Even before they can talk, babies understand how fortune favours the brawny, research has shown.

Infants aged 10-13 months expect the bigger of two contestants in a conflict to win, a study published in the journal Science found.

Psychologists believe the findings indicate that, like animals, humans are programmed at an early age to respect size.

“Traditional kings and chieftains sit on large, elevated thrones and wear elaborate crowns or robes that make them look bigger than they really are, and subordinates often bow or kneel to show respect to superior humans and gods,” said lead researcher Lotte Thomsen, from the University of Copenhagen in Denmark and Harvard University in the United States.

“Many animals, like birds and cats, will puff themselves up to look physically larger to an adversary, and prostrate themselves to demonstrate submission, like dogs do. Our work suggests that even with limited socialisation, pre-verbal human infants may understand such displays.”

The experiments involved studying the reactions of infants as they watched videos of interacting various-sized cartoon characters - in the films, two squares with eyes and mouths bounced across a stage from opposite directions.

When they met, one gave way to the other with a polite bow. Sometimes a smaller square deferred to a larger one, but on other occasions large gave way to small.

It was already known that when babies see something surprising they tend to spend more time focusing on it.

On average, the babies watched the unexpected outcome for 20 seconds, compared with just 12 seconds when the smaller character moved aside.

A follow-up experiment showed that slightly younger eight-month-old infants fail to notice when big bows to small, suggesting that a grasp of the concept develops between eight and 10 months of age.