Hormones have a huge impact on behaviour, in women this is particularly apparent as changes during their monthly cycle, and around puberty, childbirth and menopause. The reason that some women experience depression after giving birth is complex, and we don’t fully understand it. It seems that hormones have a role to play.

Hormones such as testosterone affect emotions and behaviour in men too. Testosterone affects the brain, including areas associated with emotion. Researchers are still exploring a potentially complex link between testosterone levels and moral behaviour.