Obesity among children and adolescents has dramatically increased over the past two to three decades and is now a major public health issue. During this same period, youth exposure to media devices also became increasingly prevalent. Here, we present the novel hypothesis that media multitasking (MMT)-the simultaneous use of and switching between unrelated forms of digital media-is associated with an imbalance between regulatory processes and reward-related responses to appetitive food stimuli, resulting in a greater sensitivity to external food cues among high media multitaskers. This, in turn, may contribute to overeating and weight gain over time. To test this hypothesis, we conducted two studies examining research participants who grew up during the recent period of escalating multitasking and obesity-and among whom 37% are overweight or obese. In Study 1, participants' propensity to engage in MMT behaviors was associated with a higher risk for obesity (as indicated by higher body mass index and body fat percentage). Next, in Study 2, a subset of participants from Study 1 were exposed to appetitive food cues while undergoing functional neuroimaging and then, using passive mobile sensing, the time participants spent in various food points-of-sale over an academic term was inferred from GPS coordinates of their mobile device. Study 2 revealed that MMT was associated with an altered pattern of brain activity in response to appetizing food cues, specifically an imbalance favoring reward-related activity in ventral striatum and orbitofrontal cortex-relative to recruitment of the frontoparietal control network. This relationship was further tested in a mediation model, whereby increased MMT, via a brain imbalance favoring reward over control, was associated with greater time spent in campus eateries. Taken together, findings from both studies suggest the possibility that media multitasking may be implicated in the recent obesity epidemic.
Keywords: Cue reactivity; Media multitasking; Obesity; Reward; Self-control failure.