Babies are smarter than previously thought and can understand complex social situations at 13 months old, psychologists have claimed.
In an experiment with puppets the children responded to scenarios in a way that suggested they were more engaged than had been expected.
They were observed to have “strong feelings about how people should deal with a character who hits others”, the researchers said.
The psychologists asked parents of 48 infants aged around one to bring them into the lab for the experiment.
The babies sat in front of a stage where two puppets, A and B, appeared, initially interacting in a friendly manner.
The psychologists, from the University of Missouri in the US, then used the puppets to play out various scenarios.
A third puppet, C, was introduced and was deliberately knocked down by B as A looked on. In the next scenario, B knocked down C, but A was absent.
A third scenario involved C being accidentally knocked down as A looked on.
The researchers monitored how long the babies looked at the stage to gauge their interest and engagement.
They found babies looked longer at things that were not expected.
The study is published in the journal Psychological Science.