The team also discovered that while men and women might harbor regret over the last time an opportunity for casual sex arose, they react differently to that reflection: Men tend to regret not taking advantage of the change for casual trysts – and women tend to regret doing just that.

Researchers from the Norwegian University of Science and Technology’s psychology department studied whether sexual regret contributes to any changes in future behavior. They asked their study participants to complete two questionnaires over an average of 18 weeks and published their findings in Evolutionary Psychology.

“For the most part, people continue with the same sexual behavior and the same level of regret,” said lead author and clinical psychologist Professor Leif Edward Ottesen Kennair.

"A lot of emotions are functional, like disgust that protects against infection and fear that protects against danger. An evolutionary approach has helped us understand anxiety by understanding the function of fear: fight-flight-freeze is about avoiding danger and defending ourselves against it."

The team found that most people believe regret is actually a helpful negative feeling, guiding them not to repeat what they afterwards felt bad about.

However, the research showed that despite how they might intend to behave the next time around, people don’t seem to learn from their remorse, leading the team to say this suggests regret is actually adaptive and changeable, rather than a firm deterrent or impetus.