The French research team that made the latest contribution to this effort presents its findings in the current issue of the journal NeuroImage. Referring to a part of the brain known as the “ToM network,” the researchers write, “We demonstrate that the ToM network becomes active while a participant is understanding verbal irony.”
This isn’t just one of those “shot in the dark” MRI studies, where you see what brain regions happen to light up when people engage in a particular mental activity. The ToM network has been the focus of previous work on irony apprehension, and enough is known about it to give us some ideas about the particular role it could play in that apprehension.
Here’s how the experiment worked. The researchers prepared short written stories, and each story came in two versions. Both versions contained a sentence that could be read either literally or ironically, with the correct reading depending on how the context had been set earlier in the story. In one story, for example, one opera singer says to another, “Tonight we gave a superb performance,” and whether the sentence is ironic or literal depends on whether the performance had been described earlier in the story as a failure or as a success. The researchers had correctly predicted that the ToM network would show more activity when the sentence, read in context, was ironic than when it was literal.
ToM stands for “theory of mind,” which in turn refers to the fact that we naturally attribute beliefs and intentions and emotions to people we interact with. That is, we develop a “theory”–though not necessarily a theory we’re consciously aware of–about what’s going on in their minds. (An inability to do this is thought to play a role in autism.) And this “theory” in turn shapes our interpretation of things people say. The “ToM network” is a brain region–or, really, a network of different brain regions–that seems to play an important role in the construction of these theories.
It makes sense that parts of the brain involved in theorizing about other people’s minds would be involved in grasping irony. After all, detecting irony means departing sharply from the literal meaning of a sentence, something it’s hard to do without having a “theory” about the intent behind the sentence.
Consider Twitter: I sometimes wonder, reading sarcastic tweets from someone I know, how they’re interpreted by people less familiar with the tweeter’s mind than I am. And it seems to me that people who don’t know the tweeter but correctly sense the irony must, in the process, develop a kind theory about the tweeter’s mindset. …