Estimating Heterogeneous and Hierarchical Peer Effects on Body Weight Using Roommate Assignments as a Natural Experiment
利用大学新生室友随机分配的自然实验，发现女性体重受同伴影响，且影响具有异质性（体重极端者更敏感）和层级性（只受更瘦、社会经济地位更高、性经验更丰富的室友影响）。
We investigate peer effects in weight gain by exploiting a natural experiment, roommate assignments of 751 male and 845 female first-year college students. Results indicate that females are subject to peer influence in weight gain, with little evidence of peer effects for males. Peer influences appear to be heterogeneous as heavier and thinner females are affected by roommates more than average-weight females, and hierarchical with females influenced only by roommates who are thinner, of a higher socioeconomic status, and more sexually experienced relative to themselves. Similarity of academic performance, religiosity, and political views appears to facilitate transmission of peer influences.