UC Santa Barbara

Every week approximately 57 million adults in the United States take a dose of acetaminophen, and another 42 million take a dose of ibuprofen. These medications – commonly known by the brand-names Tylenol and Advil – are taken with the intent to reduce fever, pain, and inflammation. Recent research has shown that these drugs also have dampening effects on perceptions of social pain, and not just physical pain. In addition, acetaminophen has produced a “blunting” effect on the strength of affective evaluations of stimuli: aversive noise stimuli, and both negative and positive visual stimuli. The current study investigates acetaminophen and ibuprofen’s effects on ingroup positivity in a minimal group context, specifically addressing the visual representations of the faces of ingroup versus outgroup members. Our hypothesis is that mental representations of ingroup member faces should be evaluated less positively under the affective blunting influence of acetaminophen. Our study failed to show the predicted blunting effect of acetaminophen on evaluations of representations of ingroup and outgroup members and instead showed the opposite pattern: increased ingroup positivity. Ibuprofen likewise produced representations of ingroup members that garnered greater ratings of ingroup positivity. Our study also included tasks designed to evaluate these medications’ effects on two potential psychological mechanisms underlying the main experimental task: affective evaluations and visual cognition. While the White Noise Evaluation revealed the predicted affective blunting effects of acetaminophen compared to placebo, the Mental Rotation Task for visual cognition skill revealed blunted performance for acetaminophen only as compared to ibuprofen.