As human beings, we socially categorise people rather than as individuals. The problem with such categorization is prejudice and discrimination. It causes people to act cruelly towards one another and also causes people to treat others differently than they would someone else of their own category.
We studied the gender based prejudices and stereotypes with an experimental setup known as N400 violation. We discovered that the brain activity changes on presentation of an information violating our worlds knowledge (stereotypes). For example, the sentence “clean rural migrants” elicit a larger N400 response than “dirty rural migrants”, as it violates an existing prejudice. This happened independently of people ideas, conscious beliefs or will.
In the study, we recorded the electrical activity of the brain in 15 Italian university students resident in the Milan metropolitan area, while they read hundreds of sentences off a computer screen. The sentences generally described familiar scenes and common everyday situations. What participants did not know is that half of them violated gender stereotypes (e.g., “The notary is breastfeeding” or “Here is the commissioner with her husband”). We investigated where and how the brain processed gender prejudices and wanted to see if it was possible to measure it without people being aware of it.
We found that the University students of both sexes reacted with violation signals to sentences where women performed typically male jobs and vice versa. These signals were similar to those measured when people find grammatical errors.
These results show that prejudices are so deeply rooted in our mind that their violation is treated like a morphosyntactic or linguistic error.
The world knowledge (including stereotypes) is automatically formed based on media exposure and personal experience. Our brain unconsciously builds a database with which it understands the world and automatically reacts to an event. Indeed, people tend to consciously repress prejudices on the basis of their ideas of equality (either gender or race based). This is our moral brain, representing our beliefs and what is politically right. The moral brain controls our behaviour but it cannot control our brain responses. In this venue, while believing that a woman could be the president consciously, our brain almost considers it an “error”, based on our world knowledge.
One potential study limitation can be the small sample considered, and the lack of analysis of the sex effect. Indeed, it is entirely possible that response violations (prejudices) were greater in male than female participants. We are currently investigating this specific matter.
In this highly connected and digitalized worlds it is important to consider the ton of information that constantly hit us (e.g. TV, social media, smartphones, etc..) and contributes towards shaping our beliefs. Here we showed that gender biased prejudices are elicited automatically “unconsciously” and without our supervision. In other words, it requires an effort to suppress the error signal that our brain produces while reading of an unlikely event (e.g., a female president, or a male nanny).
Research Article: Electrophysiological markers of prejudice related to sexual gender, Neuroscience 2017.