Previous research has repeatedly shown that writing about an important value, compared with writing about an unimportant value, reduces defensiveness in response to self-threatening information, but has not identified why. Study 1 showed that participants who wrote about an important value reported more positive other-directed feelings, such as love and connection, than participants who wrote about an unimportant value. Study 2 replicated this effect, and showed that loving and connected feelings, but not positive or negative self-directed feelings, completely accounted for the effect of a values-affirmation manipulation on smokers' acceptance of information indicating that smoking harms health. These studies, in concert with previous research, suggest that values affirmation reduces defensiveness via self-transcendence, rather than self-integrity (i.e., self-worth or self-images).

Simulation theories of empathy hypothesize that empathizing with others' pain shares some common psychological computations with the processing of one's own pain. Support for this perspective has largely relied on functional neuroimaging evidence of an overlap between activations during the experience of physical pain and empathy for other people's pain. Here, we extend the functional overlap perspective to the neurochemical level and test whether a common physical painkiller, acetaminophen (paracetamol), can reduce empathy for another's pain. In two double-blind placebocontrolled experiments, participants rated perceived pain, personal distress and empathic concern in response to reading scenarios about another's physical or social pain, witnessing ostracism in the lab, or visualizing another study participant receiving painful noise blasts. As hypothesized, acetaminophen reduced empathy in response to others' pain. Acetaminophen also reduced the unpleasantness of noise blasts delivered to the participant, which mediated acetaminophen's effects on empathy. Together, these findings suggest that the physical painkiller acetaminophen reduces empathy for pain and provide a new perspective on the neurochemical bases of empathy. Because empathy regulates prosocial and antisocial behavior, these drug-induced reductions in empathy raise concerns about the broader social side effects of acetaminophen, which is taken by almost a quarter of adults in the United States each week.

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Nociception reliably elicits an autonomic nervous system (ANS) response. Because pain and ANS circuitry interact on multiple spinal, subcortical, and cortical levels, it remains unclear whether autonomic responses are simply a reflexive product of noxious stimulation regardless of how stimulation is consciously perceived or whether the experience of pain mediates ANS responses to noxious stimulation. To test these alternative predictions, we examined the relative contribution of noxious stimulation and individual pain experience to ANS responses in healthy volunteers who underwent 1 or 2 pain assessment tasks. Participants received 8 seconds of thermal stimulation of varied temperatures and judged pain intensity on every trial. Skin conductance responses and pupil dilation responses to stimulation served as measures of the heat-evoked autonomic response. We used multilevel modelling to examine trial-by-trial relationships between heat, pain, and ANS response. Although both pain and noxious heat stimulation predicted skin conductance response and pupil dilation response in separate analyses, the individual pain experience statistically mediated effects of noxious heat on both outcomes. Furthermore, moderated mediation revealed that evidence for this process was stronger when stimulation was perceived as painful compared with when stimulation was perceived as nonpainful, although this difference emerged late, in the 4-second period after thermal stimulation. These findings suggest that pain appraisal regulates the heat-evoked autonomic response to noxious stimulation, documenting the flexibility of the autonomic pain response to adjust to perceived or actual changes in environmental affordances above and beyond nociceptive input.