Gary L. Brase, Lora Adair and Kale Monk of the Kansas State University asked almost 500 young adults -- half men, half women with a median age 19 who were 83 percent white -- to complete several questionnaires on a several topics, including relationships and cheating.
For example, they were asked: "Which would distress you more: Imagining your partner enjoying passionate sexual intercourse with another person or imagining your partner forming a deep emotional attachment with another person?”
Fifty-eight percent of men said it was more distressing for a partner to have sexual intercourse for just one night versus being emotionally involved with another person, with no chance of sex.
"Although these two types of infidelities can occur together, the distinction created by a forced choice methodology can provide insight into which of these types of infidelity is relatively more distressing and reveal patterns of responding that can inform evolutionary predictions about sex differences in sexuality and parental investment," the study said.
The findings were published in the journal Evolutionary Psychology.