Learnasecondlanguagetoslowageingbrain'sdeclineFeeltoooldortoostupidtolearnasecondlanguage?Itmaybeworthpersevering.AstudythattrackedhundredsofScottishpeoplefordecadesisthestrongestevidenceyetthatspeakinganextralanguageslowsthementaldeclinethataccompaniesageing.ThebenefitsholdregardlessofyourIQandevenifyoulearnyoursecondtongueasanadult.PreviousstudieshaveshownthatpeoplewithAlzheimer'sdiseasewhoarefluentintwolanguagesexhibitsymptomsoftheconditionfourorfiveyearslaterthanpeoplewhoaremonolingual,andthatpeoplewhoarebilingualperformbetterinsomecognitivetests.However,ithasbeendifficulttodisentangletheeffectsofknowingmultiplelanguagefromotherfactors.Forexample,somestudieshavecomparedbilingualimmigrantsandtheirfamilieswithmonolingualnatives.Toresolvetheissue,ThomasBakoftheUniversityofEdinburgh,UK,andhiscolleaguesturnedtotheLothianBirthCohortstudy,whichhastrackedabout1100peoplebornin1936inandaroundEdinburgh.AllweremonolingualEnglishspeakersatage11,whentheyhadtakenabatteryofcognitivetests.Thestudywasn'tdesignedtoinvestigatelanguageeffects.But853oftheparticipantsweretrackeddownwhentheywereintheirearly70s.Ittranspiredthatalmostone-third,or262,ofthemhadlearnedtospeakatleastoneadditionallanguageandthat65hadlearneditaftertheageof18.Asaresult,thestudyprovidesauniqueresearchopportunity,saysEllenBialystokatYorkUniversityinToronto,Canada,whowasfirsttodiscoverthatbeingbilingualdelaystheonsetofAlzheimer's."YouhavethisabsolutelyhomogenoussampleofScottishkids–allmonolingual–andyouletthemgooffandhavetheirlivesandseewhathappens,"shesays.Bak'steamgavetheparticipantscognitivetestsandcomparedthesewiththetestscoresfromwhentheywere11.Thosewhohadlearnedanextralanguageperformedbetterinthecognitivetestsintheir70sthanwouldbepredictedfromtheirearlierscores,indicatingthattheextralanguageitselfisbeneficial.Thestrongesteffectswereongeneralintelligenceandreading.Thisfurthersuggeststhatthebenefitsaredowntotheextralanguage,becauseiftheyweresimplyduetogreaterintelligence,youwouldexpecttheretobeaboostacrossallskills."Forthefirsttimeweaddressthechickenandeggquestion,"saysBak.Histeamfoundthatthebenefitstotheageingbrainwerecomparabletophysicalactivity,ornotsmoking.BialystoksaysthecognitivebenefitsseenintheScottishstudychimewithherownworkonbilingualpeoplewithAlzheimer'sdisease,suggestingthatthesamebeneficialprocessesareatwork.Howcouldlanguagesprotectthebrain?Aleadingtheoryisthatpeoplewhospeakseverallanguagesconstantlyactivatealltheavailablewordsineachonebeforechoosingtheappropriateexpression,givingthemamentalworkout.
