment (h2twin {approx} 0.6[->]0.3; h2SNP {approx} 0.22[->]0.19), while the genetic overlap between distant milestones diminished (rg {approx} 0.92[->]0.71). These patterns, obscured by EduYears metrics, highlight a dynamic genetic architecture across educational milestones, refining polygenic prediction and addressing misconceptions about uniform genetic influences on educational progression.

Non-cognitive skills have previously been associated with a range of health and socioeconomic outcomes, though there has been considerable heterogeneity in published research. Many studies have used cross sectional data and therefore the longitudinal consistency of measures designed to capture non-cognitive skills is poorly understood. Using data from a UK cohort, we assess the consistency of non-cognitive skills over a 17-year period throughout childhood and adolescence, their genomic architecture, and their associations with socioeconomic outcomes. We find that longitudinal measurement consistency is high for behavioural and communication skills but low for other non-cognitive skills, implicating a high noise to signal ratio for many non-cognitive skills. Consistent non-zero heritability estimates and genetic correlations applied to cross-sectional measures are observed only for behavioural difficulties. When aggregating across multiple measurements, we find evidence of low heritability [Formula] for behaviour, communication, self-esteem and locus of control. We find weak correlations between aggregate measures of skills, further supporting cross-sectional measurement error in the non-cognitive measures. Associations between non-cognitive skills and educational outcomes are observed for skills measured in mid to late childhood and these are at most a third of the size of IQ-education associations. These results suggest that individual measures designed to capture non-cognitive skills may be subject to considerable measurement error and provide unreliable indicators of childrens skills. However, aggregate measures that leverage longitudinal data may more reliably identify underlying non-cognitive traits.

Previous work has shown that humans distribute their visual working memory (VWM) resources flexibly across items: the higher the importance of an item, the better it is remembered. A related, but much less studied question is whether people also have control over the total amount of VWM resource allocated to a task. Here, we approach this question by testing whether increasing monetary incentives results in better overall VWM performance. In three experiments, subjects performed a delayed-estimation task on the Amazon Turk platform. In the first two experiments, four groups of subjects received a bonus payment based on their performance, with the maximum bonus ranging from $0 to $10 between groups. We found no effect of the amount of bonus on intrinsic motivation or on VWM performance in either experiment. In the third experiment, reward was manipulated on a trial-by-trial basis using a within-subjects design. Again, no evidence was found that VWM performance depended on the magnitude of potential reward. These results suggest that encoding quality in visual working memory is insensitive to monetary reward, which has implications for resource-rational theories of VWM.