PII S0145-2134(98)00055-6 GENDER DIFFERENCES IN PHYSIOLOGICAL REACTIVITY TO INFANT CRIES AND SMILES IN MILITARY FAMILIES ALBERT L. BREWSTER AND JOHN P. NELSON Headquarters, Family Advocacy Program, Brooks Air Force Base, San Antonio, TX, USA THOMAS R. MCCANNE, D. R. LUCAS, AND JOEL S. MILNER Department of Psychology, Northern Illinois University, DeKalb, IL, USA ABSTRACT Objective: The primary purpose of this experiment was to examine gender differences in physiological reactivity to infant cries and smiles in military families. Method: Twenty males and 29 females viewed and listened to videotapes of a crying infant and a smiling infant while heart rate, skin resistance, and respiration rate were monitored. All participants were active-duty U.S. Air Force personnel or their spouses. Results: Males showed a larger increase in skin conductance than females during the crying infant stimulus. Males also showed an increase in heart rate during the crying infant stimulus, whereas females did not show any increase in heart rate during the crying infant stimulus. No gender differences in physiological reactivity were obtained during the smiling infant stimulus, although both males and females showed a significant increase in heart rate while viewing the smiling infant. Conclusions: The results are contrasted with previous reports (e.g., Frodi, Lamb, Leavitt, & Donovan, 1978) of no differences between genders in physiological reactivity to a crying infant. Discussion of the results focuses on models of child physical abuse that involve physiological hyperreactivity. It is hypothesized that the greater physiological reactivity of males than females during a crying infant videotape may partially explain why physical abuse of a child by a male frequently results in more serious damage to the child than physical abuse by a female. © 1998 Elsevier Science Ltd Key Words—Gender differences, Physiological reactivity, Child physical abuse, Military families. INTRODUCTION IN 1978, KNUTSON called attention to the physiological reactions of child physical abusers by suggesting that one factor contributing to child physical abuse is irritable aggression (Knutson, 1978, p. 20). Knutson argued that child physical abusers possess a hyperreactive (p. 23) trait that predisposes the abuser to be overly reactive to noxious social stimuli, especially the aversive behaviors associated with rearing children. Knutson suggested that irritable aggression is primarily a classically conditioned response, in contrast to instrumental aggression, which is primarily controlled by operant reinforcement. Research by Bauer and Twentyman (1985) also suggested that there may be differences in physiological reactions to child-related stimuli in child physical abusers Received for publication June 27, 1997; final revision received January 21, 1998; accepted January 22, 1998. Reprint requests should be addressed to Thomas R. McCanne, Department of Psychology, Northern Illinois University, DeKalb, IL 60115. Pergamon Child Abuse & Neglect, Vol. 22, No. 8, pp. 775–788, 1998 Copyright © 1998 Elsevier Science Ltd Printed in the USA. All rights reserved 0145-2134/98 $19.00 + .00 775