The article is titled, "Casual Contraception in Casual Sex: Life-Cycle Change in Undergraduates' Sexual Behavior in Hookups" by Jonathan Marc Bearak (New York University). The article provides reasoning for the decline in the use of condoms, and explains how changes in the odds of coitus and condom use depend on family background, school gender imbalance, and whether the partners attend the same college.
The results show that the odds of unprotected intercourse in hookups doubles between freshman and senior year. Among the factors which contribute to this, freshmen from less advantaged socioeconomic backgrounds more frequently protect themselves with a condom when they have intercourse in a hookup than freshmen from more advantaged backgrounds, but by sophomore year, they adopt the same lower condom use rate of their peers from more advantaged backgrounds.
These results are consistent with the view that college is perceived as a safer environment. An interpreta¬tion equally consistent with the data is that it may take longer for lower socioeconomic status students to integrate into the social activities on their campus, which, conceiv¬ably, may not encourage condom use. This research also highlights an oft-overlooked issue in sexual research: the probability of intercourse within the normative contexts in which adolescents and young adults sexually interact contributes to cumulative risks over and above their contraceptive practices.