打哈欠真的会传染吗?人们常说打哈欠会传染，每次你一打呵欠，周围的人也会跟着打哈欠。难道哈欠真的可以传染，还是仅仅是巧合而已？我们来看看神经学家是怎么说的吧！“Ayawnisaninstinctivebehavior：Youdon'thavetolearntodoit，andyawnsareevenpresentbeforebirth.”saysRobertProvine，aprofessorofpsychologyandneuroscienceattheUniversityofMaryland，BaltimoreCounty.Whenweseesomeoneelseyawn，wedon'tthinktoourselves，“Well，I'llyawn，too.”Itjusthappens——it'sinstinctive，andit'saveryprimalaspectofhumanbehaviorthatgoesbacktoancientherdmentality.Adeliepenguins，forinstance，employyawningaspartoftheircourtshipritual.Thehappycouplesfaceoffamidtheicefloesandthemalesengageinwhatisdescribedasan“ecstaticdisplay，”theirbeaksopenwideandtheirfacespointedskyward.Itmaybe，therefore，thatwhenyourentryuponthesceneinspiresaroundofuncontrollableyawning，youhavemerelystumbledontoagaggleofAdeliepenguinsindisguise，whoaresignalingtheirpowerfuleroticlongingforyou.Aslimhope，admittedly，butanyportinastorm.Asforthelargerquestionofwhyyawnsarecatching，nobodyreallyknows.Factis，wedon'tknowwhypeopleyawn.Itwaslongbelievedyouyawnedwhentherewastoomuchcarbondioxideandnotenoughoxygeninyourblood.Apartofyourbraincalledthebrainstemdetectedthis用心爱心专心andtriggeredtheyawnreflex.Yourmouthstretchedwideandyouinhaleddeeply，shootingajoltofoxygenintothelungsandthencetothebloodstream.Subsequently，youexhaledalotofCO2.Oftenyou'dstretchwhileyawning，whichseemedtotemporarilyimprovecirculation.Youyawnedandstretchedalotmorewhenyougottiredbecauseyourbreathingsloweddown.Orsopeoplethought.Inrecentyears，though，afewradicalshavesaidtheprecedingisallmalarkey.Whoknows，theysay，maybeweyawnbecauseit'stoowarmintheroom.Cecilisn'tabouttosettletheissuehere，andhedoesn'tneedto.Wemerelyobservethatwhateveryawn-inducingconditionsprevailforyoualsoapplytoyourfriends.Ifyou'reoutlateinsomecrowdeddive，you'reprobablyalltired，allwarmunderthecollar，andallbreathingthesamestaleair.You'reprobablyallonthevergeofayawn，too，andthepowerofsuggestionfromseeingonepersondoitisenoughtopusheverybodyelseovertheedge.Adultsrarelycatchacaseoftheyawnsfromachildoranimal，whichtendstocorroboratethisidea.Childrenusuallyhavedifferentsleepschedulesandrespirationratesfromadults，soyouwouldexpectthemtoyawnatdifferenttimes.Animals，ontheotherhand，oftenyawnnotforphysiologicalreasonsbutasadisplayofhostility，towhichhumansareevidentlyunresponsive.用心爱心专心malarkey：胡说corroborate：确证，证明unresponsive：无答复的用心爱心专心
