Daily links between objective smartphone use and sleep among adolescents.

INTRODUCTION: Concerns abound on how digital technology such as smartphone use may impair adolescent sleep. Although these linkages are supported in cross-sectional studies, research involving intensive longitudinal assessments and objective measures has called into question the robustness of associations. METHODS: In this study, a sample of ethnically diverse U.S. adolescents (N = 71; Mage = 16.49; 56% girls) wore Fitbit devices and submitted screenshots of their smartphone screen time, pickups, and notifications over a 14-day period in 2021. The Fitbits recorded nightly sleep quality and sleep onset. Adolescents also completed daily diaries reporting the previous night's sleep onset time and sleep quality. RESULTS: On days when adolescents engaged in greater nighttime screen time and, to some extent, pickups relative to their own average, they also had poorer sleep outcomes that night. Greater screen time was associated with later self-reported and Fitbit-recorded sleep onset and poorer self-reported sleep quality. Greater pickups was associated with later self-reported and Fitbit-recorded sleep onset. Smartphone use during the day did not relate to sleep outcomes, indicating the importance of distinguishing nighttime from daytime use. CONCLUSIONS: Parents and clinicians should help adolescents develop healthy digital skills to avoid exacerbating sleep problems that are known to occur during this developmental period.

Neural Tracking of Perceived Parent, but Not Peer, Norms Is Associated with Longitudinal Changes in Adolescent Attitudes about Externalizing Behaviors.

Adolescents' perceptions of parent and peer norms about externalizing behaviors influence the extent to which they adopt similar attitudes, yet little is known about how the trajectories of perceived parent and peer norms are related to trajectories of personal attitudes across adolescence. Neural development of midline regions implicated in self-other processing may underlie developmental changes in parent and peer influence. Here, we examined whether neural processing of perceived parent and peer norms in midline regions during self-evaluations would be associated with trajectories of personal attitudes about externalizing behaviors. Trajectories of adolescents' perceived parent and peer norms were examined longitudinally with functional neuroimaging (n = 165; ages 11-16 years across three waves; 86 girls, 79 boys; 29.7% White, 21.8% Black, 35.8% Latinx, 12.7% other/multiracial). Behavioral results showed perceived parent norms were less permissive than adolescents' own attitudes about externalizing behaviors, whereas perceived peer norms were more permissive than adolescents' own attitudes, effects that increased from early to middle adolescence. Although younger adolescents reported less permissive attitudes when they spontaneously tracked perceived parent norms in the ventromedial and medial pFCs during self-evaluations, this effect weakened as they aged. No brain-behavior effects were found when tracking perceived peer norms. These findings elucidate how perceived parent and peer norms change in parallel with personal attitudes about externalizing behaviors from early to middle adolescence and underscore the importance of spontaneous neural tracking of perceived parent norms during self-evaluations for buffering permissive personal attitudes, particularly in early adolescence.

Longitudinal changes in the value and influence of parent and peer attitudes about externalizing behaviors across adolescence.

This preregistered, longitudinal study examined how much adolescents value and integrate their parents' and peers' attitudes into their own attitudes from early to middle adolescence. Across three waves, participants (N = 172, 91 female, 11-16 years across three waves; 439 data points) decided whether to pay money to learn their parents' or peers' attitudes about externalizing behaviors. Multivariate growth models revealed that adolescents were consistently willing to pay money over time to learn their parents' and peers' attitudes. The value of learning peers'-but not parents'-attitudes predicted changes in personal attitudes during adolescence, and this did not change across age. Moreover, the effect of others' attitude value on social influence weakened from early to middle adolescence, such that early adolescents who highly valued learning the attitudes of others (i.e., paid more) tended to shift their own attitudes more toward those endorsing positive influence, regardless of the source. In contrast, early adolescents who valued learning others' attitudes less were less susceptible to positive social influence. Importantly, this effect went away in middle adolescence. Although adolescents are highly motivated to learn their parents' and peers' attitudes about externalizing behaviors, how much those attitudes inform their personal attitudes depends on the source of input and the age of adolescents.learning the attitudes of others (i.e., paid more) tended to shift their own attitudes more toward those endorsing positive influence, regardless of the source. In contrast, early adolescents who valued learning others' attitudes less were less susceptible to positive social influence. Importantly, this effectwent away inmiddle adolescence.Although adolescents are highly motivated to learn their parents' and peers' attitudes about externalizing behaviors, how much those attitudes inform their personal attitudes depends on the source of input and the age of adolescents (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Developmental changes in brain function linked with addiction-like social media use two years later.

Addiction-like social media use (ASMU) is widely reported among adolescents and is associated with depression and other negative health outcomes. We aimed to identify developmental trajectories of neural social feedback processing that are linked to higher levels of ASMU in later adolescence. Within a longitudinal design, 103 adolescents completed a social incentive delay task during 1-3 fMRI scans (6-9th grade), and a 4th self-report assessment of ASMU and depressive symptoms ∼2 years later (10-11th grade). We assessed ASMU effects on brain responsivity to positive social feedback across puberty and relationships between brain responsivity development, ASMU symptoms, and depressive symptoms while considering gender effects. Findings demonstrate decreasing responsivity, across puberty, in the ventral media prefrontal cortex, medial prefrontal cortex, posterior cingulate cortex, and right inferior frontal gyrus associated with higher ASMU symptoms over 2 years later. Significant moderated mediation models suggest that these pubertal decreases in brain responsivity are associated with increased ASMU symptoms which, among adolescent girls (but not boys), is in turn associated with increased depressive symptoms. Results suggest initial hyperresponsivity to positive social feedback, before puberty onset, and decreases in this response across development, may be risk factors for ASMU in later adolescence.

Dispositional and Social Correlates of Digital Status Seeking Among Adolescents.

Social media have transformed peer relationships among adolescents, providing new avenues to attain online status indicators such as likes and followers. This study aimed to explore the associations between various dispositional and social factors and digital status-seeking behaviors among a sample of adolescents (N = 731; Mage = 14.69, 48.7 percent female), as well as explore potential gender differences in the examined associations. Sociometric nominations for digital status-seeking, likeability, and popularity were collected, and participants self-reported their social media use frequency, awareness of social media positivity bias, reward sensitivity, and gender. The findings revealed a positive relationship between sociometric popularity and digital status-seeking, whereas likeability displayed a negative association with digital status-seeking. These results emphasize the importance of distinguishing between different social status indicators in understanding online behaviors. Reward sensitivity did not show a significant link to digital status-seeking, and awareness of social media positivity bias heightened the likelihood of being nominated as a digital status-seeker. These findings underscore the need for further research, especially focusing on girls who appear to be more vulnerable to engaging in digital status-seeking behaviors.

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.

Friendship changes differentially predict neural correlates of decision-making for friends across adolescence.

Adolescents' peer world is highly dynamic with constant dissolution of old friendships and formation of new ones. Though many of adolescents' risky decisions involve their peers, little is known about how adolescents' ever-changing friendships shape their ability to make these peer-involving risky decisions, particularly adaptive ones, and whether this association shifts over time. In a 5-wave longitudinal fMRI study, 173 adolescents (at wave 1: Mage = 12.8, SDage = 0.52; range = 11.9-14.5) made risky choices to win money for their best friend. We assessed whether participants nominated the same or different best friend as their previous participation year (a total of 340 data points of friendship maintenance / change). In early adolescence, adolescents with the same best friend took more adaptive risks for that best friend than those with a different best friend. In late adolescence, however, adolescents with a different best friend took more adaptive risks for the new best friend than those with the same best friend. Further, the amygdala was differentially sensitive to friendship maintenance / change during these peer-involving adaptive risks across time. This study has implications for how stable and flexible peer landscapes differentially modulate social motivation and social decision-making over the course of adolescence.

Why adolescents conform to high-status peers: Associations among conformity, identity alignment, and self-esteem.

This study examined whether conformity to high- but not low-status e-confederates was associated with increases in identification with popular peers and subsequent increases in self-esteem. A sample of 250 adolescents (55.1% male; Mage = 12.70 years; 40.3% White, 28.2% Black, 23.4% Hispanic/Latino, and 7.7% multiracial/other) participated in a well-established experimental chat room paradigm where they were exposed to norms communicated by high- and low-status e-confederates. Results revealed that for boys in the high-status condition only, but not girls, the positive relation between conformity and self-esteem was mediated by greater response alignment with popular peers. These findings bolster prior research by suggesting that conformity to popular peers may be partly motivated by drives for self-esteem and alignment with a valued reference group.

Telomere Erosion and Depressive Symptoms Across Development Following Institutional Care.

OBJECTIVE: A large literature has identified exposure to early caregiving adversities as a potent risk for developing affective psychopathology, with depression, in particular, increasing across childhood into adolescence. Evidence suggests telomere erosion, a marker of biological aging, may underlie associations between adverse early-life experiences and later depressive behavior; yet, little is understood about this association during development. METHOD: The current accelerated longitudinal study examined concurrent telomere length and depressive symptoms concurrently, 2 and 4 years later, from the preschool period through adolescence among children exposed (n =116) and not exposed (n = 242) to early previous institutional (PI) care. RESULTS: PI care was associated with shorter telomeres on average and with quadratic age-related growth in depressive symptoms, indicating a steeper association between PI care and depressive symptoms in younger age groups that leveled off in adolescence. Contrary to studies in adult samples, telomere length was not associated with depressive symptoms, and it did not predict future symptoms. CONCLUSION: These findings indicate that early caregiving disruptions increase the risk for both accelerated biological aging and depressive symptoms, although these variables did not correlate with each other during this age range.

Links Between Objectively-Measured Hourly Smartphone Use and Adolescent Wake Events Across Two Weeks.

PURPOSE: Psychosocial and bioregulatory pressures threaten sleep during adolescence. Although recent work suggests that the ubiquity of smartphone use throughout adolescence may also relate to poorer sleep outcomes, most existing research relies upon self-report and retrospective measures. This study drew upon objective measures of smartphone use and sleep at the hourly level to understand how smartphone use was associated with the duration of wake events during sleeping hours. METHODS: Across a 14-day daily study, 59 racially and ethnically diverse adolescents ages 15 to 18 had their sleep assessed via Fitbit Inspire 2 devices and uploaded screenshots of their screen time, pickups, and notifications as logged by their iPhone's iOS. Multi-level modeling was performed to assess hourly level associations between adolescent smartphone use and wake-events during their sleep sessions (N = 4,287 hourly cases). RESULTS: In hours during adolescents' sleep session with more screen time or pickups, adolescents had longer wake event duration. More notifications in a given hour were not associated with wake event duration in the same hour. CONCLUSIONS: Using objectively measured smartphone and sleep data collected at the hourly level, we found that during sleeping hours, when adolescents are actively engaging with their smartphones, their sleep is disrupted, such that their wake events are longer in that hour.

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.

Why Haven't You Texted Me Back? Adolescents' Digital Entrapment, Friendship Conflict, and Perceived General Health.

OBJECTIVE: Many adolescents feel pressure to be constantly available and responsive to others via their smartphones and social media. This phenomenon has been understudied using quantitative methods, and no prior study has examined adolescents' specific stress about meeting digital availability expectations within a best friendship, or entrapment. The present study offers an important preliminary examination of this unique digital stressor in a developmental context by examining prospective associations between digital entrapment, psychosocial adjustment, and health in adolescence. METHOD: Students in a rural, lower-income school district in the southeastern US (n = 714; 53.8% female; 45.9% White, 22.7% Black, 24.0% Hispanic/Latino) completed self-report measures of digital entrapment, perceived general health, friendship conflict, and depressive symptoms at two timepoints, one year apart. RESULTS: Digital entrapment, which 76.3% of the sample reported experiencing, was associated prospectively with higher levels of friendship conflict and worse perceived general health one year later among boys, but not girls. Findings suggest that digital entrapment is an extremely common experience for adolescents that may disproportionally affect boys. Entrapment was not prospectively associated with depressive symptoms. CONCLUSIONS: Results offer insight into how boys may have different social media experiences significant to their development and health, while much work exploring gender differences in social media use thus far has elucidated negative effects for girls. Boys may perceive and respond to novel social norms of digital environments differently such that digital entrapment has the potential to be detrimental to their friendships and health.

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.

Neural Representation of Donating Time and Money.

Volunteering and charitable donations are two common forms of prosocial behavior, yet it is unclear whether these other-benefitting behaviors are supported by the same or different neurobiological mechanisms. During an fMRI task, 40 participants (20 female-identifying; age: mean = 18.92 years, range = 18.32-19.92 years) contributed their time (in minutes) and money (in dollars) to a variety of local charities. With the maximum amount of time and money that participants could spend on these charities, they did not differentially donate their time and money. At the neural level, donating time and money both showed activations in brain regions involved in cognitive control (e.g., dorsolateral PFC) and affective processing (e.g., dorsal anterior cingulate cortex), but donating time recruited regions involved in reward valuation (e.g., ventral striatum) and mentalizing (e.g., temporal pole) to a greater extent than donating money. Further, the precuneus, which is also a region involved in mentalizing, more strongly tracked the varying amount of money than time donated, suggesting that the precuneus may be more sensitive to the increasing magnitude of a nonsocial exchange (e.g., donating money is a financial exchange) than a social exchange (e.g., donating time is an interpersonal exchange). Our findings elucidate shared as well as distinct neurobiological properties of two prosocial behaviors, which have implications for how humans share different resources to positively impact their community.SIGNIFICANCE STATEMENT Prosocial behaviors broadly characterize how humans act to benefit others. Various prosocial behaviors, such as volunteering and charitable donations, share the goal of positively contributing to community. Our study identifies brain regions that may serve as ubiquitous neurobiological markers of community-based prosocial behaviors. Despite this shared goal, our study also shows that the human brain responds to donating time and money in diverging ways, such that brain regions associated with processing emotional reward and thinking about others are more strongly recruited for donating time than for money. Therefore, our study sheds light on how different personal resources, such as one's time and money, within a prosocial context are represented in the brain.

Differential processing of risk and reward in delinquent and non-delinquent youth.

The present study examined the behavioral and neural differences in risky decision-making between delinquent (n = 23) and non-delinquent (n = 27) youth ages 13-17 years (M = 16, SD = 0.97) in relation to reward processing. While undergoing functional neuroimaging, participants completed an experimental risk task wherein they received feedback about the riskiness of their behavior in the form of facial expressions that morphed from happy to angry. Behavioral results indicated that delinquent youth took fewer risks and earned fewer rewards on the task than non-delinquent youth. Results from whole-brain analyses indicated no group differences in sensitivity to punishments (i.e. angry faces), but instead showed that delinquent youth evinced greater neural tracking of reward outcomes (i.e. cash-ins) in regions including the ventral striatum and inferior frontal gyrus. While behavioral results show that delinquent youth were more risk-averse, the neural results indicated that delinquent youth were also more reward-driven, potentially suggesting a preference for immediate rewards. Results offer important insights into differential decision-making processes between delinquent and non-delinquent youth.

Linking video chatting, phone calling, text messaging, and social media with peers to adolescent connectedness.

For 14 days three times per day (6072 observations), adolescents (N = 207, Mage = 15.45 years) reported their digital (i.e., video chatting, texting, social media, and phone calling) communication with peers and their social connectedness. Controlling for in-person interactions, adolescents felt more connected in hours when they had communicated with peers by video chatting, texting, or social media, but not phone calling. Girls communicated with peers via text and social media more than boys, and boys talked on the phone more than girls. Boys who talked, texted, or video chatted more on average reported higher connectedness on average, whereas girls did not. As the links with connectedness were only found at the hourly- and not the daily level, results highlight that a sense of connectedness from digital media may be fleeting in nature.

Corticostriatal Connectivity during Prosocial Decision-making Relates to Giving Behavior during Adolescence.

Prosocial behavior during adolescence becomes more differentiated based on the recipient of the action as well as the perceived value or benefit, relative to the cost to self, for the recipients. The current study investigated how functional connectivity of corticostriatal networks tracked the value of prosocial decisions as a function of target recipient (caregiver, friend, stranger) and age of the giver, and how they related to giving behavior. Two hundred sixty-one adolescents (9-15 and 19-20 years of age) completed a decision-making task in which they could give money to caregivers, friends, and strangers while undergoing fMRI. Results indicated that adolescents were more likely to give to others as the value of the prosocial decision (i.e., the difference between the benefit to other relative to the cost to self) increased; this effect was stronger for known (caregiver and friends) than unknown targets, and increased with age. Functional connectivity between the nucleus accumbens (NAcc) and OFC increased as the value of the prosocial decisions decreased for strangers, but not for known others, irrespective of choice. This differentiated NAcc-OFC functional connectivity during decision-making as a function of value and target also increased with age. Furthermore, regardless of age, individuals who evinced greater value-related NAcc-OFC functional connectivity when considering giving to strangers relative to known others showed smaller differentiated rates of giving between targets. These findings highlight the role of corticostriatal development in supporting the increasing complexity of prosocial development across adolescence.

Risk for Depressive Symptoms Among Adolescents with a History of Adversity: Unique Role of Stress Appraisals.

Lifetime social adversity predicts elevated depressive symptoms in adolescence. However, most adversity-exposed youth do not develop depression, highlighting the importance of examining risk and protective factors. The present study leveraged a multi-method approach, incorporating self-report, interview, and independent coding to examine whether appraisals of recent stressors moderate the effect of social adversity on depressive symptoms in 81 adolescent girls (Mage = 16.30 years, SD = .85). We utilized semi-structured interviews of lifetime adversity and recent stressors and semi-structured interviews and self-reports of depressive symptoms. Stress appraisals were calculated by regressing youths' subjective estimations of event stressfulness and dependence on estimations of independent coders. Lifetime social adversity predicted elevated depressive symptoms more strongly in girls who appraised interpersonal events as more stressful and dependent on their actions, providing insight into individual differences in depressive symptoms in adversity-exposed adolescents.

Neural similarity in nucleus accumbens during decision-making for the self and a best friend: Links to adolescents' self-reported susceptibility to peer influence and risk taking.

Adolescence is marked by increased peer influence on risk taking; however, recent literature suggests enormous individual variation in peer influence susceptibility to risk-taking behaviors. The current study uses representation similarity analysis to test whether neural similarity between decision-making for self and peers (i.e., best friends) in a risky context is associated with individual differences in self-reported peer influence susceptibility and risky behaviors in adolescents. Adolescent participants (N = 166, Mage = 12.89) completed a neuroimaging task in which they made risky decisions to receive rewards for themselves, their best friend, and their parents. Adolescent participants self-reported peer influence susceptibility and engagement in risk-taking behaviors. We found that adolescents with greater similarity in nucleus accumbens (NACC) response patterns between the self and their best friend reported greater susceptibility to peer influence and increased risk-taking behaviors. However, neural similarity in ventromedial prefrontal cortex (vmPFC) was not significantly associated with adolescents' peer influence susceptibility and risk-taking behaviors. Further, when examining neural similarity between adolescents' self and their parent in the NACC and vmPFC, we did not find links to peer influence susceptibility and risk-taking behaviors. Together, our results suggest that greater similarity for self and friend in the NACC is associated with individual differences in adolescents' peer influence susceptibility and risk-taking behaviors.

The Effect of Parents and Peers on the Neural Correlates of Risk Taking and Antisocial Behavior During Adolescence.

Social and neurobiological factors independently associate with the development of antisocial behavior during adolescence, yet it is unclear how these factors contribute to antisocial behavior in girls. Using a longitudinal sample of 45 adolescent girls (age in years at scan: M = 15.38, SD = 0.33), this study examined the contributions of parent-adolescent relationship quality and deviant peer affiliation from 6th-8th grades along with the neural correlates of risk taking in 9th grade to later antisocial behavior. High parent-adolescent closeness in early adolescence predicted lower antisocial behavior for girls in later adolescence via lower affiliation with deviant peer groups and less activation of the medial prefrontal cortex during risk taking. Findings highlight the enduring role of parents and peers during adolescence, and the importance of investigating social relationships alongside the brain to identify a holistic understanding of the development of antisocial behavior in girls.