?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Co-Evolution+of+Language-Size+and+the+Critical+Period&rft.creator=Hurford%2C+James+R&rft.creator=Kirby%2C+Simon&rft.subject=Behavioral+Analysis&rft.subject=Behavioral+Biology&rft.subject=Evolution&rft.subject=Population+Biology&rft.subject=Sociobiology&rft.subject=Evolutionary+Psychology&rft.subject=Historical+Linguistics&rft.subject=Pragmatics&rft.subject=Semantics&rft.subject=Syntax&rft.subject=Philosophy+of+Language&rft.description=Species+evolve%2C+very+slowly%2C+through+selection+of+genes+which+give+rise+to+phenotypes+well++adapted+to+their+environments.+The+cultures%2C+including+the+languages%2C+of+human+communities++evolve%2C+much+faster%2C+maintaining+at+least+a+minimum+level+of+adaptedness+to+the+external%2C+non-+cultural+environment.+In+the+phylogenetic+evolution+of+species%2C+the+transmission+of+information++across+generations+is+via+copying+of+molecules%2C+and+innovation+is+by+mutation+and+sexual++recombination.+In+cultural+evolution%2C+the+transmission+of+information+across+generations+is++by+learning%2C+and+innovation+is+by+sporadic+invention+or+borrowing+from+other+cultures.+This++much+is+the+foundational+bedrock+of+evolutionary+theory.+But+things+get+more+complicated%3B+there+can+be+gene-culture+co-evolution.+Prior+to+the++rise+of+culture%2C+the+physical+environment+is+the+only+force+shaping+biological+evolution+from++outside+the+organism%2C+and+cultures+themselves+are+clearly+constrained+by+the+evolved+biological+characteristics+of+their+members.+But+cultures+become+part+of+the+external+environment%2C+and++influence+the+course+of+biological+evolution.+For+example%2C+altruistic+cultures+with+developed++medical+knowledge+reduce+the+cost+to+the+individual+of+carrying+genes+disposing+to+certain++pathologies+(such+as+diabetes)%3B+and+such+genes+become+more+widespread+in+the+populations+maintaining+such+cultures.+Assortative+mating+can+affect+biological+evolution%2C+and+particular+cultures+may+influence+the+factors+which+are+sorted+for+in+mating.+(For+a+careful+discussion+of++the+effects+of+cultural+evolution+on+natural+selection%2C+see+Cavalli-Sforza+and+Bodmer%2C+1971%3A774-+804).++This+paper+examines+mechanisms+involved+in+the+co-evolution+of+a+biological+trait%2C+the++critical+period+for+language+acquisition%2C+and+a+property+of+human+cultures%2C+the+size+of++their+languages.+A+gene%2Fculture+interaction+will+be+shown+that+can+be+described+as+a+kind+of++symbiosis%2C+but+perhaps+more+aptly+as+an+%60arms+race'.+In+this+introduction%2C+we+will+sketch+the++basic+mechanics+of+the+interaction+in+very+broad+terms%3B+the+rest+of+the+paper+will+explain+and++justify+the+details.+The+implications+of+our+model+for+second+language+acquisition+are+given++toward+the+end+of+the+paper.&rft.publisher=Lawrence+Erlbaum&rft.contributor=Birdsong%2C+David&rft.date=1998&rft.type=Book+Chapter&rft.type=PeerReviewed&rft.format=application%2Fpostscript&rft.identifier=http%3A%2F%2Fcogprints.org%2F164%2F2%2Fbirdsong.s.ps&rft.identifier=++Hurford%2C+James+R+and+Kirby%2C+Simon++(1998)+Co-Evolution+of+Language-Size+and+the+Critical+Period.++%5BBook+Chapter%5D++++(Unpublished)++&rft.relation=http%3A%2F%2Fcogprints.org%2F164%2F