Fully grown humans are less logical than babies and chimps, according to new research.
Scientists say that the constant pressure for grown-ups to outdo their peers makes them perform worse.
Removing this barrier allows the apes - and infant humans - to process things in a more logical way.
The findings, published in the journal Proceedings of the Royal Society B, investigated how mental processes are affected by two facets of society: competition and co-operation.
Both play critical roles in enhancing human knowledge and scientists have found that people often find it very difficult to not compete with others.
Scientists from the US and Germany say that coming out on top can sometimes be to our detriment.
The researchers tested 96 children aged between five and ten from three Kenyan schools and asked them to complete the same task as 15 chimpanzees.
They were required to sit opposite a peer and had two trays with treats were presented to them.
Both trays came with their own set of conditions.
One allowed the subject to obtain two snacks and their counterpart would be given one while the other tray gave the chooser three and their fellow participant six.
Chimps and younger children (younger than six) acted rationally and picked the second option which gave them more treats - three instead of two.
However, older children were also tested which ranged in age up to ten, and this study found they were more concerned with the amount their peer was getting when picking the more fruitful option.
Instead of taking three and giving them six, they decided to 'win' the fictional battle of who gets more treats by choosing the other tray.
'Young children and chimpanzees behaved in a rational manner: they were highly consistent in their choice of the option that maximised absolute pay-off,' the authors of the study wrote.
'Older children, however, acted in an irrational manner [from a pay-off perspective]: they paid a cost to be at a relative advantage compared with a peer and thus maximised relative rather than the absolute pay-off.'
This article has been adapted from its original source.
© Associated Newspapers Ltd.