Why do little girls like pink ?

Probably because of social pressure. In Britain and the USA, older girls like pink more than boys do, but they could already have been influenced by expectations. So studies have tested one- to two-year-old's by using the ‘preferential looking task’, which measures what the children like to look at the most. The studies found that preference for toys differ by sex, with boys looking longer at cars and girls at dolls, but preference for color do not. So perhaps it’s not surprising that back in 1918 the trade publication Earnshaw’s Infants’ Department wrote that babies’ clothes should be pink for a boy and blue for a girl.

Why do people cheat?

Because they want to win the easy way. As competitive animals, we human beings constantly seek out opportunities to gain money, food and sex, or simply to look good. Doing all this the hard way requires expenditure of time,efforts and energy, so cheating can obviously be very tempting.

Evolutionary game theory has helped to explain how altruism can exist alongside cheating. Generally, cheats do well when they are rare, but less well when they are many and have fewer non-cheaters they can exploit. So groups tend towards an equilibrium, with few enough cheats that it’s not worth the cost of stopping them. Sadly, this basic biological principle means we are unlikely ever to be completely free of cheats.