Given the amounts of money, time and energy that are currently being invested in the area as a result of the AIDS epidemic, it is essential to have an adequate conceptual framework with which to approach the understanding of sexual behaviour. This is not only a necessity for science to advance, but is also urgently required if relevant and effective interventions to reduce the spread of HIV infection are to be implemented. The aim of this chapter is to share our concerns regarding the application of traditional, cognitive health and social behaviour models to the study of sexual activity. Our target is the range of formal quantitatively based models that have been developed over the past twenty or so years to attempt to predict health-related behaviours. Starting with the Health Belief Model (Maiman and Becker, 1974; Rosenstock, 1974; Rosenstock, Stecher and Becker, 1988), various additions and adaptations have been made as different researchers have identified further components. Traditional social psychological models (Ajzen, 1985; Ajzen and Fishbein, 1980; Rogers, 1983) have also been applied in the context of health-

related behaviours and sexual activity. The underlying concept of individual rational decision-making that is implicit in these models has come under close scrutiny in recent years (Brown, DiClemente and Reynolds, 1991; Ingham, Woodcock and Stenner, 1992; Loewenstein and Furstenburg, 1991; Montgomery, et al., 1989; Pollak and Moatti, 1989; van Zessen and Straver, 1991). We are not concerned in this chapter about the utility of these models as such, but rather their specific application and operationalization in the field of sexual behaviour.