A fascinating book by Rita Carter, Multiplicity: The new Science of Personality (London: Little, Brown, 2008), argues that the impression you have of being a single, unified personality is an evolutionary illusion. In fact, it makes just as much sense – more, perhaps – to think of yourself as yourselves.

Think about it. If you’re like most of us you probably dress, behave, speak and even think differently when you’re in work mode than when you’re in parent, or study, or clubbing mode.  You’d be odd if you didn’t! Maybe you like to get out of your work clothes when you get home, perhaps fix yourself a drink and crash out for a bit – that’s if you’re lucky enough not to have to fix dinner for everyone first.  Maybe you find in certain circumstances – when you’re behind the wheel of a car, or dealing with a particular person, or you’ve had a few drinks, or someone gets you angry – you seem to turn into a different person. If anyone ever says about you, “That’s not like you,” then you’ll know what I mean. Except it is like you: just not the you that they usually meet.

This can be particularly obvious with sportspeople – the “white line fever” effect. There’s many a hard man on the football field who, off it, is quiet, reserved and polite (Bryan Robson, Mark Hughes).

You may wish to think of there being several different personalities all sharing our body as a metaphor, a way of understanding our behaviour better, rather than a ‘fact’ (whatever that might mean in this context).  If it does help you make sense of how you are, use it!