Date of Award




Document Type


Degree Name

Doctor of Philosophy (PhD)


Department of Psychology


Behavioral Neuroscience

Content Description

1 online resource (viii, 82 pages) : illustrations (some color)

Dissertation/Thesis Chair

Kevin J Williams

Committee Members

Donn Byrne, Christine K Wagner


aggression, arousal, hostility to women, NSNE, Nipple (Anatomy), Body language, Aggressiveness

Subject Categories

Biological Psychology


Nipple erection in women for any purpose other than lactation is somewhat of an evolutionary mystery. In earlier studies I found evidence of nonsexual nipple erection (NSNE) in females in response to anxiety-provoking stimulus material (LeFevre, unpublished). The goal of the present research was to determine what benefits, if any, that NSNE may confer upon females who display this behavior. Specifically, two studies tested the general proposition that non-sexual nipple erection decreases aggressiveness in males and looked at the possibility that cognitive interference may be a mediating factor in aggression de-escalation. Fifty-one undergraduate students (33 male and 18 female) took part in a pilot study to identify appropriate stimulus material for subsequent studies. They viewed a PowerPoint presentation of 32 slides of models, photographed from the waist up, wearing white cotton t-shirts. Each model displayed 6 different emotions with and without nipple erection. Based on pilot study results, stimulus material was chosen for use in subsequent studies. Study 1 tested the hypotheses that males primed with stimuli of females showing NSNE will display lower aggression toward (Hypothesis 1) and be more forgiving (Hypothesis 2) of females who have committed an act against them). Sixty-eight male undergraduates took part in a study that looked at possible effects of nonsexual nipple erection on aggression. It was found that nonsexual nipple erection (NSNE) affects aggression and forgiveness tendencies in males in hypothetical situations where females have provoked the male either accidentally or purposely. In Study 2 I looked into cognitive interference as a possible mediating mechanism of the lowered aggression and increased forgiveness effects I found in Study 1. Specifically, I tested the hypotheses that because of cognitive interference, males, when provoked, will be less accurate at judging emotions (Hypothesis 3) and slower at judging emotions (Hypothesis 4). Eighty-nine undergraduate students (50 male and 39 female) took part in a reaction time study. However, in Study 2, we found little evidence of an effect of NSNE on ability to judge emotions. Thus, hypotheses 1 and 2 were supported, but Hypotheses 3 and 4 were not. Future research needs to examine other possible mediating factors responsible for the reduction in aggression and increase in forgiveness that occurs when provoked males are presented with NSNE as a stimulus.