Researchers have used a Reddit thread about rape to analyse the psychology of sexual violence.

The Reddit discussion, dubbed "ask a rapist", allowed self-identifying rapists to narrate their experiences anonymously.

It caused a storm online when it appeared and was later removed, but researchers from Georgia State University used the comments to look at how rapists justified their actions.

The study, published in the journal Psychology of Violence, examined how rapists abdicated responsibility for their actions.

The Reddit thread began in July 2012 when a commenter posted: "Reddit's had a few threads about sexual assault victims, but are there any redditors from the other side of the story? What were your motivations? Do you regret it?"

The responses made for difficult reading.

The thread caused an outcry, with many claiming it allowed rapists to achieve a level of catharsis through crafting their own narrative of the events, often one in which they were not to blame and their actions are inevitable.

Some tried to justify what they had done in terms of a biological need, with one commenter writing that "[a]n erect dick has no conscience", and many of the posts pushed the blame onto the victim.

Because the posts were anonymous, the researchers accepted that some of the stories might be false, but they also recognised that if they were true they might offer some unusually frank insights into the psychology of rape.

The study narrowed the original 12,000 posts to just 68 supposedly fist-hand accounts, taking those from the first two days of postings on the basis that those ones would be less likely to have been influenced by the media attention the thread was getting.