Sexual desire, the drive towards sex, mating or the feeling of ‘lust,’ is also a natural reward, or appetite, driven by the neurochemical dopamine. In this context dopamine stimulates the ‘anticipation’ of reward, the desire and wanting. Its main function is to encourage us to have babies, whether we actually want to have a baby or not, when we are making love.
Nature has a very clear and powerful agenda – to get those genes into the next generation. It thrives on genetic variety. The reason for this is to strengthen the gene pool. Inbreeding causes genetic defects and health concerns. This is a problem in many cultures where marrying first cousins is the norm. Having genetic variety means that if there is an epidemic of disease or other radical changes in living conditions, there is more likelihood that some individuals will have a mix of genes that will allow them to survive.
Orgasm, the intense sensation of pleasure that for many is the goal of the sexual act, sets off a cascade of neurochemicals, opioids, that we experience as euphoria. At that point the dopamine stops being pumped into the reward pathway. Any leftover is recycled back into the system ready for the next opportunity to drive us to a survival goal, the present one having been achieved.
The desire to feel the sensation of intense pleasure drives us to repeat the act again and again. Of all the natural rewards, orgasm is the one that provides the biggest release of dopamine and sensation of pleasure in the reward system of the brain. It is the main tactic in nature’s strategy to keep us fertilising and producing more babies.
But there is a bug in the system, otherwise we’d all fall in love and live happily ever after, and divorce lawyers would not be so busy.