你诚实吗？你撒过慌、骗过人吗？在生活、工作中，诚实一定是上策吗？

Let's be honest – I'm sure we've all done something a little dishonest in our lives – maybe copying someone's work, borrowing some money from a friend and not paying them back or being given too much change in a shop and keeping quiet about it. Or maybe I'm wrong, maybe you're a good, upstanding citizen who believes that honesty is the best policy.

This proverb, 'honesty is the best policy', was written back in the 1700s by American statesman, Benjamin Franklin. We may agree that owning up to our mistakes and behaving in a genuine and decent way, is the right way to lead our lives but is there something in our human nature that makes us unscrupulous? For example, in some shops and car parks you can find an honesty box – a box where you pay for something by putting money in it – but it relies on you putting the right amount of cash in. This relies on people being honest and not trying to cheat but it does provide a temptation to get away with not paying the full amount.

Philip Graves, a psychologist, and author of the book Consumerology, suggests that this temptation is part of our evolution. He says: "We have evolved with the capacity to be dishonest. It's part of our evolutionary psychological make up – because if we can gain an advantage over the people around us, we have a greater chance of surviving."

So why do we place such importance on being honest if we benefit from being dishonest? It's because it is selfish behaviour – which other members of our social group won't like. If everybody acted selfishly and dishonestly all the time, the world would be a very unpleasant place. As Philip Graves says: "There is a balance to strike between the extent to which we can feather our own nest, so to speak, and the risk of being ostracised by the group." So, for societies to work together we need to trust each other and therefore we need to be honest.

Being trustworthy with money is of course crucial for an economy to survive and there are laws to protect us from dishonest practices like corruption and fraud. But being honest with words is another matter; saying what we think to someone can get us into hot water. However a new anonymous messaging app has been designed that lets anyone with a link to your profile to send you a message without knowing who it's from. The app now has 300 million users which perhaps indicates how honest we really like to be – but in all honesty, do you want to know what people think about you? Is honesty always the best policy?!