Negative ions and behavior: impact on mood, memory, and aggression among type A and type B persons

Individuals scoring high (Type As), intermediate, or low (Type Bs) on the Jenkins Activity Survey were given an opportunity to aggress against a stranger who, previously, had either provoked or not provoked them. The opportunity to aggress (as well as all other aspects of the study) took place in the presence of (a) a high concentration, (b) a moderate concentration, or (c) a low (ambient) concentration of negative air ions. Results indicated that exposure to moderate or high levels of negative ions significantly enhanced aggression by Type A subjects, but not by other participants. In addition, we found that negative ions produced positive shifts in subjects' reported moods in the absence of provocation, but negative shifts in moods in the presence of provocation. These findings suggest that moderate or high concentrations of negative ions serve as a source of heightened activation, thus enhancing individuals' dominant reactions or tendencies in a given situation.