This chapter looks at several types of explanation that can be applied to sexual desire and the links between them. It starts by considering desire in the here-and-now; that is, events in the mind and brain as individuals experience sexual desire. Some basic psychology and biology will then be introduced. The book suggests that we can gain insight by exploring similarities between sex and a number of other activities, for example feeding, gambling and drug-taking. The chapter then asks how the processes underlying sexual desire came into being. Two very different time scales will be considered: the evolutionary history of humans and the development of the individual.

The ‘here-and-now’: broad principles

The study of desire in the here-and-now is in terms of brains and minds, as well as such things as heart rate and blood flow to the genitals. Of course, desire is often triggered by the perception of an attractive person. This much would be obvious simply from talking to the one feeling the desire, quite apart from monitoring events in the body and observing behaviour. In the physical absence of an attractive other, representations of such an individual in the form of pictures or simply memories in the mind can trigger desire. Sensations arising in the genitals also contribute to desire and lock into interaction with the factors just described.