Genome-wide association studies (GWAS) and post-GWAS analyses of impulsivity: A systematic review.

Impulsivity is related to a host of mental and behavioral problems. It is a complex construct with many different manifestations, most of which are heritable. The genetic compositions of these impulsivity manifestations, however, remain unclear. A number of genome-wide association studies (GWAS) and post-GWAS analyses have tried to address this issue. We conducted a systematic review of all GWAS and post-GWAS analyses of impulsivity published up to December 2023. Available data suggest that single nucleotide polymorphisms (SNPs) in more than a dozen of genes (e.g., CADM2, CTNNA2, GPM6B) are associated with different measures of impulsivity at genome-wide significant levels. Post-GWAS analyses further show that different measures of impulsivity are subject to different degrees of genetic influence, share few genetic variants, and have divergent genetic overlap with basic personality traits such as extroversion and neuroticism, cognitive ability, psychiatric disorders, substance use, and obesity. These findings shed light on controversies in the conceptualization and measurement of impulsivity, while providing new insights on the underlying mechanisms that yoke impulsivity to psychopathology.

The development of self-other overlap from childhood to adolescence.

This study aimed to clarify the developmental course of self-other overlap from mid-childhood to late adolescence. Results showed that the development of self-other overlap varied across relationship type: whereas self-stranger overlap increased, overlap with mother, father, friend, and classmate all decreased, with that for parents decreasing most.

Patterns of brain activity associated with nostalgia: a social-cognitive neuroscience perspective.

Nostalgia arises from tender and yearnful reflection on meaningful life events or important persons from one's past. In the last two decades, the literature has documented a variety of ways in which nostalgia benefits psychological well-being. Only a handful of studies, however, have addressed the neural basis of the emotion. In this prospective review, we postulate a neural model of nostalgia. Self-reflection, autobiographical memory, regulatory capacity and reward are core components of the emotion. Thus, nostalgia involves brain activities implicated in self-reflection processing (medial prefrontal cortex, posterior cingulate cortex and precuneus), autobiographical memory processing (hippocampus, medial prefrontal cortex, posterior cingulate cortex and precuneus), emotion regulation processing (anterior cingulate cortex and medial prefrontal cortex) and reward processing (striatum, substantia nigra, ventral tegmental area and ventromedial prefrontal cortex). Nostalgia's potential to modulate activity in these core neural substrates has both theoretical and applied implications.

Is implicit social cognition developmentally stable? A longitudinal study.

To examine whether implicit social cognition is developmentally stable or variable, this study investigated three primary types of implicit social cognition (self-esteem, the gender-science stereotype, and racial attitude) across 2 years in a sample of Chinese adolescents and emerging adults (N = 608; 56% female; 15- to 27-year-olds). Rank-order stability analyses indicated that implicit self-esteem and implicit racial attitude manifested low stability (r = .16, .19, respectively), whereas implicit gender-science stereotype was highly stable (r = .75). Latent change score model analyses showed that: (a) the mean level of implicit self-esteem decreased across the 2 years, whereas the mean levels of implicit gender-science stereotype and implicit racial attitude manifested no changes; (b) individual changes were heterogeneous for all the three types of implicit social cognition (while some of the participants manifested increasing tendencies, 15%-46%, the others exhibited decreasing tendencies); (c) 30% of participants manifested similar changes across the three types of implicit social cognition (either increasing or decreasing over time on all three), while the remaining participants exhibited distinct changes across them. Together, these findings indicate that, developmentally, implicit social cognition is variable but also stable, though the degree of variability and stability vary across individuals and domains. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Nostalgia enhances detection of death threat: neural and behavioral evidence.

An experiment examined the potency of nostalgia-a sentimental longing for one's past-to facilitate detection of death-related stimuli, using functional magnetic resonance imaging (fMRI) and behavioral techniques (i.e., judgmental accuracy, reaction times). We hypothesized and found that, at the neural level, nostalgic (relative to control) participants evinced more intense activation in right amygdala in response to death-related (vs. neutral) words. We also hypothesized and found that, at the behavioral level, nostalgic (relative to control) participants manifested greater accuracy in judging whether two death-related (vs. neutral) words belonged in the same category. Exploratory analyses indicated that nostalgic (relative to control) participants did not show faster reaction times to death-related (vs. neutral) words. In all, nostalgia appeared to aid in death threat detection. We consider implications for the relevant literatures.

Dopaminergic and neurotrophic genetic polymorphisms modulate the implicit gender-science stereotype.

Genetic approaches to both the gender-science stereotype and implicit social cognition have received increasing attention in recent years. We explored whether single nucleotide polymorphisms (SNPs) in dopaminergic and neurotrophic systems (i.e., COMT, BDNF genotypes) explain variations in the implicit gender-science stereotype. We genotyped 413 adolescents and assessed their implicit gender-science stereotype with the Implicit Association Test. Replication on a subsample (N = 312) was conducted 2 years later. Results showed that SNP-level variations within the COMT and BDNF genes were consistently associated with the implicit gender-science stereotype in both investigations. These findings suggest that variants in the COMT and BDNF genes may contribute to the variation of implicit gender-science stereotype.

Oxytocin intensifies the mortality salience effect: Novel evidence for the social salience model of oxytocin.

Oxytocin plays an important role in human responses to threat processing. Few studies have directly examined the effects of oxytocin on our response to death-related stimuli. In the current study, 63 participants intranasally received either 32 IU of oxytocin or a placebo and thereafter completed a visual dot-probe task consisting of death-related and non-death related images. The results indicated that oxytocin enhanced participants' vigilance toward death-related images as well as increased their anxiety about and fear of death. Overall, oxytocin amplifies the defensive responses to a mortality threat, supporting the social salience model of oxytocin.

5-HTTLPR polymorphism is associated with nostalgia proneness: The role of neuroticism.

Nostalgia, a sentimental longing for the past, is a self-relevant and social emotion. Nostalgia proneness is associated with alleviation of distress or instability (e.g., neuroticism). Although nostalgia proneness is heritable, the specific molecular contributors to this heritability are unknown. We focused on a polymorphism in the promoter of the serotonin transporter gene (5-HTTLPR) as a possible biological basis of nostalgia proneness, because the serotonin system has been associated with sensitivity to negative experience. Participants (N = 397 adults) who had reported levels of nostalgia proneness were genotyped. A subsample also completed a measure of neuroticism. Participants with the 5-HTTLPR short allele were higher on nostalgia proneness than those without this allele. Neuroticism mediated the relation between 5-HTTLPR and nostalgia proneness. These findings enrich our understanding of the genetic and personality underpinnings of nostalgia.

Affective Experience on Social Networking Sites Predicts Psychological Well-Being Off-Line.

Previous studies have pondered the relevance of social networking sites (SNSs) to psychological well-being, but few have taken online affective experience into consideration. To extend previous research on the relationship between SNSs and psychological well-being, we opted to target emotions experienced while visiting SNSs as a means to predict off-line well-being. In our two studies, we surveyed affective experience on SNSs, overall life satisfaction, and general emotional well-being of young adults who access SNSs regularly. The results consistently demonstrated a positive association between SNS affective experience and off-line well-being. This finding held with SNS activities (Studies 1 and 2) and relevant personality traits (i.e., the Big Five factors, self-esteem; Study 2) considered in simultaneity. Our research highlights the important role of affective experience on SNSs in predicting off-line well-being as well as helps clarify the relationship between SNSs and well-being.

Do Narcissists Enjoy Visiting Social Networking Sites? It Depends on How Adaptive They Are.

Previous evidence suggests that narcissistic people tend to visit social networking sites (SNS) frequently, but the emotions accompanying their engagement on such sites has not been a significant subject of study. Therefore, we examined the relationship between narcissism and the affective experience on SNS in two different samples. To do so, we not only examined narcissism as a whole but also distinguished between adaptive and maladaptive narcissism. Results of the two studies consistently showed that: (1) narcissism as a whole was not correlated with the SNS affective experience; (2) maladaptive narcissism was predictive of a worse affective experience on SNS; and (3) partly due to a positive correlation with self-esteem, adaptive narcissism was associated with a better SNS affective experience. In addition, these findings held with SNS activities considered in simultaneity. The present research extends our understanding of the relationship between narcissism and social networking as well as that between emotion and social networking.

Narcissism and risky decisions: a neurophysiological approach.

Narcissists are prone to risky decision-making, but why? This study tested-via behavioral and event-related potential (ERP) measures-two accounts: deficiencies in error monitoring and deficiencies in action updating. High and low narcissists were engaged in a monetary gambling task by choosing between a high-risk and a low-risk option while the electroencephalogram (EEG) was being recorded. Two ERP components relevant to outcome evaluation-feedback-related negativity (FRN) and P3-were analyzed, with the FRN serving as an index of error monitoring and the P3 as an index of action updating. Generally, high and low narcissists differed in the high-risk condition but not in the low-risk condition. At the behavioral level, high (vs low) narcissists made riskier decisions following high-risk decision outcomes, which was in line with past findings; at the neurophysiological level, while no FRN difference emerged between high and low narcissists, the outcome valence effect (positive vs negative) on the P3 was stronger among low narcissists than high narcissists following high-risk decision outcomes. One possible interpretation of the results is that narcissism is associated with reduced action updating. The findings contribute to the understanding of narcissistic decision-making and self-regulation.

Be Strong Enough to Say No: Self-Affirmation Increases Rejection to Unfair Offers.

We propose that self-affirmation may endow people more psychological resources to buffer against the negative influence of rejecting unfair offers in the classic ultimatum game (UG) and further lead to a stronger tendency to reject those offers. We tested this possibility by conducting an event-related potential (ERP) study about the UG, with the ERP component P3 as an indirect indicator of psychological resources. Participants were randomly assigned to the affirmation or control condition and then completed the UG through electrophysiological recording. As expected, the behavioral data indicated that compared with unaffirmed ones, affirmed participants were more likely to reject unfair UG offers; the electrophysiological data indicated that compared to the unaffirmed, affirmed participants showed a greater P3 in response to the presentation of an offer. These findings suggest that psychological resources may play a role in rejecting others beyond the fairness concern, and additionally shed light on the neural mechanisms underlying self-affirmation.

Narcissism predicts impulsive buying: phenotypic and genetic evidence.

Impulsive buying makes billions of dollars for retail businesses every year, particularly in an era of thriving e-commerce. Narcissism, characterized by impulsivity and materialism, may serve as a potential antecedent to impulsive buying. To test this hypothesis, two studies examined the relationship between narcissism and impulsive buying. In Study 1, we surveyed an online sample and found that while adaptive narcissism was not correlated with impulsive buying, maladaptive narcissism was significantly predictive of the impulsive buying tendency. By investigating 304 twin pairs, Study 2 showed that global narcissism and its two components, adaptive and maladaptive narcissism, as well as the impulsive buying tendency were heritable. The study found, moreover, that the connections between global narcissism and impulsive buying, and between maladaptive narcissism and impulsive buying were genetically based. These findings not only establish a link between narcissism and impulsive buying but also help to identify the origins of the link. The present studies deepen our understanding of narcissism, impulsive buying, and their interrelationship.

The neural response to maternal stimuli: an ERP study.

Mothers are important to all humans. Research has established that maternal information affects individuals' cognition, emotion, and behavior. We measured event-related potentials (ERPs) to examine attentional and evaluative processing of maternal stimuli while participants completed a Go/No-go Association Task that paired mother or others words with good or bad evaluative words. Behavioral data showed that participants responded faster to mother words paired with good than the mother words paired with bad but showed no difference in response to these others across conditions, reflecting a positive evaluation of mother. ERPs showed larger P200 and N200 in response to mother than in response to others, suggesting that mother attracted more attention than others. In the subsequent time window, mother in the mother + bad condition elicited a later and larger late positive potential (LPP) than it did in the mother + good condition, but this was not true for others, also suggesting a positive evaluation of mother. These results suggest that people differentiate mother from others during initial attentional stage, and evaluative mother positively during later stage.

Neural manifestations of implicit self-esteem: an ERP study.

Behavioral research has established that humans implicitly tend to hold a positive view toward themselves. In this study, we employed the event-related potential (ERP) technique to explore neural manifestations of positive implicit self-esteem using the Go/Nogo association task (GNAT). Participants generated a response (Go) or withheld a response (Nogo) to self or others words and good or bad attributes. Behavioral data showed that participants responded faster to the self paired with good than the self paired with bad, whereas the opposite proved true for others, reflecting the positive nature of implicit self-esteem. ERP results showed an augmented N200 over the frontal areas in Nogo responses relative to Go responses. Moreover, the positive implicit self-positivity bias delayed the onset time of the N200 wave difference between Nogo and Go trials, suggesting that positive implicit self-esteem is manifested on neural activity about 270 ms after the presentation of self-relevant stimuli. These findings provide neural evidence for the positivity and automaticity of implicit self-esteem.

A behavioral genetic study of intrapersonal and interpersonal dimensions of narcissism.

Narcissism, characterized by grandiose self-image and entitled feelings to others, has been increasingly prevalent in the past decades. This study examined genetic and environmental bases of two dimensions of narcissism: intrapersonal grandiosity and interpersonal entitlement. A total of 304 pairs of twins from Beijing, China completed the Narcissistic Grandiosity Scale and the Psychological Entitlement Scale. Both grandiosity (23%) and entitlement (35%) were found to be moderately heritable, while simultaneously showing considerable non-shared environmental influences. Moreover, the genetic and environmental influences on the two dimensions were mostly unique (92-93%), with few genetic and environmental effects in common (7-8%). The two dimensions of narcissism, intrapersonal grandiosity and interpersonal entitlement, are heritable and largely independent of each other in terms of their genetic and environmental sources. These findings extend our understanding of the heritability of narcissism on the one hand. On the other hand, the study demonstrates the rationale for distinguishing between intrapersonal and interpersonal dimensions of narcissism, and possibly personality in general as well.

Implicit self-esteem decreases in adolescence: a cross-sectional study.

Implicit self-esteem has remained an active research topic in both the areas of implicit social cognition and self-esteem in recent decades. The purpose of this study is to explore the development of implicit self-esteem in adolescents. A total of 599 adolescents from junior and senior high schools in East China participated in the study. They ranged in age from 11 to 18 years with a mean age of 14.10 (SD = 2.16). The degree of implicit self-esteem was assessed using the Implicit Association Test (IAT) with the improved D score as the index. Participants also completed the Rosenberg Self-Esteem Scale (α = 0.77). For all surveyed ages, implicit self-esteem was positively biased, all ts>8.59, all ps<0.001. The simple correlation between implicit self-esteem and age was significant, r =  -.25, p = 1. 10(-10). A regression with implicit self-esteem as the criterion variable, and age, gender, and age × gender interaction as predictors further revealed the significant negative linear relationship between age and implicit self-esteem, ß = -0.19, t = -3.20, p = 0.001. However, explicit self-esteem manifested a reverse "U" shape throughout adolescence. Implicit self-esteem in adolescence manifests a declining trend with increasing age, suggesting that it is sensitive to developmental or age-related changes. This finding enriches our understanding of the development of implicit social cognition.

Representation of contextually related multiple objects in the human ventral visual pathway.

Real-world scenes usually contain a set of cluttered and yet contextually related objects. Here we used fMRI to investigate where and how contextually related multiple objects were represented in the human ventral visual pathway. Specifically, we measured the responses in face-selective and body-selective regions along the ventral pathway when faces and bodies were presented either simultaneously or in isolation. We found that, in the posterior regions, the response for the face and body pair was the weighted average response for faces and bodies presented in isolation. In contrast, the anterior regions encoded the face and body pair in a mutually facilitative fashion, with the response for the pair significantly higher than that for its constituent objects. Furthermore, in the right fusiform face area, the face and body pair was represented as one inseparable object, possibly to reduce perceptual load and increase representation efficiency. Therefore, our study suggests that the visual system uses a hierarchical representation scheme to process multiple objects in natural scenes: the average mechanism in posterior regions helps retaining information of individual objects in clutter, whereas the nonaverage mechanism in the anterior regions uses the contextual information to optimize the representation for multiple objects.

The etiology of mathematical self-evaluation and mathematics achievement: understanding the relationship using a cross-lagged twin study from age 9 to 12.

The genetic and environmental origins of individual differences in mathematical self-evaluation over time and its association with later mathematics achievement were investigated in a UK sample of 2138 twin pairs at ages 9 and 12. Self-evaluation indexed how good children think they are at mathematical activities and how much they like those activities. Mathematics achievement was assessed by teachers based on UK National Curriculum standards. At both ages self-evaluation was approximately 40% heritable, with the rest of the variance explained by non-shared environment. The results also suggested moderate reciprocal associations between self-evaluation and mathematics achievement across time, with earlier self-evaluation predicting later performance and earlier performance predicting later self-evaluation. These cross-lagged relationships were genetically rather than environmentally mediated.

Resting-state neural activity across face-selective cortical regions is behaviorally relevant.

Interest has increased recently in correlations across brain regions in the resting-state fMRI blood oxygen level-dependent (BOLD) response, but little is known about the functional significance of these correlations. Here we directly test the behavioral relevance of the resting-state correlation between two face-selective regions in human brain, the occipital face area (OFA) and the fusiform face area (FFA). We found that the magnitude of the resting-state correlation, henceforth called functional connectivity (FC), between OFA and FFA correlates with an individual's performance on a number of face-processing tasks, not non-face tasks. Further, we found that the behavioral significance of the OFA/FFA FC is independent of the functional activation and the anatomical size of either the OFA or FFA, suggesting that face processing depends not only on the functionality of individual face-selective regions, but also on the synchronized spontaneous neural activity between them. Together, these findings provide strong evidence that the functional correlations in the BOLD response observed at rest reveal functionally significant properties of cortical processing.