In his latest study, Berger measured how various emotional and physical stimuli designed to activate the autonomic nervous system affected the likelihood that subjects would share emotion-free news articles. In one experiment, he primed 93 respondents with pre-tested video clips to produce emotional states associated with high arousal (anxiety, amusement) and low arousal (sadness, contentment). Then, in what participants were told was an unrelated trial, Berger presented the respondents with neutral articles and videos, and asked them to rate how inclined they were to share these news items with friends, family members, and coworkers. The result: "Situations that heighten arousal boost social transmission," Berger concludes.