When people are forced to be isolated from one another, do they crave social interactions in the same way a hungry person craves food? Positive social interactions in and of themselves may be basic human needs, analogous to other basic needs like food consumption or sleep. If so, the absence of positive social interaction may create a want, or "craving", that motivates behavior to repair what is lacking. In the mouse model, even a brief acute period of social isolation causes an aversive, ‘loneliness-like’ brain state causing the mice to seek social interaction which is mediated specifically by dopaminergic midbrain neurons (Matthews et al. 2016), similar to other kinds of craving. However, the homology to human loneliness has been disputed, and it is not possible to assess whether a mouse subjectively feels lonely. Would acute isolation evoke a similar response in humans? To address this question, we used functional magnetic resonance imaging (fMRI) to measure neural responses in participants (n=40) evoked by food and social cues after ten hours of mandated fasting or total social isolation. After isolation, people felt lonely and craved social interaction. Midbrain regions showed increased activation to food cues after fasting and to social cues after isolation; these responses were correlated with self-reported craving. Neural patterns in response to food cues when participants were hungry generalized to social cues after isolation. Our results support the intuitive idea that acute isolation causes social craving, similar to hunger.

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