* detect lies * make your smile more attractive, more trustworthy and less dominant This psychology study found that a long-onset smile (0.5s onset) is seen as more authentic and flirtatious than a short-onset smile (0.1s). On top of this, the researchers found long-onset smiles were perceived as more attractive, more trustworthy and less dominant. * persuade others your opinion represents the whole group If you want to convince others that your opinion is representative of the majority, then just repeat yourself. * have a refreshing holiday * avoid getting scammed If I had to explain only one thing to someone who knew nothing about psychology, it would be 'crowd psychology'. * Using email to persuade * Find out if you're satisfied with your relationship * Reduce your cholesterol levels According to this early data, affectionate writing can reduce cholesterol levels. * make friends with self-disclosure