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5 More Interesting Things About the Desire for Casual Sex

Sociosexuality is linked to physical characteristics and relationship choices.

Key points

  • Sociosexuality, or the desire for uncommitted sex, can be detected in vocal attributes that differ between men and women.
  • Studies show that sociosexuality may change in women over the menstrual cycle and decline in men over time, particularly after settling down.
  • High sociosexuality is associated with greater use of dating apps like Tinder and a desire for non-monogamous relationships.

Not everyone wants to have sex within a committed relationship. One of my most popular posts from last year looked at five interesting things science had to say about the desire for casual sex (or sociosexuality). Research into sociosexuality is booming, and a lot has happened even in the past year, so I am back with a sequel. Here are five more things we’ve learned about the preference for sex without the strings.

Klaus Nielsen/Pexels
Klaus Nielsen/Pexels

1. It can be detected in the voice.

A recent study using participants from Brazil and the Czech Republic found that sociosexuality is linked to speech attributes, which are different for men and women. Men with lower-pitched speech were seen as more attractive and tended to have a more unrestricted (or higher) sociosexuality. In contrast, women’s desire for casual sex wasn’t related to their voice pitch but their vocal tract length (which influences resonance).

2. Women’s interests (might) change across their menstrual cycle.

A controversial topic within the human evolutionary sciences is whether women’s sociosexuality tracks their fertility status. The logic here is that because pregnancy risk changes across the menstrual cycle, women’s mating psychology should shift accordingly so that if they become pregnant, it’s with the best possible option. For those in close and happy relationships, this would be their current partner, but in other cases, it might be a more attractive prospect outside of their relationship .

Early studies supported this “ovulatory shift hypothesis,” but later, ones with larger sample sizes (including ours) cast doubt over it. The latest research, using direct hormonal tracking and longitudinal data, seems to suggest there’s something there, though the changes seem quite modest.

3. Men’s interest changes as they settle down and become fathers.

It has long been established that testosterone declines with age in men and that this happens more quickly when they become fathers. Now, research has convincingly demonstrated that the same happens with sociosexuality.

A study in the Philippines took almost 300 single and childless men and tracked their sociosexuality over five years. Those who became married and fathers at that time showed a drop in their desire for uncommitted sex, while those who stayed single did not. It appears that settling down has both psychological and hormonal effects on men as they shift from directing their time and effort on mating towards parenting.

4. It draws people towards Tinder rather than

A recent study from Norway found that high sociosexuality predicted greater use of picture-based mobile dating apps like Tinder. These apps emphasize quick decisions about physical attractiveness compared to more traditional dating websites, which give more detail about life circumstances, preferences, and personality.

We know that both sexes tend to prioritise physical attractiveness when choosing casual sex partners, so it seems that those with high sociosexuality use the dating tool best aligned to their priorities. This study reveals an important lesson: Pick your domain carefully. If you are looking for a committed long-term relationship, doing so on apps that appeal to those looking for casual sex is like mate-searching on hard mode.

5. It’s not just about promiscuity.

We have recently completed research about the desire for non-monogamous relationships where one person is able to have sex with multiple partners. This includes polygyny, where a man has a long-term committed relationship with multiple wives or girlfriends, and secret affairs, where someone has a committed partner and a “mistress” (or “mister”) behind their back.

One of the surprising findings for us was that those who had a general desire for uncommitted sex were more open to all types of relationships that weren’t monogamy–though they were slightly less keen if they had to share a partner with someone else.

In conclusion, recent research on sociosexuality, or the desire for casual sex, has revealed a number of interesting insights. These are useful for understanding how our mating psychology and preferences change and for helping us to make informed decisions about the places we go to find the types of relationships we want.


Botnen, E. O., Bendixen, M., Grøntvedt, T. V., & Kennair, L. E. O. (2018). Individual differences in sociosexuality predict picture-based mobile dating app use. Personality and Individual Differences, 131, 67-73.

Gettler, L. T., Kuo, P. X., Rosenbaum, S., Avila, J. L., McDade, T. W., & Kuzawa, C. W. (2019). Sociosexuality, testosterone, and life history status: prospective associations and longitudinal changes among men in Cebu, Philippines. Evolution and Human Behavior, 40(2), 249-258.

Marcinkowska, U. M., Mijas, M., Koziara, K., Grebe, N. M., & Jasienska, G. (2021). Variation in sociosexuality across natural menstrual cycles: Associations with ovarian hormones and cycle phase. Evolution and Human Behavior, 42(1), 35-42.

Thomas, A. G., Harrison, S., Stewart-Williams, S., & Workman, L. (2022). Polygamous Interest in a Monogamous Nation: The Role of Sex and Sociosexuality in Openness to Polygamy in a UK Sample.

Valentova, J. V., Tureček, P., Varella, M. A. C., Šebesta, P., Mendes, F. D. C., Pereira, K. J., ... & Havlíček, J. (2019). Vocal parameters of speech and singing covary and are related to vocal attractiveness, body measures, and sociosexuality: a cross-cultural study. Frontiers in psychology, 10, 2029.

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