Experiencing acceptance or rejection when communicating via digital media is an impactful social experience. Extensive research, including large meta-analyses, has demonstrated that social rejection in a computerized environment can be experienced similarly as face-to-face rejection and bullying, although the prevalence of cyberbullying is generally lower22,23 (and studies vary widely: prevalence rates depend on how cyberbullying is defined and measured). In all, cyberbullying peaks during adolescence24 and large overlap has been found between victims and bullies. In part, this overlap could be explained by victimized adolescents seeking exposure to antisocial and risk behavior media content25. The next subsections will describe recent discoveries in neuroscience on the neural responses to online rejection and acceptance.

Neural responses to online social rejection

The emotional and neural effects of being socially excluded have been well captured by research involving the Cyberball Paradigm26 (https://cyberball.wikispaces.com/). Cyberball is a virtual ball-toss game in which the study participant tosses a ball with two simulated players (so-called confederates) via a screen. After a round of fair play, the confederates, who only throw the ball to each other, exclude the participant in the rejection condition. This results in pronounced negative effects on the participants’ feeling to belong, ostracism, sense of control, and self-esteem26. Even though the paradigm was not designed to study online rejection as it occurs today on social media, the findings of prior Cyberball studies may provide an important starting point for understanding the processes involved in online rejection. In fact, inspired by Cyberball, a Social Media Ostracism paradigm has recently been developed by applying a Facebook format to study the effects of online social exclusion27.

Using functional MRI (fMRI), researchers have observed increased activity in the orbitofrontal cortex and insula after participants experienced exclusion, possibly signaling increased arousal and negative affect28. In addition, stronger activity in the dorsal anterior cingulate cortex (ACC) is observed in adolescents and young adults with a history of being socially excluded29, maltreated30, or insecure attachment, whereas spending more time with friends reduced ACC response in adolescents to social exclusion31. This may possibly protect adolescents against the negative influence of ostracism or cyberbullying, although all these studies are correlational. Therefore, it remains to be determined whether environment influences brain development or vice versa. Moreover, ACC and insula activity have also been explained as signaling a highly significant event because the same regions are also active when participants experience inclusion32. Furthermore, studies with adolescents observed specific activity in the ventral striatum33, and in the subgenual ACC when adolescents were excluded in the online Cyberball computer game34,35, the latter region is often implicated in depression36. Thus, being rejected was associated with activity in brain regions that are also activated when experiencing salient emotions37,38. These studies may indicate a specific window of sensitivity to social rejection in adolescence, which may be associated with the enhanced activity of striatum and subgenual ACC in adolescence33,36.

Social rejection has also been studied using task paradigms that mirror online communication more specifically. In the social judgment paradigm, participants enter a chat room, where others can judge their profile pictures based on first impression39. This can result in being rejected or accepted by others in a way that is directly comparable to social media environments where individuals connect based on first impression (for example,’liking’ on Instagram). A developmental behavioral study (participants between 10 and 23 years) showed that young adults expected to be accepted more than adolescents. Moreover, these adults, relative to adolescents, adjusted their evaluations of others more based on whether others accepted or rejected them, possibly indicating self-protecting biases40 (Fig. 2). Neuroimaging studies revealed that, being rejected based only on one’s profile pictures resulted in increased activity in the medial frontal cortex, in both adults41 and children42, and studies in adolescents showed enhanced pupil dilation, a response to greater cognitive load and emotional intensity, to rejection43.

Fig. 2 Adolescents’ expectations and adjustments of being liked and liking others. Social evaluation study in which participants between ages 10 and 23 years rated other peers on whether they liked the other person, whether they believed the other would like them, and a post scan rating of liking the other person after having received acceptance or rejection feedback from the other person. The faces used in this adaptation of figure are cartoon approximations of the original stimuli used in ref. 40; to see the original stimuli, please refer to ref. 40. The left graph shows that adolescents expect least to be liked by the other before receiving feedback (question B). The right graph shows a developmental increase in distinguishing between liking and disliking based on feedback from the other person (question D). (Adapted with permission from Rodman, 2017, PNAS40) Full size image

Taken together, these studies suggest that adolescents show stronger rejection expectation than adults, and subgenual ACC and medial frontal cortex are critically involved when processing online exclusion or rejection. In the next section, we describe how the brain of adolescents and adults respond to receiving positive feedback and likes from others.

Neural responses to online social acceptance

The positive feeling of social acceptance online is endorsed through the receipt of likes, one’s cool ratio (i.e., followers > following; Business Insider, 11 June 2014: http://www.businessinsider.com/instagram-cool-ratio-2014–6?international=true&r=US&IR=T.) or popularity, positive comments and hashtags, among other forms of reward44,45. Neuropsychological research showed that being accepted evokes activation in similar brain regions, as when receiving other rewards such as money or pleasant tastes38. Most pronounced activity was found in the ventral striatum, together with the ventromedial prefrontal cortex and ventral tegmental area, which is consistently reported as a key region in the brain for the subjective experience of pleasure and reward46, including social rewards47. Likewise, being socially accepted through likes in the chat room task resulted in increased activity in the ventral striatum in children42, adolescents48,49 and adults41,50. This response is blunted in adolescents who experience depression36, or who have experienced a history of maternal negative affect51. Apparently, prior social experiences—such as parental relations—are an important factor for understanding which adolescents are more sensitive to the impact of social media51. In this regard, media research showed that popularity moderates depression10 and that attachment styles and loneliness increases the likelihood to seek socio-affective bonding with media figures52.

Interestingly, several studies and meta-analyses using gambling and reward paradigms have reported that activity in the ventral striatum to monetary rewards peaks in mid-adolescence53,54,55 (Fig. 3; see Box 1 for views on adolescent risk taking in various contexts). These findings may suggest general reward sensitivity in adolescence such that reward centers that respond to monetary reward may also show increased sensitivity to social reward in adolescence. Social reward sensitivity may be a strong reinforcer in social media use. A prior study in adults showed that activity in the ventral striatum in response to an increase in one’s reputation, but not wealth, predicted frequency of Facebook use56. In a similar vein, adolescents showed sensitivity to “likes” of peers on social media44,57. In a controlled experimental study, adolescents showed more activity in the ventral striatum when viewing images with many vs. few likes, and this activation was stronger for older adolescents and college students compared to younger adolescents57. Thus, the same region that is active when being liked on the basis of first impression of a profile picture48, is also activated when viewing images that are liked by others, especially in mid-to-late adolescence, possibly extending into adulthood57 (see also ref. 58 for similar findings on music preference). These findings suggest that heightened reward sensitivity in mid-adolescence that was previously observed for monetary rewards53 may also be present for social rewards such as likes on Instagram. However, further research is needed to examine whether this is a specific sensitivity in early, mid or late adolescence, or perhaps this social reward sensitivity emerges in adolescence and remains in adulthood.