Swear by it: Human evolution and the science of ‘bad’ language | Interview with Dr Emma Byrne

In anticipation of the Rosalind Franklin Lecture on 6 March, we spoke with  2025 Rosalind Franklin Lecture Medallist, science writer and broadcaster Dr Emma Byrne. In celebration of International Women’s Day, Emma will present the Rosalind Franklin Lecture on the subject of ‘The Amazing Science of Bad Language’ on 6 February 2025. 

Hi Emma! In your Rosalind Franklin Lecture, you’ll be exploring the evolutionary origins of bad language. Why might profanity be useful to our survival?

One of the most astonishing bits of research I encountered when writing the book came from a chimpanzee adoption study. An extended family of chimpanzees spontaneously developed swearing. It showed that three things are sufficient to allow swearing to develop: a taboo, a word relating to that taboo, and an emotional state that you want to communicate. While we can never know for sure, my intuition is that swearing is a huge evolutionary advantage. It allows us to work together without physical violence – even in high-stress situations where conflict may be inevitable!

Is there a difference in how men and women are perceived when they swear?

The difference is largely one of perception. In British English, women tend to swear as much as men (albeit using slightly milder forms), but research shows that women are judged as more unpleasant, more unreliable, and more unlikeable than men when swearing. There’s a long history of who gets to swear, and much of it is about maintaining social hierarchies. Civility usually favours the status quo.

How do taboos around language change over time – especially for women?

It’s hard to predict what will be taboo, especially with the political upheavals we’re seeing in the USA. In the 1990s, as I came of age, many slurs became taboo, while body parts and bodily functions started to show up more in culture and conversation. While slurs haven’t exactly become swearwords, I’m nauseated to see these slurs being used – proudly and joyfully – by people who want women and minorities to shut the fuck up.

What happens in the brain when we swear, and when we’re in pain?

Swearing is surprisingly widely distributed in the brain. When someone suffers damage to the left side of the brain they are likely to lose their ability to speak as a consequence. However, these same patients can, in highly emotional circumstances, produce really fluent swearing! We still aren’t entirely sure how swearing helps with pain, but we do know that it works. There is a limit – both in terms of how much longer people can withstand pain, and how much pain it works for. Studies show that, in times of extreme distress, even swearing deserts us.

Do all cultures swear in the same way, or are there fundamental differences in what is considered offensive?

Cultures vary widely in what is considered offensive. For example, in France, religious swearing (using God’s name in vain and variations thereof) is rarely used, whereas in French-speaking parts of Canada, religious swearing is common and highly offensive. Other cultures use names of animals and illnesses as really strong language. Local taboos shape local swearing.

Are you a humanist? What resonates with you about the humanist approach to life?

I’m definitely a humanist. The more I study the function and structure of human minds, the more I realise that we are shaped first and foremost by one another. We’re social animals, interdependent by nature. All we have is one another. ‘Think for yourself, act for everyone’ seems to me to be the only way we have ever progressed as a species.

Are there any Humanists UK campaigns that are close to your heart?

I support humanist marriage and particularly admire the work of humanist celebrants, who understand our deep and abiding need for collective joy and collective grief. Having a caring and compassionate person who can help to mark births, marriages and deaths with loved ones, and without religion, is hugely important.