1990 - Sociedade Brasileira de Psicologia

13a
conespondsdirectly to Skinner*s(1935)definition ofastimulusclass.Arbitmry
equivalencehasbeen defined hzavariety of . ways.One definition emphasizesmutual
substitutability hzagiven context(Spmdlin,Coter& Baxley,1973).Sidmnn and Tailby
(1982)argued thatequivalencerelationsshould beevaluated by testing forthe requisite
propertiesspecified in elementary mnthematicstexî (i.e.,reflexivity,symmetry,and
tmnmitivity).Vapghan (1988)suggested anothermAthemnticalderlpition (thepgrtition)
based on settheory.Finaly,Hayes(1990)hasèfered themoregenemlconceptof
'arbitmrily applicable relationalresponding'.W hatappearsto be necessary is the
developmentofacomprehensive,consensusdefmition ofstimultlsequivalence.
W hatKlnd ofStlmullCan Be Equivalent?'
'rhe'se can includeauditory sthnuli(dictatedwords,tones,etc.),visualstimuli
(objeci,pictures,etc.),and stimuliperceived in severalotherways(i.e.,by touch,hste,
and smel).Research to datesuggesi thatone can combineany numberofthesestimulus
typestogenemteequivalencerelations.Fprtherdçmonstration research in thisvein is
probably notahigh priority. . .
How M any StimuliCap BeM em bersofEquivalenceClasses?
Research reported in thepastfew yearshasreported 6-9memberarbitrary
equivalenceclasses(Sidman,Wilson-M oris& Kirk,1985;R.Saunders,K.Saunders,
& Spmdlin,1990).Ifone includesresearch on monetary equivalences(e.g.,Stoddard,
Brown,Hurlbert,Manoli& Mcllvane,1989),thenumberincreasestoatleastdozens.
Research so farhasindicated noupperlimiton thesizeofequivalenceclasses,butitis
possiblethatthis'm'ay proveto be an importàntquantitative variablein the study of
intellectualdisability.
.
g . .'. . .,* . . .'
W hatlstheRelationship Between StlmulusEquivalenceand Language?
Therearp two principalproposals.Sidmnn (in prerxs)sugges? thatstimulus
equivalenceisabasic stimulusfunction,onethatmay providethebasisforlanguage and
othercomplex behaviomlrepertoires.In contrast,Hayes(1990)hasproposed that
equivalence relationsdepend on prioracquisition oflanguage.Currently,one cannot
mnke a data-basedjudgmenton the meritsofthe proposals.Thiswildepend ultimately
on the chamderisticsofsubjectsin whom equivalencerelationsaredemonstmble tsee
below)..
'.
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