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Habitually checking social media may be associated with changes in the brain's sensitivity to social rewards and punishments in preteens, according to an imaging-based study.

Young adolescents who checked in to Facebook, Instagram, or Snapchat at least 15 times per day also showed distinct longitudinal changes in their functional brain development, reported Eva H. Telzer, PhD, of the University of North Carolina at Chapel Hill, and colleagues in .

"These teens might become more attuned to social rewards or punishments including those in digital forms such as 'likes,' notifications, or comments," Telzer told 番茄社区. "Meanwhile, teens who do not check social media as often become less sensitive or attuned to social feedback over time."

"This increasing sensitivity to social information in teens who habitually check social media might prompt future compulsive social media checking. However, importantly, it may also be adaptive by helping them navigate social interactions in their increasingly digital worlds," Telzer added.

She emphasized that this research was focused on the behavior of children, who were recruited at age 12 to 13 years, so the specific social media site was not particularly important. She noted that an individual's behaviors are common across all platforms, so these results would likely be applicable to other social media sites or even new platforms that have not become widely used yet.

Telzer highlighted that a key study limitation was that the difference in sensitivity to social feedback was different at baseline between the children who habitually checked social media and the ones who did not.

"Teens who habitually checked started out less sensitive to social information, and became more sensitive over time, and teens who checked less often started out more sensitive and became less sensitive over time," she explained. "Because of this, we cannot determine if teens' social media use before the study caused these developmental differences."

"Nonetheless, differing social media behaviors were associated with different trajectories of brain development," Telzer added, noting that more research will be needed to help determine the social and emotional impact those differences have on a child.

The authors recruited 169 sixth and seventh graders from three public middle schools in rural North Carolina. Participants had a mean age of 13 years, and a majority were female (53.8%). A little more than a third (35.5%) were Latinx, 29.6% were white, 22.5% were Black, and 8.9% were multiracial.

The cohort was evaluated in several different areas, including a self-report on their behavior toward checking Facebook, Instagram, and Snapchat. They also participated in a task that measured neural responses when anticipating a social reward or punishment based on a timed task while being monitored using functional MRI.

Telzer noted that the behaviors seen in the study were not specific to one kind of social media or even one mode of influence, such as mobile notifications that prompt engagement with a certain platform.

"By focusing on behaviors which are common across all social media platforms, the results of the study are likely to be applicable to future social media platforms as technology continues to rapidly develop," she said.

The 3-year longitudinal cohort study demonstrated that habitual checking of social media was associated with lower neural sensitivity to social anticipation compared to non-habitual behavior related to social media for these students. These changes were shown in the:

• Left amygdala, posterior insula (PI), and ventral striatum (VS): β= -0.22 (95% CI -0.33 to -0.11)
• Right amygdala: β= -0.19 (95% CI -0.30 to -0.08)
• Right anterior insula (AI): β= -0.23 (95% CI -0.37 to -0.09)
• Left dorsolateral prefrontal cortex (DLPFC): β= -0.29 (95% CI -0.44 to -0.14)

The researchers also found that habitual checking of social media was linked with longitudinal increases in neural sensitivity in the:

• Left amygdala, PI, and VS: β=0.11 (95% CI 0.04-0.18)
• Right amygdala: β=0.09 (95% CI 0.02-0.16)
• Right AI: β=0.15 (95% CI 0.02-0.20)
• Left DLPFC: β=0.19 (95% CI 0.05-0.25)

However, the students who did not habitually check social media experienced longitudinal decreases in the left amygdala, PI, and VS (β= -0.12, 95% CI -0.19 to -0.06), right amygdala (β= -0.10, 95% CI -0.17 to -0.03), right AI (β= -0.13, 95% CI -0.22 to -0.04), and left DLPFC (β= -0.10, 95% CI -0.22 to -0.03).

Telzer and colleagues noted that "[t]wo primary theories contend over whether hypo- or hyperresponsivity to rewards is more associated with behavior," with the former potentially promoting "high-reward behaviors," while the latter "may be associated with a deficit in the activity of brain regions associated with motivation."

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