Is Sexual Debut in Adolescence an Accelerator of Life History Strategy?

Abstract

Extant research supports the hypothesis that biometric indicators of life history (LH) strategy, such as the timing of sexual debut, are calibrated in response to cues sampled early in development (before age 7). Herein, we theorize that the experience of sexual debut itself may further calibrate women’s LH-related behavioral phenotypes across adolescence by modulating subsequent investment in mating effort, which is associated with faster (vs. slower) LH speed. We tested this hypothesis using longitudinal data, which included Q-Sort LH scores at ages 14, 18, and 23, and a report of whether or not sexual debut occurred between ages 14 and 18. Results demonstrated that women (but not men) who experienced their sexual debut between the ages of 14 and 18 showed greater relative acceleration of LH speed during this period than women who had not debuted by age 18. However, these same effects had weakened by age 23—which underscores the broader idea that LH-related behavioral phenotypes exhibit substantial cue-based plasticity across adolescence and into adulthood. Although alternative explanations for the observed patterns remain unfalsified, these findings are consistent with the hypothesis that developmental LH trajectory is regulated in relation to the timing of sexual debut in adolescence. This possibility could be further investigated in future research.