Is reading a book a way to get a short-term intelligence top-up? That’s the implication of a study by an Emory University team of neuroscientists, led by Gregory Berns. The Independent reported this as evidence that reading a novel can lead to a “boost” in brain function for “days” afterwards, while the LA Times says it means books “exercise muscles in the brain” so effectively that it can be detected for up to five days afterwards.

The study in question - “Short- and Long-Term Effects of a Novel on Connectivity in the Brain”, published in the journal Brain Connectivity in on 6 December (here’s the link) - isn’t quite as definitive as those headlines make out. It’s one of those instances where the media has fallen for the “[x] ‘rewires’ the brain” myth, one that’s as common (and as mistaken) as the “we only use ten percent of our brainpower” myth, or the “right brain/left brain” myth.

Everything we do makes our thinking organ ‘rewire’ itself, as it works by forming new connections between neurons, creating new neural networks - it’s called neuroplasticity. Those panic stories that appear in the Mail claiming that Facebook/porn/violent movies/etc. are causing long-term damage to the brains of our children are based on the dodgy assumption that those activities cause the brain to reconfigure itself in a harmful way, and for it to then get stuck like that, like pulling a face when the wind changes. Nope, that’s not how it works.

So, to the study. Here’s what it measured: 19 participants (not 21, as reported elsewhere) were scanned by an MRI machine over 19 days. There was a five day “wash-in” period to establish a baseline, nine days over which the participants read the novel, and a five day “wash-out” period to see how long changes were measured.

The book, in this experiment, was Pompeii by Robert Harris. “This novel was chosen because it was based on true events but written as historical fiction and conveyed in a classic narrative arc,” Berns writes. It’s a book that ends with a massive volcano blowing up and everybody dying, so the plot has a pretty predictable build-up and climax that would hopefully show up in the brain scans - and, what do you know, they did:

On the days after the reading, significant increases in connectivity were centered on hubs in the left angular/supramarginal gyri and right posterior temporal gyri. These hubs corresponded to regions previously associated with perspective taking and story comprehension, and the changes exhibited a timecourse that decayed rapidly after the completion of the novel.”

Translation: bits of the brain that do language stuff changed, and started changing back after the book ended. That might seem to justify the idea of books being used to “boost” brain function, but don't be too hasty.

Firstly, 19 participants is a tiny sample size, and secondly, there wasn’t a control group. Instead, “through repeated scans, each participant served as his or her own control to measure changes in resting-state connectivity after the consumption of the novel.” We can be relatively confident, because of this, that the changes in brain connectivity that were observed did happen - but we can’t be sure that it’s the books that caused it. The participants all went through similar experiences over 19 days, of which only a part was reading the same book.

Maybe the changes observed are what happens when you get used to sitting inside a big machine once a day for three weeks. Or, maybe it’s what happens when you take a quiz every day, something that Berns considers in his conclusion:

[Resting-state networks] are known to be altered by recent language comprehension tasks (Hasson et al., 2009) as well as visual categorization tasks (Stevens et al., 2010). Although the chapter readings were performed during the evenings before scans, the quizzes occurred just before the scan. The quizzes, therefore, might be responsible for such immediate changes in resting state, though the tasks differ in their orientation.”

Let’s accept that it is the book that did it - what does it tell us? That a book about a volcano exploding, with a simple plot, changed the structure of a small part of the brains of a small group of people. It’s a leap to then assume that it would lead to a boost in mental ability - either when it comes to the parts of the brain where changes were seen, or across the whole brain.

It also says nothing about what kinds of books cause the change. Is it all novels? Is non-fiction just as good? Is it a narrative that matters, or is experimental fiction just as useful? What about poetry, or fan fiction, or the comments section of YouTube? Or what about an article like the one you’re reading right now?

Scientific discovery tends to be a gradual thing, taking place over many years with many people building up a combined body of knowledge. This study is interesting in that context - not in any kind of way that can be used to attribute magical powers to novels. As much as we may love our favourite books, that's a bit of a stretch.