All in the eyes: What the pupils tells us about language

These results, published on 14 June 2017 in Psychological Science by researchers from the Laboratoire de psychologie cognitive (CNRS/AMU), the Laboratoire parole et langage (CNRS/AMU) and the University of Groningen (Netherlands), open up a new avenue for better understanding how our brain processes language.

The researchers demonstrate here that the size of the pupils does not depend simply on the luminosity of the objects observed, but also on the luminance of the words evoked in writing or in speech. They suggest that our brain automatically creates mental images of the read or heard words, such as a bright ball in the sky for the word "sun," for example. It is thought that this mental image is the reason why the pupils become smaller, as if we really did have the sun in our eyes.

This new study raises important questions. Are these mental images necessary to understand the meaning of words? Or, on the contrary, are they merely an indirect consequence of language processing in our brain, as though our nervous system were preparing, as a reflex, for the situation evoked by the heard or read word? In order to respond to these questions, the researchers wish to pursue their experiment by varying the language parameters, by testing their hypothesis in other languages, for example.