Australasian Science: Australia's authority on science since 1938

How a Woman’s Fertility Affects Men’s Speech

By Magdeline Lum

Men become more creative in their conversations when they detect subtle signals that a woman is fertile.

Romantic candlelit dinners for two and couples embracing in parks seem ideal from afar, but what we can’t hear is the stumbling of phrases during declarations of love. What can be more frustrating than to sound like a bumbling fool instead of appearing suave and debonair? It may be wiser to keep things simple but this is easier said than done.

A study led by A/Prof Michael Kaschak of Florida State University in Tallahassee has found that when young heterosexual men are around fertile women they are more likely to be creative with their sentence structure. The study states that men are responding to small changes in facial skin tone, vocal pitch and the scent of women in the fertile period of their menstrual cycles.

When two people talk to one another they usually mirror each other in the way they speak to each other, but what researchers found in the study, published in PLoS One, was that men speaking with fertile women spoke differently and were more likely to stand out.

One experiment studied 123 male undergraduate university students from Florida State University interacting with five female undergraduate students who were not taking hormonal contraceptives during different times of their menstrual cycles. Each male student was allowed to interact with a female student to enable some familiarity with each other before commencing set tasks. The female students were under instruction to keep the conversation at a minimum and to remain neutral with expressions and remain polite and to not show too much interest in the participant. This interaction occurred at the same desk while being seated close to one another.

After a few minutes they were separated and sent to desks separated from one another by a divider. The male and female student pairs were then given the task of describing pictures to one another.

Each participant was given two stacks of pictures: one was a description stack and the second stack was a matching stack. They took turns describing the pictures to one another using a single sentence and the verb at the top of the picture. The listener’s task was to find the matching picture in the matching stack. The female participant was the one who always started the activity.

The researchers found that when the female participant was at the low point of fertility of their menstrual cycle, the male participants mirrored their sentence structures 62% of the time. But when the female participant was at her peak of fertility of their menstrual cycle, the rate of mirroring sentence structure fell to 49.7% of the time. These results reflect the notion that men may do something different to stand out to women.

However, male participants in the study who thought their female partner was being flirtatious were more likely to match their speech patterns to her. This is in line with research suggesting that conversations between attracted partners lead to speech patterns that increase in matching patterns.

The research team repeated this experiment using only heterosexual female participants, but no effect was found on sentence structure. Researchers concluded that the effect was specific to heterosexual men.

“At least a part of the interpersonal dynamic that exists when men and women are getting to know prospective romantic partners is being governed by the biology of a woman’s body and men’s sensitivity to these biological factors,” Kaschak says.

Kaschak and his co-author concluded that their findings will be of interest to linguists interested in cognitive and social approaches to language. For the rest of us, however, it serves as a reminder that there is a lot happening in the conversations between men and women.