What eye pupils tells us about language
The meaning of a word is enough to trigger a reaction in our pupil: when we read or hear a word with a meaning associated with luminosity (“sun,” “shine,” etc.), our pupils contract as they would if they were actually exposed to greater luminosity. And the opposite occurs with a word associated with darkness (“night,” “gloom,” etc.).
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.
DOI PDF: 10.1177/0956797617702699:cp_pupille_et_langage_en_web
The Genes influence the ability to read a person’s mind from their eyes
Not only does the eyes react to trigger words, the eyes are the windows to the soul. In addition, our DNA influences our ability to read a person’s thoughts and emotions from looking at their eyes, suggests a new study published in the journal Molecular Psychiatry.
Twenty years ago, a team of scientists at the University of Cambridge developed a test of ‘cognitive empathy’ called the ‘Reading the Mind in the Eyes’ Test (or the Eyes Test, for short). This revealed that people can rapidly interpret what another person is thinking or feeling from looking at their eyes alone. It also showed that some of us are better at this than others, and that women on average score better on this test than men.
Now, the same team, working with the genetics company 23andMe along with scientists from France, Australia and the Netherlands, report results from a new study of performance on this test in 89,000 people across the world. The majority of these were 23andMe customers who consented to participate in research. The results confirmed that women on average do indeed score better on this test.
More importantly, the team confirmed that our genes influence performance on the Eyes Test, and went further to identify genetic variants on chromosome 3 in women that are associated with their ability to “read the mind in the eyes.”
The study was led by Varun Warrier, a Cambridge PhD student, and Professors Simon Baron-Cohen, Director of the Autism Research Centre at the University of Cambridge, and Thomas Bourgeron, of the University Paris Diderot and the Institut Pasteur.
Interestingly, performance on the Eyes Test in males was not associated with genes in this particular region of chromosome 3. The team also found the same pattern of results in an independent cohort of almost 1,500 people who were part of the Brisbane Longitudinal Twin Study, suggesting the genetic association in females is a reliable finding.
The closest genes in this tiny stretch of chromosome 3 include LRRN1 (Leucine Rich Neuronal 1) which is highly active in a part of the human brain called the striatum, and which has been shown using brain scanning to play a role in cognitive empathy. Consistent with this, genetic variants that contribute to higher scores on the Eyes Test also increase the volume of the striatum in humans, a finding that needs to be investigated further.
Previous studies have found that people with autism and anorexia tend to score lower on the Eyes Test. The team found that genetic variants that contribute to higher scores on the Eyes Test also increase the risk for anorexia, but not autism. They speculate that this may be because autism involves both social and non-social traits, and this test only measures a social trait.
Varun Warrier says: “This is the largest ever study of this test of cognitive empathy in the world. This is also the first study to attempt to correlate performance on this test with variation in the human genome. This is an important step forward for the field of social neuroscience and adds one more piece to the puzzle of what may cause variation in cognitive empathy.”
Professor Bourgeron adds: “This new study demonstrates that empathy is partly genetic, but we should not lose sight of other important social factors such as early upbringing and postnatal experience.”
Professor Baron-Cohen says: “We are excited by this new discovery, and are now testing if the results replicate, and exploring precisely what these genetic variants do in the brain, to give rise to individual differences in cognitive empathy. This new study takes us one step closer in understanding such variation in the population.”
DOI PDF: 10.1038/MP.2017.122:Warrier