Heartwarming: How Our Inner Thermostat Made Us Human

Ijzerman, an associate professor of social psychology at Université Grenoble Alpes, debuts with a scattershot study of the concept of social thermoregulation: the idea that social connections have a physiological benefit in maintaining a person’s core body temperature. Thermoregulation, he argues, “reconciles the divorce of mind from body by yielding a profound insight into what it means to be human,” further claiming that one’s psychology can influence physical temperatures and vice versa. Colloquialisms (calling people “warm” or “icy”) can influence human bodies as well, Ijzerman writes, and taking a warm cup of coffee from someone can “prompt an increased judgment of social warmth.” The effect of holding beverages reappears frequently in the studies recounted throughout, though Izjerman admits results have often been inconclusive or nonreplicable, and he writes that “only a single project exists to demonstrate a relationship between network diversity and human core body temperature.” Even with this acknowledgment, he overreaches, such as when he interprets modern competition for fuel sources as being primarily about thermoregulation, or suggests that in the near future people will be able to use thermoregulation to “improve the quality of their close relationships.” There is much that may prove intriguing to practitioners of psychology or to the interested layperson, but less that is truly convincing. (Feb.)