一、短文介绍

Fairandsquare

Somemonkeysseemtohaveahighlydevelopedsenseoffairness

EVERYBODYlovesafatpayrise。Yetpleasureatyourowncanvanishifyoulearnthatacolleaguehasbeengivenabiggerone。Indeed，ifhehasareputationforslacking，youmightevenbeoutraged。Suchbehaviourisregardedasalltoohuman，withtheunderlyingassumptionthatotheranimalswouldnotbecapableofthisfinelydevelopedsenseofgrievance。ButastudybySarahBrosnanandFransdeWaalofEmoryUniversityinAtlanta，Georgia，whichhasjustbeenpublishedinNature，suggeststhatitisalltoomonkey，aswell。

Theresearchersstudiedthebehaviouroffemalebrowncapuchinmonkeys，whichhaveallthenecessaryingredientstocapturethepublicimagination。Theylookcute。Theyaregood－natured，co－operativecreatures，andtheysharetheirfoodreadily。Aboveall，liketheirfinickyfemalehumancounterparts，theytendtopaymuchcloserattentiontothevalueofgoodsandservicesthanmales。

SuchcharacteristicsmakethemperfectcandidatesforDrBrosnan‘sandDrdeWaal‘sstudy。Theresearchersspenttwoyearsteachingtheirmonkeystoexchangetokensforfood。Normally，themonkeyswerehappyenoughtoswappiecesofrockforslicesofcucumber。However，whentwomonkeyswereplacedinseparatebutadjoiningchambers，sothateachcouldobservewhattheotherwasgettinginreturnforitsrock，theirbehaviourbecamemarkedlydifferent。

Intheworldofcapuchins，grapesareluxurygoods。Sowhenonemonkeywashandedagrapeinexchangeforhertoken，thesecondwasreluctanttohandhersoverforamerepieceofcucumber。Andifonereceivedagrapewithouthavingtoprovidehertokeninexchangeatall，theothereithertossedherowntokenattheresearcheroroutofthechamber，orrefusedtoacceptthesliceofcucumber。Indeed，themerepresenceofagrapeintheotherchamberwasenoughtoinducesullenbehaviourinafemalecapuchin。

DrBrosnanandDrdeWaalreportthatsuchbehaviourisunusualintheirtrainedmonkeys。Duringtwoyearsofbarteringpriortotheseexperiments，failuretoexchangetokensforfoodoccurredinfewerthan5%oftrials。Andwhatmadethebehaviourevenmoreextraordinarywasthatthesemonkeysforfeitedfoodthattheycouldsee―andwhichtheywouldhavereadilyacceptedinalmostanyothersetofcircumstances。

Theresearcherssuggestthatcapuchinmonkeys，likehumans，areguidedbysocialemotions。Inthewild，theyareaco－operative，group－livingspecies。Suchco－operationislikelytobestableonlywheneachanimalfeelsitisnotbeingcheated。Feelingsofrighteousindignation，itseems，arenotthepreserveofpeoplealone。Refusingalesserrewardcompletelymakesthesefeelingsabundantlycleartoothermembersofthegroup。However，whethersuchasenseoffairnessevolvedindependentlyincapuchinsandhumans，orwhetheritstemsfromthecommonancestorthatthespecieshad35myearsago，is，asyet，anunansweredquestion。