Neurobiological sensitivity to popular peers moderates daily links between social media use and affect.

Social media behaviors increase during adolescence, and quantifiable feedback metrics (e.g., likes, followers) may amplify the value of social status for teens. Social media's impact on adolescents' daily affect may be exacerbated given the neurodevelopmental changes that increase youths' sensitivity to socio-emotional information. This study examines whether neurobiological sensitivity to popularity moderates daily links between social media use and affect. Adolescents (N = 91, Mage=13.6 years, SDage=0.6 years) completed an fMRI task in which they viewed faces of their high (>1 SD above the mean) and low (<1 SD below the mean) popular peers based on peer-nominated sociometric ratings from their school social networks. Two years later, adolescents reported their time spent on social media and affect daily for two weeks. Neural tracking of popularity in the ventromedial and dorsomedial prefrontal cortex moderated the association between time on social media and affect. Specifically, adolescents who tracked high popular peers in the vmPFC reported more positive affect on days when they used social media more. Adolescents who tracked low popular peers in the vmPFC and dmPFC reported more negative affect on days when they used social media more. Results suggest that links between social media and affect depend on individual differences in neural sensitivity to popularity.

Neural tracking of social hierarchies in adolescents' real-world social networks.

In the current study, we combined sociometric nominations and neuroimaging techniques to examine adolescents' neural tracking of peers from their real-world social network that varied in social preferences and popularity. Adolescent participants from an entire school district (N = 873) completed peer sociometric nominations of their grade at school, and a subset of participants (N = 117, Mage = 13.59 years) completed a neuroimaging task in which they viewed peer faces from their social networks. We revealed two neural processes by which adolescents track social preference: (1) the fusiform face area, an important region for early visual perception and social categorization, simultaneously represented both peers high in social preference and low in social preference; (2) the dorsolateral prefrontal cortex (DLPFC), which was differentially engaged in tracking peers high and low in social preference. No regions specifically tracked peers high in popularity and only the inferior parietal lobe, temporoparietal junction, midcingulate cortex and insula were involved in tracking unpopular peers. This is the first study to examine the neural circuits that support adolescents' perception of peer-based social networks. These findings identify the neural processes that allow youths to spontaneously keep track of peers' social value within their social network.

Adolescents' neural sensitivity to high and low popularity: Longitudinal links to risk-taking and prosocial behavior.

Adolescents are particularly attuned to popularity within peer groups, which impacts behaviors such as risk-taking and prosocial behavior. Neurodevelopmental changes orient adolescents toward salient social cues in their environment. We examined whether neural regions that track popularity are associated with longitudinal changes in risk-taking and prosocial behavior. During an fMRI scan, adolescents (n = 109, Mage=13.59, SD=0.59) viewed pictures of their popular and unpopular classmates based on sociometric nominations from their social networks. Neural tracking of high popularity in the dorsomedial prefrontal cortex was associated with increases in risk-taking behavior, whereas tracking of low popularity in the right insula was associated with increases in prosocial behavior. Results suggest that individual differences in neural tracking of popularity relate to longitudinal changes in adolescents' social behaviors.

Cascading bidirectional influences of digital media use and mental health in adolescence.

A substantial portion of critical adolescent development is occurring within digital environments. However, certain individual differences may lead adolescents to use digital media in diverse ways. In this chapter we suggest that the way teens use digital media influences how digital media affects their mental health. Further, we propose a model in which these influences, in the context of ongoing development, may have feedback effects on how digital media is subsequently used, thus resulting in a self-perpetuating cycle. Our model suggests that certain developmental risk/protective factors and maladaptive/adaptive digital media behaviors likely perpetuate each other in a cyclical manner each serving to maintain and/or escalate the other. We discuss existing evidence of these processes in psychosocial, identity, incentive processing, and physical health development. Future research focusing on individual differences and self-reinforcing digital media behaviors that manifest these feedback loops may portray a more complete picture of cascading digital media influences across adolescent development.

Association of Habitual Checking Behaviors on Social Media With Longitudinal Functional Brain Development.

Importance: Social media platforms provide adolescents with unprecedented opportunities for social interactions during a critical developmental period when the brain is especially sensitive to social feedback. Objective: To explore how adolescents' frequency of checking behaviors on social media platforms is associated with longitudinal changes in functional brain development across adolescence. Design, Setting, and Participants: A 3-year longitudinal cohort study of functional magnetic resonance imaging (fMRI) among sixth- and seventh-grade students recruited from 3 public middle schools in rural North Carolina. Exposures: At wave 1, participants reported the frequency at which they checked Facebook, Instagram, and Snapchat. Main Outcome or Measure: Neural responses to the Social Incentive Delay task when anticipating receiving social feedback, measured annually using fMRI for 3 years. Participants saw a cue that indicated whether the social feedback (adolescent faces with emotional expressions) would be a reward, punishment, or neutral; after a delay, a target appeared and students responded by pressing a button as quickly as possible; a display of social feedback depended on trial type and reaction time. Results: Of 178 participants recruited at age 12 years, 169 participants (mean [SD] age, 12.89 [0.58] years; range, 11.93-14.52 years; 91 [53.8%] female; 38 [22.5%] Black, 60 [35.5%] Latinx, 50 [29.6%] White, 15 [8.9%] multiracial) met the inclusion criteria. Participants with habitual social media checking behaviors showed lower neural sensitivity to social anticipation at age 12 years compared with those with nonhabitual checking behaviors in the left amygdala, posterior insula (PI), and ventral striatum (VS; ß, -0.22; 95% CI, -0.33 to -0.11), right amygdala (ß, -0.19; 95% CI, -0.30 to -0.08), right anterior insula (AI; ß, -0.23; 95% CI, -0.37 to -0.09), and left dorsolateral prefrontal cortex (DLPFC; ß, -0.29; 95% CI, -0.44 to -0.14). Among those with habitual checking behaviors, there were longitudinal increases in the left amygdala/PI/VS (ß, 0.11; 95% CI, 0.04 to 0.18), right amygdala (ß, 0.09; 95% CI, 0.02 to 0.16), right AI (ß, 0.15; 95% CI, 0.02 to 0.20), and left DLPFC (ß, 0.19; 95% CI, 0.05 to 0.25) during social anticipation, whereas among those with nonhabitual checking behaviors, longitudinal decreases were seen in the left amygdala/PI/VS (ß, -0.12; 95% CI, -0.19 to -0.06), right amygdala (ß, -0.10; 95% CI, -0.17 to -0.03), right AI (ß, -0.13; 95% CI, -0.22 to -0.04), and left DLPFC (ß, -0.10, 95% CI, -0.22 to -0.03). Conclusions and Relevance: The results of this cohort study suggest that social media checking behaviors in early adolescence may be associated with changes in the brain's sensitivity to social rewards and punishments. Further research examining long-term associations between social media use, adolescent neural development, and psychological adjustment is needed to understand the effects of a ubiquitous influence on development for today's adolescents.

An open-access accelerated adult equivalent of the ABCD Study neuroimaging dataset (a-ABCD).

As public access to longitudinal developmental datasets like the Adolescent Brain Cognitive Development StudySM (ABCD Study®) increases, so too does the need for resources to benchmark time-dependent effects. Scan-to-scan changes observed with repeated imaging may reflect development but may also reflect practice effects, day-to-day variability in psychological states, and/or measurement noise. Resources that allow disentangling these time-dependent effects will be useful in quantifying actual developmental change. We present an accelerated adult equivalent of the ABCD Study dataset (a-ABCD) using an identical imaging protocol to acquire magnetic resonance imaging (MRI) structural, diffusion-weighted, resting-state and task-based data from eight adults scanned five times over five weeks. We report on the task-based imaging data (n = 7). In-scanner stop-signal (SST), monetary incentive delay (MID), and emotional n-back (EN-back) task behavioral performance did not change across sessions. Post-scan recognition memory for emotional n-back stimuli, however, did improve as participants became more familiar with the stimuli. Functional MRI analyses revealed that patterns of task-based activation reflecting inhibitory control in the SST, reward success in the MID task, and working memory in the EN-back task were more similar within individuals across repeated scan sessions than between individuals. Within-subject, activity was more consistent across sessions during the EN-back task than in the SST and MID task, demonstrating differences in fMRI data reliability as a function of task. The a-ABCD dataset provides a unique testbed for characterizing the reliability of brain function, structure, and behavior across imaging modalities in adulthood and benchmarking neurodevelopmental change observed in the open-access ABCD Study.

Behavioral and brain signatures of substance use vulnerability in childhood.

The prevalence of risky behavior such as substance use increases during adolescence; however, the neurobiological precursors to adolescent substance use remain unclear. Predictive modeling may complement previous work observing associations with known risk factors or substance use outcomes by developing generalizable models that predict early susceptibility. The aims of the current study were to identify and characterize behavioral and brain models of vulnerability to future substance use. Principal components analysis (PCA) of behavioral risk factors were used together with connectome-based predictive modeling (CPM) during rest and task-based functional imaging to generate predictive models in a large cohort of nine- and ten-year-olds enrolled in the Adolescent Brain & Cognitive Development (ABCD) study (NDA release 2.0.1). Dimensionality reduction (n = 9,437) of behavioral measures associated with substance use identified two latent dimensions that explained the largest amount of variance: risk-seeking (PC1; e.g., curiosity to try substances) and familial factors (PC2; e.g., family history of substance use disorder). Using cross-validated regularized regression in a subset of data (Year 1 Fast Track data; n>1,500), functional connectivity during rest and task conditions (resting-state; monetary incentive delay task; stop signal task; emotional n-back task) significantly predicted individual differences in risk-seeking (PC1) in held-out participants (partial correlations between predicted and observed scores controlling for motion and number of frames [rp]: 0.07-0.21). By contrast, functional connectivity was a weak predictor of familial risk factors associated with substance use (PC2) (rp: 0.03-0.06). These results demonstrate a novel approach to understanding substance use vulnerability, which-together with mechanistic perspectives-may inform strategies aimed at early identification of risk for addiction.

Aspects of quality related to the consumption and production of lamb meat. Consumers versus producers.

The purpose of this study was to identify and compare the different evaluations made by the agents at either end of the lamb meat chain, i.e. producers and consumers, in relation to the parameters that consumers use when purchasing lamb meat and the factors that affect the production of quality lamb meat. In addition, consumer segments that can be targeted for action by the different agents in the chain were examined. The study was carried out in Aragón, a region in north east Spain that is a producer and consumer of lamb meat. 371 surveys were carried out on purchasers of lamb meat and 49 surveys on sheep farmers. Bivariant analyses and a cluster analysis were performed. The results suggest that there are certain congruencies and divergences between producers and consumers. Also, a segment of consumers for whom the hygiene and sanitary conditions on the farm, animal welfare and the environment are of great importance were found.

Factors associated with the purchase of designation of origin lamb meat.

As in other products, quality labels that designate the origin of lamb meat are increasingly used by consumers as a cue for inferring the quality of the meat. The aim of the present paper is to identify those factors that most affect the purchase of lamb with an origin quality label. For this purpose a total of 371 questionnaires were carried out in the region of Aragón located in the north east of Spain. This region produces 48.5% of the total amount of lamb meat with a Spanish protected geographical indication, whilst it also has the country's greatest per capita consumption (6.8 kg/person/year). To identify the most determining factors a logistic regression analysis was performed between three groups of buyers, characterised by their degree of loyalty towards purchasing origin quality-labelled lamb. The results show that those buyers who are less loyal to the label pay less attention to the origin of the meat when forming quality expectations at the time of purchase, whilst these are the buyers that place greatest importance on animal feeding as an aspect affecting the final quality of lamb meat. The buyers that are very loyal to the quality label associate this label with a product that offers greater guarantees and is healthier. Lamb meat buyers with medium loyalty to quality labels, consider quality-labelled lamb meat has better intrinsic attributes.

Factors that affect and motivate the purchase of quality-labelled beef in Spain.

The aim of the present study was to identify the factors that affect and motivate the purchase of quality-labelled beef in Spain. For this purpose a total of 364 surveys were carried out on buyers of beef in three Spanish cities. The sample was divided into three groups of buyers according to the frequency with which they buy beef with a quality label. A logistic regression analysis was used to estimate the differences between groups. The results showed the importance of the production region as a quality aspect. In general terms, variables such as income level and lifestyles would seem to be the variables that enable us to discriminate between quality-labelled beef buyers and non-buyers, whereas beef purchasing habits, a greater appreciation of production systems and attitudes towards quality-labelled beef, are the variables that may explain the differences that exist between regular and occasional quality-labelled beef buyers.