Paper Type

Master's Thesis


College of Arts and Sciences

Degree Name

Master of Science in Psychological Science (MSPS)



NACO controlled Corporate Body

University of North Florida. Department of Psychology

First Advisor

Dr. Lori Lange

Second Advisor

Dr. Dong-Yuan Wang

Department Chair

Dr. Lori Lange

College Dean

Dr. George Rainbolt


When the body is faced with threat to life or limb, the autonomic nervous system works to overcome the danger – by either fight, flight, or freezing. While immobility may not appear to be the most logical solution, theories exist that it allows for judgement of the situation and preparation for action. This study investigated the stress response that military veterans, with or without post-traumatic stress disorder (PTSD), demonstrate when shown unpleasant images. Researchers wanted to determine the extent to which veterans would show freezing or immobile responses when under an unpleasant image condition. It was hypothesized that veterans who report more traumatic experiences in their lifetime would move less and have a faster heart rate than veterans with fewer traumatic experiences. It was also predicted that veterans with higher severity of PTSD symptoms would stand more still and have a faster heart rate than veterans with lower severity. This research employed the use of a survey, heart rate monitor, and unpleasant images to measure trauma, PTSD, heart rate, and body sway. Thirty-eight military service member and veteran students from the University of North Florida were recruited and compensated for their participation. Body sway and heart rate variation across trauma and PTSD scores was found to be insignificant and unsupportive of the hypotheses. Among relations between military demographic variables and trauma and PTSD, several strong effect sizes were found. The small sample size severely limited the investigation’s