Hot temperatures make people moody, less helpful

control group, they were more fatigued, which reduced their positive affect and, ultimately, pro-social behavior, researchers said.

Only 34 percent of the participants who were asked to recall a time when they were uncomfortably hot were willing to help with the free survey, compared to 76 percent in the control group.

Researchers also noted that recalling being uncomfortably hot also increased the negative affectivity, but it did not have any impact on pro-social behavior,