Perceptions of susceptibility to cancer or its severity are in part governed by beliefs about personal actions that mitigate or increase cancer risk. Ronis (1992) characterized conditional health threat as the perception of threat under some behavior specification, that is, if the individual were to take a specific protective health action versus to take no health action (see also Rogers, 1983). Ronis (1992) and van der Pligt (1998) argued that the measurement of conditional health threat would provide better understanding of protective health behavior because such conditional measures untangle the influence of current protective behavior on perceived vulnerability. Weinstein and Nicolich (1993) theorized that the discrepancy in level of perceived risk associated with participation versus nonparticipation in a health protective behavior reflected perceived effectiveness of the health precaution.
It is proposed that the components of conditional health threat-that is, conditional susceptibility versus conditional severity-will have differential associations with preventive versus screening behavior. For preventive behavior, high perceived susceptibility given inaction coupled with high perceived benefits of the health action is expected to produce preventive behavior, with a subsequent reduction in perceived susceptibility. For screening, the matter is different because susceptibility is not reduced by screening; rather, the argument for screening is that consequences (severity) of cancer will be reduced with early detection, so that the appropriate conditional characterizations of perceived severity are “severity if treated early” versus “severity if treated late” (Ronis & Hare& 1989). Ronis and Hare1 (1989) applied this dual conception of perceived severity to BSE performance and showed a link of these severity measures, but not conditional susceptibility, to BSE, yielding new insight into the potential role of perceived severity in screening. Jackson (1997) applied conditional perceived susceptibility and severity to skin cancer preventive behaviors and found the opposite effect-that conditional measures of perceived susceptibility, but not severity, predicted skin protection. Measures of conditional threat may provide help to clarify the links of perceived susceptibility and severity to cancer protective behaviors.
The impact of perceptions of risk on decisions concerning health behavior is strongly affected by the manner in which risks are framed. As specified in prospect theory (Kahneman & Tversky, 1979), individuals respond differently to information presented as gains (e.g., the number of breast cancer deaths averted by regular mammography screening) versus as losses (e.g., the number of breast cancer deaths associated with failures to be screened). Thus considerations of perceived risk in relation to cancer-related behavior must take into account message framing as a moderator of the perceived risk-behavior link. Rothman and Salovey (199'7) provided an extensive review of the impact of message framing on health behavior. Meyerowitz and Chaiken (1987), Rothman, Salovey, Antone, Keough, and Martin (1993), and Banks et al. (1995) provided examples of the impact of message framing on BSE, skin protection, and mammography utilization, respectively.
Variables like demographics, personality, and barriers to health action may moderate (change) the relation of perceived vulnerability to protective health behavior. High perceived barriers nullified the effect of susceptibility on mammography compliance (Aiken, West, Woodward, & Reno, 1994). Conscientiousness as a personality trait moderated the relation of cancer distress to mammography screening among FDRs of breast cancer victims (Schwartz, Taylor, et al., 1999). Moderation of the perceived susceptibility-behavior link by demographic, medical system, personality, and other psychosocial variables should be explored.
Our conception of perceived susceptibility is that it stands at the outset of a causal chain that flows through other constructs to health behavior. Consideration of mediational chains from perceived susceptibility through other variables to behavior is critical for advancing an understanding of the way health behaviors accrue. To reiterate, examination of both the direct effect and the indirect effects of susceptibility through other variables on behavior is required to estimate accurately the total effect of perceived susceptibility on health protective behavior.
The understanding of whether, how, and to what extent individual variables such as perceived susceptibility operate in determining health protective behavior is best advanced through the evaluation of model-based interventions, with research structured so that mediational analysis of the effects of putative determinants of behavior can be accomplished (West & Aiken, 1997). A distinguishing feature of psychology as a discipline is the strength in theory and experimentation. Thus, health psychologists may entertain a special role in health behavior research, providing careful theory testing in controlled settings, and the refinement of models of health behavior on a strong empirical base.
Aiken, L. S., Fenaughty, A. M., West, S. G., Johnson, J. J., & Luckett, T. L. (1995). Perceived determinants of risk for breast cancer and the relations among objective risk, perceived risk, and screening behavior over time. Women's Health: Research on Gender, Behavior, and Policy, 1, 27–50.
Aiken, L. S., Jackson, K. M., & Lapin, A. (1998). Mammography screening for women under 50: Women's response to medical controversy and changing practice guidelines. Women's He&h: Research on Gender, Behavior, and Policy, 4, 169–197.
Aiken, L. S., West, S. G., Woodward, C. IS., 6t Rena, R. R-(1994) Health beliefs and compliance with mammography-screening