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Does the effort you invest in seeking a romantic partner intensify as summer ends? During the colder, darker months, people have been known to engage in "cuffing season," which means attaching yourself to or having a physical relationship with someone just for the cold winter months.

You know this is not going to be a long-term thing. "Cuffing" is a metaphor for wanting to be attached to someone for a period of time. In the northern hemisphere at least, such behavior might begin around October and end close to Valentine's Day. Dating apps such as Bumble and Hinge have reported that October and November often sees a surge in new profiles and messaging activity.

In our evolutionary past, cuffing may have been necessary for survival. The winter months are cold and dark, and it would have been adaptive for our ancestors to seek out the company of others to keep them warm and safe, over a period when they could perish from exposure, or be more vulnerable to attack from predators. The company of others would have provided warmth, and possibly someone to help protect them.

Cuffing behavior might also be explained, at least for men, by a variation in testosterone levels. These tend to be lower in the months with the highest temperatures and most daylight, and higher in the winter months. This increase in men's testosterone levels during the winter months might cause an increase in efforts to seek out the company of a sexual partner.

Polish researchers Buguslaw Pawlowski and Piotr Sorokowski have noted that men's judgements of female attractiveness varied seasonally. In their 2008 study, 114 heterosexual men were asked to assess the attractiveness of women's photographs over different seasons. The photographs featured waist-hip ratio variations of women in swimming suits, photos of female breasts and photos of average-looking faces of women. The researchers found changes in male preferences for body shape and breast attractiveness across the seasons, although there was no change in men's ratings of female faces.

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