A new study published in Evolution and Human Behavior provides evidence that the tendency for young men to mistake friendliness for sexual interest strengthens gradually throughout their teenage years. The research also suggests that when adolescent girls express romantic interest, boys rarely dismiss it as mere friendliness. Together, these findings help explain how romantic misunderstandings develop during adolescence and mirror the dynamics often seen in heterosexual adults. In evolutionary psychology, a framework called Error Management Theory proposes that adults have built up specific biases to handle the uncertainty of dating. This theory suggests that men tend to overperceive sexual interest so they do not miss out on rare mating opportunities. Failing to notice a sexual opportunity carries a high reproductive cost for men. On the other hand, women tend to underperceive sexual interest. This underperception bias helps them gently brush off unwanted suitors without causing conflict and protects their social reputation from rumors. While these patterns are well documented in adults, scientists did not know at what age these psychological adaptations activate. Because adolescents experience …