A new study has found that men who watch pornography may be shrinking their brains and dulling their responses to sexual stimulation. Dr Simone Kühn, the study’s lead author from the Max Planck Institute in Berlin, said it was the first evidence for a link between porn consumption and reductions in brain size and brain activity in response to sexual stimuli. However, an alternative explanation is that people who spend more time looking at pornography are born with a certain type of brain.

People who already have a smaller ‘striatum’ a brain region that has been associated with motivated behaviour may be more likely to use pornography.

‘It’s not clear, for example, whether watching porn leads to brain changes or whether people born with certain brain types watch more porn’ she said.

For the study, Dr Kuhn and her colleague Jurgen Gallinat from Charite University, also in Berlin, recruited 64 healthy men between the ages of 21 and 45 years and asked them questions about their porn-watching habits. They found noticeable differences in the men who abstained compared with those who regularly accessed sexual videos or images. They found that the volume of the so-called striatum, was smaller the more pornography consumption the participants reported.

‘Moreover we found that another brain region, that is also part of the striatum that is active when people see sexual stimuli, shows less activation the more pornography participants consumed.’

Dr Kuhn said other behaviours, such as driving a taxi are linked to changes in brain size and functioning. ‘Basically everything that people do very frequently can shape their brain structure and function’ she added.

However other researchers claimed that pornography in moderation was probably not damaging.