Infants who have not yet learned language can still tell friend from foe. Babies aged around six months prefer people who co-operate, rather than people who hurt. This ability could be the foundation for moral thought and action later in life, say researchers.

Previous studies had showed that babies prefer physically attractive people, but there has been no data on whether babies judge people based on how they behave. Simple experiments were conducted to gauge whether six and 10-month-old infants preferred social individuals (helpers) or anti-social individuals (hinderers). The infant was made to watch a 'climber' (a wood puppet with large eyes glued on to it) repeatedly try to climb a hill. On the third try, the climber was either given help or was pushed back down by a puppet. The babies were then given the chance to reach out and grasp either the helper or hinderer puppet. Very high rates of babies chose the helping character. The authors argue it is something innate, rather than babies learning the behaviour.