Warning: this story contains a paragraph of disgusting text.

How can reading a good book or watching a film be almost as emotional an experience as events in your own life? The answer may be that you use the same brain region to make sense of them all.

Previous studies indicated that the same brain regions – the anterior insula and adjacent frontal operculum, known collectively as the IFO – are activated both when we observe someone experiencing an emotion such as disgust, delight or pain, and when we experience it ourselves.

It is thought that this allows us to empathise with others and understand their intentions. But is the IFO also active when we imagine an emotion, such as when we read about it in a book?


Yuk yuk yuk

To answer this question, Mbemba Jabbi and colleagues at the University of Groningen in the Netherlands, focused just on disgust – an easy emotion to evoke. “You can’t just tell someone to get into a scanner and be ‘happy’ for 30 seconds,” says co-researcher Christian Keysers. “But it’s relatively easy to make someone disgusted.”

They placed quinine – which has a bitter, “disgusting” taste – onto the tongues of 12 volunteers while they lay in an MRI scanner. The volunteers also watched a video of someone acting disgusted and read a story describing a disgusting situation:

You turn around because someone is leaning on your shoulder, suddenly looking into the open mouth of a drunken beggar you see his rotten teeth, surrounded by pustulant sores, while he suddenly releases the reeking content of his stomach all over you You feel your stomach turn over as you suddenly feel the acidic taste of a clump of his vomit on your lips.

The researchers found that the IFO was activated in all three tasks. They say this similarity between first-hand experience and imagination could help to explain why books can be so vivid and compelling.

Understanding others

“There is a partial overlap – if you taste something disgusting, see something disgusting or imagine a disgusting scenario there’s a common pathway,” says Keysers. “This is why books and movies work – because they stimulate the area of the brain which is involved in what it really feels like to be disgusted.”

The team suspects that reading about delight or pain also activates similar converging networks in the brain.

The next step will be to study IFO activation in autism. It is generally assumed that autistic people can’t identify the emotions of others, but clinical studies alternatively suggest that perhaps they feel others’ emotions too well, to the point that they are overwhelmed. “These experiments can help tease these options apart,” says Keyser.

Journal reference: PLoS ONE, DOI: 10.1371/journal.pone.0002939

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