307 Decision Psychology Time Preferences and Preventive Health Behavior: Acceptance of the Influenza Vaccine GRETCHEN B. CHAPMAN, PhD, ELLIOT J. COUPS Background. Many preventive health behaviors involve immediate costs and delayed benefits. Time preference is the extent to which decision makers value future outcomes relative to immediate ones. Consequently, people with future-oriented time preferences should be more likely to adopt preventive measures. The relationship between time preferences and acceptance of a free influenza vaccination was examined. Sample. The participants were 412 corporate employees who were offered free influenza vac- cinations at their workplace. Measures. Participants’ time preferences were measured in each of two domains: money and health. They also reported on whether they had accepted the influenza vaccination and their beliefs and attitudes about the vaccine. Results. There was a small (OR = 2.38) relationship of vaccination acceptance to monetary time preferences but not to the health time-preference measures. Other var- iables, such as perceived effectiveness of the vaccine, were more predictive. Conclu- sion. This study provides some evidence of a small relationship between time prefer- ences and preventive health behavior. Key words: time preference; decision making; preventive health behavior; influenza vaccine. (Med Decis Making 1999;19:307–314) One of the primary questions addressed by studies of health behavior is: why do people often fail to take preventive health measures? For example, why do people fail to adopt diets and exercise regimens that would reduce their risk of coronary heart disease? Why do people continue to smoke and use other hazardous substances? Why do people neglect to re- ceive recommended vaccinations? If we can better understand the underlying sources of such failings, we will be better equipped to ameliorate them. In an era of managed care and cost cutting, patients are being encouraged to take greater responsibility for their own health. Adopting preventive health be- haviors is a key component of that responsibility. One reason people may fail to take preventive measures is lack of relevant information. For ex- Received July 24, 1998, from the Psychology Department, Rut- gers University, Piscataway, New Jersey. Revision accepted for publication March 11, 1999. Supported in part by grant HS09519- 01 from the Agency for Health Care Policy and Research awarded to the first author. Address correspondence and reprint requests to Dr. Chap- man: Rutgers University, Psychology Department, Busch Cam- pus, 152 Frelinghuysen Road, Piscataway NJ 08854-8020; e-mail: gbc@ rci.rutgers.edu. ample, a person may eat a high-fat diet because he or she does not know that it is linked to heart dis- ease. A second reason is that people may not believe the information available to them: someone may continue to smoke because he or she does not be- lieve that it causes lung disease. A third reason for failing to engage in preventive behavior may be that people do not value the outcomes of the preventive behavior. Fo r example, someone may neglect to practice safe sex because the pleasures of unsafe sex are preferable to a lower risk of infectious disease. In terms of utility theory, belief corresponds to probability and value corresponds to utility. In ad- dition to the probability and utility of outcomes, util- ity theory also incorporates the timing of the out- comes of behavior. Fo r example, the costs of a low-fat diet begin immediately, in the form of re- fraining from eating favorite foods. The benefits, however, occur only later, because the cardiac events prevented would not have occurred until af- ter a delay. Discounted utility theory 1,2 incorporates delays by applying a temporal discount factor to de- layed outcomes. A positive discount rate reduces the value of delayed outcomes relative to immediate out- comes, while a negative discount rate reflects a greater value for delayed outcomes, and a zero dis-