For instance, said Mahon, most living things have curved forms, and so many scientists thought the brain prefers to process images of living things in an area that is optimised for curved forms.

To see if the appearance of objects is indeed key to how the brain conducts its processing, Mahon and his team, led by Alfonso Caramazza, director of the Cognitive Neuropsychology Laboratory at Harvard University, asked people who have been blind since birth to think about certain living and non-living objects.

These people had no visual experience at all, so their brains necessarily determined where to do the processing using some criteria other than an object's appearance.

'When we looked at the MRI scans, it was pretty clear that blind people and sighted people were dividing up living and non-living processing in the same way,' said Mahon.

These findings were published in Neuron.