20没有道理的小费

18Gratuitous1Gratuities2Everybodyloathes3it,buteverybodydoesit.Arecentpollshowedthat40％ofAmericanshatethepractice.Itseemssoarbitrary4,afterall.Whydoesabarman5getatip,butnotadoctorwhosaveslives?InAmericaalone,tippingisnowa＄16billion-a-yearindustry.Consumersactingrationallyoughtnottopaymorethantheyhavetoforagivenservice.Tipsshouldnotexist.Sowhydothey?Theconventionalwisdomisthattipsbothrewardtheeffortsofgoodserviceandreduceuncomfortablefeelingsofinequality.Thebettertheservice,thebiggerthetip.Suchexplanationsnodoubtexplainthepurported6originoftipping-inthe16thcentury,boxesinEnglishtaverns7carriedthephrase“ToInsurePromptitude8”(laterjust“TIP”).ButaccordingtonewresearchfromCornellUniversity,tippingnolongerservesanyusefulfunction.Thepaperanalysesdatafrom2,547groupsdiningat20differentrestaurants.Thecorrelation9betweenlargertipsa