Oh no, she’s at it again. For some years now the neuroscientist Baroness Susan Greenfield has been claiming that over-use of the internet will rewire our minds, and especially will damage those of small children.

“We know how small babies need constant reassurance that they exist,” she warns. “My fear is that these technologies are infantilising the brain into the state of small children who are attracted by buzzing noises and bright lights, who have a small attention span and who live for the moment.”

In April, in a piece for the Daily Mail, she declared that “human identity could be facing an unprecedented crisis” because of the threat of new technologies and earlier this summer she claimed during a House of Lords debate that exposure to computer games, instant messaging, chat rooms and social networking sites could leave a generation with denuded attention spans.

Now she’s come up with a new killer theory. Writing last month in New Scientist, she suggested that there is a link between internet usage and autism – much to the fury of scientists like Dr Dorothy Bishop, an Oxford professor of neuropsychology, who described her outburst as “illogical garbage”, unsupported by any evidence.

This is hardly a surprise given that none of her previous pronouncements have been backed by credible empirical findings. This has been pointed out more than once, but for a respected scientist Baroness Greenfield seems inexplicably impervious to this criticism. For example, she reacted with astonishing insouciance when Ben Goldacre, in his Bad Science column in the Guardian, wondered why Greenfield had offered no evidence for her assertions. “Baroness Greenfield’s response to my concerns, and my suggestion that she should write up her concerns about computers damaging children’s brains formally,” he later wrote, “has been to say that I am like the people who denied that smoking caused cancer.”

Greenfield, who has so far demonstrated little appetite for researching this subject, is unlikely to be impressed by the work of my own colleague at the University of Westminster, Professor David Gauntlett. He led a BBC-sponsored study of how young children respond to the digital world, based on the interactions between primary school children and a closed virtual environment, Adventure Rock. “Our study found that children could use digital tools imaginatively and well, and I have no evidence that children’s brains are being rewired,” Gauntlett told me. “But to be fair, I don’t think Susan Greenfield has got any evidence of that either.” His criticism is not of the internet itself, but of the designers of these games “who often failed to provide children with the kinds of tools which would really encourage and enable creativity.”

And now a new study by three leading economists confirms not only that digital networking does no harm – but that it can have real social benefits. Presenting their work to a gathering of Nobel-prize winners, Stefan Bauernschuster, Oliver Falck and Ludger Woessmann of the Ifo Institute in Munich found that use of the internet increased children’s out-of-school activities, as well as extending friendships.

It seems unlikely, though, that these findings will make much difference to Greenfield’s beliefs. Rather than seeking any counter-evidence to strengthen her claims, she’s now writing a novel, inspired by her obsession with the looming dangers of new technologies. She claims her novel will not be a “bodice-ripper”, but I wouldn’t bet on it. Her hero is a dashing 22nd-century neuroscientist fighting the cyber wars, and with three women in his life.

Three women? Even one would be dangerous, according to the psychologist Susan Quilliam. Writing in the Journal of Family Planning and Reproductive Health Care, she blames romantic novels for “unprotected sex, unwanted pregnancies, unrealistic sexual expectations and relationship breakdowns”.

Her comments follow the claims of Christian psychologist Dr Juli Slattery that romance novels can “dangerously unbalance” their readers. Writing on KSL.com, a news website owned by the Church of Jesus Christ of Latter-Day Saints, she said she was seeing “more and more women who are clinically addicted to romantic books”, and that “for many women, these novels really do promote dissatisfaction with their real relationships.”

This theory is not only eccentric – it’s downright insulting. Where’s the evidence for the absurd assumption that women can’t tell the difference between fact and fiction? No doubt the Qulliams and Slatterys might argue, rather as Greenfield did when her views on cyberspace were challenged, that deniers of such an obvious cause and effect are as bad as those who wouldn’t admit that smoking causes cancer. And this comparison does leave Greenfield floundering in something of a paradox. By writing a novel intended to warn against one terrible danger to our brains, she may well be contributing to an even more potent threat to civilisation.