For a new paper published in the British Journal of Psychology, a research team lead by Nipissing University psychologist Steven Arnocky got the lowdown on people’s sweetness and sexual history. In one study, the researchers recruited 192 unmarried women and 105 unmarried men from northern Ontario and threw a bunch of autobiographical and psychological examinations their way. The first was an assessment measuring altruism (with items like “I have helped push a stranger’s car out of the snow,” “I have given directions to a stranger,” and the like). Then came several measures of mating success. One was a self-reported desirability scale, with items like “Members of the opposite sex that I like tend to like me back” and “I can have as many sexual partners as I choose.” Then they shared data points like their number of lifetime sex partners, their lifetime number of casual sex partners, and if they were in a relationship, how many times they had sex in the last 30 days. They also took a personality assessment.

After crunching the numbers, the researchers found that altruistic behavior “significantly predicted” self-reported mating success and lifetime number of sexual partners, and that it was “modestly related” with sex within a relationship. The researchers also found that altruism had a stronger link to casual sex partners for men compared to women. In a second study of 335 undergraduate women and 189 undergraduate men, participants did self-reports on desirability, sexual history, and personality. They were also presented with a hypothetical situation: If they were to win a $100 raffle, would they keep the money, donate it to charity, or do some combination of the two? In line with the first study, the second found that donating “significantly predicted” the number of people someone had slept with over their lifetime.