A new study by researchers in France has shown that first-born kids are more likely to be successful but at the cost of being less co-operative and less trusting as compared to their younger siblings.
The study, by researchers at the Institute of Evolutionary Sciences in Montpelier, France, suggests that first-born children are generally smarter and more likely to become leaders compared to their younger brothers and sisters.
However, this makes them more cynical and less likely to trust others or co-operate with them, according to the study, reports the Telegraph.
The findings are based on a study involving 510 students playing a game designed to establish co-operation and trust.
During the game, participants are given 30 monetary units, which they can give some or all to another in the knowledge the amount will be trebled.
The receiver can then return as much money back to the original giver as they want.
The more money the giver gives away the more trusting they are deemed to be and the more the receiver tended to return.
The researchers found that on average eldest siblings gave 25 per cent less money that their siblings suggesting they were 25 per cent less trusting.
The study was published in New Scientist.