2020 nian 09 yue 30 ri 14:00-16:00.
liuxiaoboshi，qinghuadaxuejingjiyuguanlixueyuanfujiaoshou，meiguomixiegendaxueannabaofenxiaoboshi。zhuyaoyanjiuxingqubaokuogonggongzhengce，boyilun，xinxijingjixue，shiyanjingjixuehexingweijingjixue。tadeyanjiuchengguofabiaozaigames and economic behavior, management science, experimental economics, journal of economic behavior and organizationdengxueshukanwushang，zhuchiguoguojiazirankexuedengduogejijinxiangmu。xiandanrenjournal of behavior and experimental economicsqikanbianweihemanagement science, journal of public economics, experimental economics，games and economic behaviordengduogezhimingqikandenimingpingshen。
gifts are important instruments to bond interpersonal relationships. using 36 million online red packets on wechat, we employ a natural experiment approach to identify in-group contagion of gift giving. we find that, on average, receiving one more dollar causes a recipient to send 18 cents back to the group within the subsequent 24 hours. moreover, this effect is much stronger for "luckiest draw'' recipients, which suggests a group norm for gift giving. additionally, we find that gift contagion is affected by in-group friendship network properties, such as the number of in-group friends and the local clustering coefficient