Bodylanguageisabroadtermforformsofcommunicationusingbodymovementsorgesturesinsteadof,orinadditionto,sounds,verballanguage,orotherformsofcommunication.Itformspartofthecategoryofparalanguage,whichdescribesallformsofhumancommunicationthatarenotverballanguage.

　　Therelationofbodylanguagetoanimalcommunicationhasoftenbeendiscussed.Humanparalanguagemayrepresentacontinuationofformsofcommunicationthatournon-linguisticancestorsalreadyused,oritmaybethatithasbeenchangedbyco-existingwithlanguage.Somespeciesofanimalsareespeciallyadeptatdetectinghumanbodylanguage,bothvoluntaryandinvoluntary:thisisthebasisoftheCleverHanseffect(asourceofartifactincomparativepsychology),andwasalsothereasonfortryingtoteachthechimpanzeeWashoeAmericanSignLanguageratherthanspeech—andperhapsthereasonwhytheWashoeprojectwasmoresuccessfulthansomepreviouseffortstoteachapeshowtodance.

　　Nonverbalcommunication(NVC)isusuallyunderstoodastheprocessofsendingandreceivingwordlessmessages.Suchmessagescanbecommunicatedthroughgesture;bodylanguageorposture;facialexpressionandeyegaze;objectcommunicationsuchasclothing,hairstylesorevenarchitecture;symbolsandinfographics;prosodicfeaturesofspeechsuchasintonationandstressandotherparalinguisticfeaturesofspeechsuchasvoicequality,emotionandspeakingstyle.

　　ThefirstscientificstudyofnonverbalcommunicationwasCharlesDarwin'sbookTheExpressionoftheEmotionsinManandAnimals(1872).Hearguedthatallmammalsshowemotionreliablyintheirfaces.Studiesnowrangeacrossanumberoffields,includingkinesics,linguistics,semioticsandsocialpsychology.Proxemicsreferstohowpeopleuseandinterpretspace.

　　Whilemuchnonverbalcommunicationisbasedonarbitrarysymbolswhichdifferfromculturetoculture,alargeproportionisalsotosomeextenticonicandmaybeuniversallyunderstood.PaulEkman'sinfluential1960sstudiesoffacialexpressiondeterminedthatexpressionsofanger,disgust,fear,joy,sadnessandsurpriseareuniversal.