They explain that all these characteristics contribute to 'cuteness' and trigger our caregiving behaviours, which is vital because infants need our constant attention to survive and thrive. The study is published in the journal Trends in Cognitive Sciences.

Morten Kringelbach, who together with Eloise Stark, Catherine Alexander, Professor Marc Bornstein and Professor Alan Stein, led the work in the Department of Psychiatry at the University of Oxford, said: 'Infants attract us through all our senses, which helps make cuteness one of the most basic and powerful forces shaping our behaviour.'

Reviewing the emerging literature on how cute infants and animals affect the brain, the Oxford University team found that cuteness supports key parental capacities by igniting fast privileged neural activity followed by slower processing in large brain networks also involved in play, empathy, and perhaps even higher-order moral emotions.

The data shows that definitions of cuteness should not be limited just to visual features but include positive infant sounds and smells. From an evolutionary standpoint, cuteness is a very potent protective mechanism that ensures survival for otherwise completely dependent infants.

Professor Kringelbach said: 'This is the first evidence of its kind to show that cuteness helps infants to survive by eliciting caregiving, which cannot be reduced to simple, instinctual behaviours. Instead, caregiving involves a complex choreography of slow, careful, deliberate, and long-lasting prosocial behaviours, which ignite fundamental brain pleasure systems that are also engaged when eating food or listening to music, and always involve pleasant experiences.'

The study shows that cuteness affects both men and women, even those without children.

'This might be a fundamental response present in everyone, regardless of parental status or gender, and we are currently conducting the first long-term study of what happens to brain responses when we become parents.' said Professor Kringelbach.