Facebook “friending” may fry your brain.

The social-networking site lets users rack up as many as 5,000 friends, but the mind cannot handle more than 150 relationships at one time, a new study has found.

Proponents of Twitter and Facebook say the technology helps people build larger, deeper social networks, but the truth, says Oxford University anthropologist Robin Dunbar, is that Web 2.0 can’t win over Brain 1.0.

In the 1990s, through his studies of primates, Dunbar settled on the figure of 150, which he said is the largest social network the brain’s neocortex, in even the most social of social butterflies, can handle.

Known as “Dunbar’s Number,” the figure has been the subject of much debate over the years, with many social scientists speculating that people may actually be able to maintain close to twice that many relationships.

Dunbar recently set out to determine whether Facebook and Twitter enable the mind to stretch and handle a great number of social connections.

The answer appears to be no, he told The Times of London.

“The interesting thing is that you can have 1,500 friends, but when you actually look at traffic on sites, you see people maintain the same inner circle of around 150 people that we observe in the real world,” Dunbar said.

He arrived at his number through studying social groupings in a variety of societies, from Neolithic villages to modern office environments.

The neocortex of the brain developed roughly 250,000 years ago during the Pleistocene era.

The 150 limit corresponds roughly to the size of a Neolithic farming village, as well as the size of a unit of the Roman army. In groups greater than 150, social cohesion begins to disintegrate, Dunbar said.

“People obviously like the kudos of having hundreds of friends, but the reality is that [their social network] is unlikely to be bigger than anyone else’s,” he said.

Dunbar is still conducting research into the social-networking sites, and expects to publish his final results later this year.

jeremy.olshan@nypost.com

