Journal of Personality and Social Psychology 1978, Vol. 36, No. 11, 1213-1220 Reported Physical Symptoms Elicited by Unpredictable Events and the Type A Coronary-Prone Behavior Pattern Gerdi Weidner and Karen A. Matthews Kansas State University Unpredictable and uncontrollable events are associated with a variety of illnesses. It was hypothesized that unpredictable aversive events are causally linked to physical symptom reporting and that the Type A coronary-prone behavior pat- tern affects symptom reporting, such that Type A individuals fail to report symptoms when they expect to continue working on a task as compared to when they believe they have completed it. In the present research, Type A and Type B women reported symptoms either at the end or in the middle of listening to unpredictable, predictable, or ambient noise in the laboratory. Results showed that unpredictable noise produced more symptom reporting than predictable noise, which in turn produced more symptom reporting than the ambient noise; Type A individuals reported fewer symptoms in the middle of the task than at the end, whereas Type B's did not show this differential effect. Thus, both hy- potheses were confirmed. Several possible explanations of the results are offered, and implications of the findings are discussed. Unpredictable and uncontrollable events are associated with such negative states in humans as depression (e.g., Paykel et al., 1969), self- reported tension and distress (e.g., Vinokur & Selzer, 1975), and accidental injuries (Bram- well, Masuda, Wagner, & Holmes, 1975), as well as major illnesses such as coronary heart disease (e.g., Glass, 1977a). Unpredictable aversive events are less preferable than pre- dictable ones (e.g., Maltzman & Wolff, 1970; Pervin, 1963). An effective method of reduc- ing discomfort in a stressful environment is to increase predictability of the stress by provid- ing information (e.g., Langer & Saegert, This article is based on a master's thesis by the first author, under the direction of the second author, submitted to the Department of Psychology, Kansas State University. The research was funded by a grant from the Bureau of General Research, Kansas State University, to the second author. The authors would like to thank Sue Buckwald and Whitney Hummer for their able assistance as experimenters, Judy An- drews for analyzing the data, and Audrey Burnam, David Krantz, and James Pennebaker for their crit- ical comments on an earlier form of the manuscript. Requests for reprints should be sent to Karen A. Matthews, who is now at the Department of Psy- chiatry, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, Pennsylvania 15261. 1977). In animals, unpredictable shock results in stomach ulceration, elevated plasma corti- sone levels, and changes in body weight and body temperature (Weiss, 1970). Although there is direct evidence that uncontrollable events can cause reports of physical symptoms by humans (Pennebaker, Burnam, Schaeffer, & Harper, 1977), there is only indirect evi- dence for humans that unpredictable events do so. The present research tests the hypoth- esis that unpredictable aversive events elicit a greater degree of reported physical symptoms than predictable ones. According to Penne- baker et al. (1977), physical symptoms are denned as self-reports of somatic ailments that occur frequently in the normal popula- tion. Note that self-reports may differ from either experienced symptoms or physiological indexes of ailments. Symptom reporting is studied in the present investigation because of its importance to seeking medical care and to doctor-patient communication. Recent research has suggested that a coro- nary-prone behavior pattern called Type A af- fects the reporting of physical symptoms. Type A behavior is characterized by excesses of competitive achievement striving, time Copyright 1978 by the American Psychological Association, Inc. 0022-3514/78/3611-1213$00.75 1213