It turns out, there’s a reason why people love to talk about themselves so much on Twitter, Facebook and other social media – And, no, cynics, it’s not just because that’s what everyone thinks those services are there for. A new study from the Harvard Social Cognitive and Affective Neuroscience Lab has discovered that it feels really good when we share information about ourselves, in the same way that it feels really good when we have sex. Suddenly, that Pinterest site you were thinking about setting up about yourself feels a little creepy, doesn’t it…?

Studies have shown that 80 percent of the average user’s social media posts – and 30-40 percent of the average person’s speech output each day, for that matter – consist of self-disclosure, leading scientists to consider just why we’re all so convinced with talking about ourselves. Harvard SCAN Lab‘s Diana Tamir and co-author Jason Mitchell took on the question, hooking subjects up to an MRI machine to monitor brain activity as they answered questions about their own and others’ attitudes on various subjects (including, amusingly, Barack Obama’s enjoyment of winter sports such as skiing) in case there was a discernible difference. The result [pdf] was the discovery that talking about yourself engages two areas of the brain associated with reward – the nucleus accumbens (NAcc) and the ventral tegmental area (VTA) – in ways that talking about other subjects just… doesn’t.

For those unfamiliar with brain regions, the nucleus accumbens is part of the brain most commonly linked to concepts of reward, pleasure and addiction, considered important in the processing of such pleasurable activities as sex or good food. The ventral tegmental, meanwhile, is similarly linked to reward processing, as well as pleasurable feelings we get from being in love. So, basically, talking about yourself is just like having sex while eating chocolate. Or something.

Tamir and Mitchell also considered whether or not having an audience was responsible for the reward felt when sharing information about yourself, with Tamir telling the LA Times that “We didn’t know if self-disclosure was rewarding because you get to think about yourself and thinking about yourself is rewarding, or if it is important to have an audience.” The result, perhaps unsurprisingly, is that mental reward activity comes with the knowledge that someone they know is receiving the information being given, compared with sending information out into a void. Tamir believes that this explains the success of social media: “I think it helps explain why Twitter exists and why Facebook is so popular, because people enjoy sharing information about each other.”

All that remains now is for someone to monitor the brain activity of someone live-tweeting themselves eating chocolate during sex… but I’m sure that’ll happen before too long.