They found that rejected chimps raised lovingly by human carers are cleverer than the average human baby up to the age of nine months.

And they said the findings were a “stark warning” that children needed love as well as physical care or they risked growing up “maladjusted, unhappy and under-achieving”.

The study is the first to compare the effects of the way chimp and human babies are raised.

Professor Kim Bard, of the Centre for the Study of Emotion at the University of Portsmouth, studied the care records of 46 baby chimps at risk of death through neglect by their mothers.

A group of 17 given “responsive care” had human carers looking after them 20 hours a week. They tended to their physical and emotional needs, grooming, feeding and interacting with them. Professor Bard then looked at a second group of 29 given standard care catering only for physical needs.