Professor Paul Bloom of Yale University believes he can detect morality in children aged just one year old.

Infants are shown a puppet morality play and asked to pick a puppet for themselves, either a "good" puppet or a "bad" one.

Horizon: Are you Good or Evil? was broadcast on BBC Two on Wednesday 7 September at 9pm on BBC Two and is available via iPlayer until 21 September at the above link (UK only).