Selecting a mate is the most crucial decision of our lives. We spend a huge amount of time and energy trying to find that special someone. Our appetite for a relationship fuels a billion-dollar industry of match-making services, lonely hearts ads and online dating. Yet we’re often not satisfied. A survey in 2005 of more than 900 people who had been using online dating services found that three-quarters had not found what they were looking for. We seem as much in the dark as ever about who is a suitable match for us.

As a scientist studying human behaviour, I am not too surprised by the mysterious nature of how we go about choosing a partner. Mate selection is a highly complex process. We are consciously aware of only part of it; the rest is either inherently unpredictable or operates outside our awareness, which leads us to the perception that love is about ineffable chemistry.

Let’s start with the conscious part. There are some things we all find attractive. Men tend to desire women with features that suggest youth and fertility, including a low waist-to-hip ratio, full lips and soft facial features. Recent studies confirm that women have strong preferences for a virile male beauty – taut bodies, broad shoulders, clear skin and defined, masculine facial features, all of which may indicate sexual potency and good genes. We also know that women are attracted to men who look as if they have wealth, or the ability to acquire it, and that both men and women strongly value intelligence in a mate. Preferences for these qualities – beauty, brains and resources – are universal. The George Clooneys …