The brain’s ability to change its own structure, as Carr sees it, is nothing less than ‘a loophole for free thought and free will’. But, he hastens to add, ‘bad habits can be ingrained in our neurons as easily as good ones.’ Indeed, neuroplasticity has been invoked to explain depression, tinnitus, pornography addiction and masochistic self-mutilation (this last is supposedly a result of pain pathways getting rewired to the brain’s pleasure centres). Once new neural circuits become established in our brains, they demand to be fed, and they can hijack brain areas devoted to valuable mental skills. Thus, Carr writes: ‘The possibility of intellectual decay is inherent in the malleability of our brains.’ And the internet ‘delivers precisely the kind of sensory and cognitive stimuli – repetitive, intensive, interactive, addictive – that have been shown to result in strong and rapid alterations in brain circuits and functions’. He quotes the brain scientist Michael Merzenich, a pioneer of neuroplasticity and the man behind the monkey experiments in the 1960s, to the effect that the brain can be ‘massively remodelled’ by exposure to the internet and online tools like Google. ‘THEIR HEAVY USE HAS NEUROLOGICAL CONSEQUENCES,’ Merzenich warns in caps – in a blog post, no less.