Patients frequently come to health care settings accompanied by trusted family members or friends, not only for psychological support but also to help them organize and recall information and think through important decisions. Typically, these social influences have been considered as either promoting or restricting an individual's own perceptions, cognitive processing, and emotions. Research now suggests that mental processes as diverse as perception, problem recognition, problem solving, and deciding about important issues may not be the result of cognitive processes solely within the mind of one individual. Rather, these processes are shared in some way across the cognitive and affective schemas of two or more individuals—sometimes to the point that no single individual can fully “own” the resulting perspective, preference, or choice.

These shared interpersonal processes, ...