Why do you need a brain to fall in love?

THAT'S THE WHY:Love hearts: they might seem romantic or tacky, depending on your current frame of mind, but they are a common symbol of that hard-to-describe feeling of overwhelming fondness for another human being.

If you really think about it though, when we are in love we should be adorning our Valentine’s Day cards not with hearts, but with brains instead. Because inside your skull is where the real frenzy starts as you fall madly in love and stay there.

It might not sound terribly tender, but there’s a scientific model for the process of falling in love, and it’s carved up into three stages.

First up is lust, driven by the hormones testosterone and oestrogen. The levels of these rampaging hormones ultimately are orchestrated by the hypothalamus, which lies deep within the brain.

After that comes the attraction phase. This appears to involve a cocktail of brain chemicals, including dopamine, which lights up our reward pathways.

Meanwhile, the effects of another brain chemical – serotonin – seem to be blunted in the smitten brain, which may help to keep it slightly fixated on the new amour.

Of course if the human species spent its whole time infatuated, in that acute attraction phase, we’d never get any work done, so the next phase is a longer-term attachment, where a central player is the brain chemical oxytocin. Sometimes known as the “cuddle hormone” because close physical contact can prompt its release, it is secreted by the pituitary gland, which – you guessed it – resides in the brain.

So start practising those brain doodles for the Valentine’s cards for next year.