A multi-modal investigation of reward-based mechanisms underlying excessive and problematic social networking site use

Abstract

The use of social networking sites (SNSs) has become a universally popular activity, but there also exists widespread concerns regarding the harmful consequences associated with SNS overuse, including the potential for addiction. Nonetheless, the extent to which a ‘SNS addiction’ represents a valid psychiatric disorder is still controversially discussed in the scientific literature. The present thesis sought to better understand excessive and problematic SNS use behaviours by assessing the underlying reward-based mechanisms using a range of measurement modalities (i.e., self-report, implicit behavioural, psychophysiological, and neural). Chapter two demonstrated the utility of reward-related motives in predicting problematic SNS use behaviours, with motives related to social reward (e.g., obtaining ‘likes’) being the strongest predictor of more harmful use. Chapter three assessed explicit and implicit motivational responses to SNS stimuli but found no clear evidence of altered explicit cue reactivity or automatic action tendencies in more problematic SNS users. Chapter four tracked changes in affective and motivational responses during a week of restricted SNS use, however findings revealed no substantial impact on mood or cravings in both regular and problematic users. Chapter five investigated the effect of brief periods of SNS use and subsequent use cessation on heart rate and skin conductance. While SNS use and cessation were associated with distinct physiological changes, these effects were experienced ubiquitously and could not differentiate problematic users from regular users. Chapter 6 systematically reviewed the MRI literature for evidence of neural abnormalities associated with SNS use. Some neural similarities with substance use addictions were identified, but existing research was scarce and findings across studies were largely inconsistent. Taken together, we did not find convincing evidence of a distinct cognitive, behavioural, or physiological profile in problematic SNS users. Therefore, the present thesis argues that conceptualising excessive or problematic SNS use as a new behavioural addiction would be premature. It is clear that SNS use is a highly rewarding and engaging activity that can be overused with negative effects, but equating this behaviour to conditions such as alcohol, cocaine, and heroin disorders risks trivialising the field of addiction research.