Seasonal changes in rule infractions among prisoners: a preliminary test of the temperature-aggression hypothesis

To test the temperature-aggression hypothesis, seasonal changes in aggression as indexed by reported rule infractions were studied for prisoners located at the Patuxent Institution, Jessup, Maryland. 5383 reports of rule infractions occurred between July 1987 and March 1991. Rule infractions occurred more frequently during the hot summer months than the three other seasons of the year. This summer effect, though significant, is only a few percent above a theoretical chance level based on the number of days comprising the seasons. A much stronger monthly effect over 45 months was found, but the bases of erratic fluctuations are not known.