(PhysOrg.com) -- The currently prevailing theory on human development is that human beings start their lives with a "moral blank state," but new research contradicts this view. The researchers have found babies as young as six months old already make moral judgments, and they think we may be born with a moral code hard-wired into our brains.

The research was carried out by a team led by Paul Bloom, professor of psychology at the Infant Cognition Center at Yale University in Connecticut in the US, and used the ability to differentiate between unhelpful and helpful behavior as their indicator of moral judgement. The results contradict the theories of Sigmund Freud and others, who thought human beings start out as “amoral animals”, or a moral blank state. Bloom said there is mounting scientific evidence that this may not be true and that “some sense of good and evil seems to be bred in the bone.”

In one experiment babies between six and ten months old were repeatedly shown a puppet show featuring wooden shapes with eyes. A red ball attempts to climb a hill and is aided at times by a yellow triangle that helps it up the hill by getting behind it and pushing. At other times the red ball is forced back down the hill by a blue square. After watching the puppet show at least six times the babies were asked to choose a character. An overwhelming majority (over 80%) chose the helpful figure. Prof. Bloom said it was not a subtle statistical trend as “just about all the babies reached for the good guy.”

In another experiment the babies were shown a toy dog puppet attempting to open a box, with a friendly teddy bear helping the dog, and an unfriendly teddy thwarting his efforts by sitting on him. After watching at least half a dozen times the babies were given the opportunity to choose one of the teddy bears. The majority chose the helpful teddy.

A third experiment used a puppet cat playing with a ball with a helpful rabbit puppet on one side and an unhelpful rabbit on the other. The helpful rabbit returned the ball if the cat lost it, while the unhelpful rabbit stole the ball and ran off with it. In this test five-month-old babies were allowed to choose one of the rabbits, and most chose the helpful one. When the test was repeated with 21-month-old babies they were asked to take a treat from one of the rabbits. Most took the treat from the unhelpful rabbit, and one even gave the rabbit a smack on the head as well.

Lead author of the study, Kiley Hamlin, said people worry a lot about teaching children the difference between good guys and bad guys but “this might be something that infants come to the world with.” Other psychologists have cautioned that adult assumptions can affect how babies’ reactions are interpreted, and that babies begin to learn from the moment they are born.

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