Prinz sobre modularidad

8/10/2019 Prinz sobre modularidad

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CHAPTER

T W O

Is the Mind Really Modular?

Jesse J. Prinz

When Fodor titled his (1983) book the Modularity of Mind, he overstated his posi-

tion. His actual view is that the mind divides into systems some of which are modu-

lar and others of which are not The book would have been more aptly if less

provocatively called The Modularity of Low-evel Peripheral Systems. Highlevel perception and cognitive systems are nonmodular on Fodors theo. n recent years

modularity has found more zealous defenders who claim that the entire mind divides

into highly specialized modules. This view has been especially popular among evolu-

tionay psychologists. They claim that the mind is massively modular Cosmides and

Tooby 1994 Sperber 1994 Pinker 1997; see also Samuels 1998) Like a Swiss army

knife the mind is an assembly of specialized tools each of which has been designed

for some paricular purpose My goal here is to raise doubts about both peripheral

modularity and massive modularity. To do that, will rely on the criteria for modu-

larity laid out by Fodor (1983). will argue that neither input systems nor centralsystems are modular on any of these criteria.

Some defenders of modularity have dropped parts of odors defition and

defed modularity with reference to a more restricted list of features Carrthers

chapter 1 THE CASE FOR MASSELY MODULAR MODELS OF MIND) makes such a move. My

arguments against modularity threaten these accounts as well. My claim is not just

that Fodors criteria are not jointly satisfed by subsystems within the mind but they

are rarely satisfed individually. When we draw boundaries around subsystems that

satis any one of Fodor's criteria for modularity we fd at best, scattered islands

of modulaity. If modules exist they are few and far between. The kinds of systems

that have been labeled modular by defenders of both peripheral and massive mod

larity probably dont quali Thus modularity is not a vey usel construct in doing

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1 Fodor's Criteria

Modularity should be contrasted wth the uncontroversal assumpton of nctonaldecomposton the mnd contans systems that can be dstngushed by the nc-tons they carry out. The modularty hypothess s a clam about what some of the

systems underlyng human competences are le. Fodor characterzes modularty byappeal to nne specal propertes. He says that modular systems are

Localzed modules are realzed n ddcated neural archtecture;2 Subject to characterstc breadowns odules can be selectvely mpared; Mandatoy modules operate n an automatc way4 Fast modules generate outputs ucly;5 Shallow modues have relatvely smple outputs eg., not judgments) ;6 Ontogenetcally determned modules develop n a characterstc pace and

sequence;7 Doman specf modules cope wth a restrcted class of nputs;8 Inaccessble hgher levels of processng have lmted access to the representa-

tons wthn a module;9 Informatonally encapsulaed modules cannot be guded by nformation at hgher

levels of processng

Fodors crteia can be nterpreted n dfferent ways Perhaps a system s modular tothe extent that t exhbts popertes on the lst Alternatvely, some of the proper-

tes may be essental, hle others are merely dagnostc In recent wrtngs Fodor2000) has treated nformatonal encapsulaton as a sine qua non for modulartyDefenders of massve modalty focus on doman specfc n ontogenetc determna-ton Cosmdes and Tooby, 1994; Sperber 1994). I wll emphasze these propertesn what follows but I wll also dscuss the other propertes on the lst, because, evenf they are not essental, Fodor ples that they cluster together. I am septcal.I thnk the properes on Fodors lst can be used nether jontly nor ndvdually tocrcumscrbe an nterestng class of systems.

2 Localization and Charaeristic Breakdowns

The ft two tems n Fodos account of modularty localzaton ad characterstcbreadowns are closey related. The clam that mental facultes are localzed ssupported by the fact that focal bran lesons cause selectve mental defcts Furtherevdence for localzaton comes from neuromagng studes, whch purpor to pn-pont te bran areas that are actve when healthy dvduals perform mental tass

The edence for anatomcal localzaton seems overhelmng at ft, but prob-lems appear on closer analyss. Utal 200 1 ) ponts out that there s consderable nconsstency across laboratores and studes For example, there s lttle agreement aboutthe precse locaton o f Brocas area, the alleged center of language producton Poeppel1 996) . Indeed, aspects of language producton have been located n every lobe of the

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brain ulvermler, 1999. Or consider vision. There is considerable debate about thelocation of systems involved in processing things as ndamental as space and coorUtta also points out that neuroimaging studies oen implicate argescale networs,rather than small regions, suggesting that vast expanses of corex contribute to manyndamenta tass Sometimes the size of these networs is underestimated By focus-

ing on hotspots, researchers oen overoo regions of the brain that are moderateyactive during tas performance.

Lesion studies are mired by simiar problems. Welnown defcits, such as visualneglect, are associated with lesions in entirey different pars of the brain e.g., frontaeyefeds and inferior parietal corex). Sometimes, esions in the same area have dif-ferent effects in different people, and all too oen neuropsychologists draw generaconcusions from individual case studies This assumes localization rather than pro-viding evidence for it Connectionist models have been used to show that focal lesionsca lead to specif defcits even when there is no localization of functions: a mas-

sivey distributed artifcia neural newor can exhibit a selective defcit aer a fewnodes are removed simulating a foca esion), even though those nodes were not theocus of the capacity that is lost laut, 1 99 5 . More generaly, when a esion eads toan impairment of a capacity, we do not now if the ocus of the lesion is the neuracoelate of the capaci or the correate of some ancilla prerequisite for the capacity

do not want to exaggerate the implications of these considerations There is prob-ably a fair degree of locaization in the brain No one is tempted to defend Lashleys(1950 equipotentiality hypothesis, according to which the brain is an undifferen-tiated mass. But the rejection of equipotentiaity does not suppor modularity.Defenders of modularity combine ocalization with domain specifity they assumethat brain regions are excusivey dedicated to specif nctions. Cal this stronglocalization f, in reaity, mental nctions are located in largescae overlappingnetwors, then it woud be misleading to ta about anatomica rgions as modues

Evidence for strong ocaization is diffcult to come by Simiar brain areas areactive durng multiple tass, and foca brain esions tend to produce mutipe defcits.For exampe, aphasia patients regulary have impairments unreated to language Bates,994 Bates et a., 2000 Even genetic anguage disorders specif language impairments) are comorbid with nonlingusitic probems, such as impairments in rapid aud-ito processing or oro facial contro Bishop, 1992 ; Varghahadem et a., 1995 Taal

et al, 1996.To tae another example, consider the discussion in Stone et a. (2002 of a patin

who is said to have a seective defcit in reasoning about socia exchanges. This patientis aso impaired in recognizing faux pas and mentastate terms, so he does notsuppo the existence of a socia exchange modue Nor does this patient supporthe existence of a general social cognition module, because he performs other socialtass wel.

In sum it is diffcult to fd cases where specif brain regions have trly specifcnctions. One coud escape the locaization crterion by defing modules as motley

assotments of abiities eg, syntax pus oro facia control; social exchange plus fauxpas), but this would trviaize the moduarity hypotesis. There is ittle evidence thatthe capacities presumed to be modular by defenders of the moduarty hypothesis arestrongly ocalized

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3 Mandatory, Fast, and Shallow

The next three tems on Fodors characterzaton of modles are spposed to captrea dstnctve style of processng. Modles he says are mandato, fast, and shallow. dont thn that these properes captre an nterestng class of systems wthn the

mnd. There s lttle reason to thn they are ntmately related to each other. A sys-tem whose processes are mandatory e, atomatc) need not be fast For example,consder the system nderlyng crcadan rhthms, whch reglate the sleepwae cycle.Nor shold we expect mandatory processes to be shallow Semantc prmng s man-dato, bt t taps nto concepal nowledge The three properes nde consderatonare more of a grab bag than a coherent constellaton

The three propertes are nnterestng when consdered n solaton. Consderatomatcty Eveone agrees that some mental processes are atomatc, bt mostmental capactes seem to ntegrate atomatc processes wth processes hat are con-

trolled. For example, we form syntactc trees atomatcally bt sentence prodctoncan be controlled by delberaton Lewse, we see colors atomatcally, bt we canvslly magne colors at wll. The atomatc/controlled dstncton cannot be sedto dstngsh systems n an nterestng way

Now consder speed As remared above, some capactes that loo le plasblecanddates for mental modles may be slow e.g., those goveng crcadan rhythms)n addton, there are large varatons n performance speed wthn any general system,sch as vson or langage. Verb conjgaton, for example, may depend on whether theverb n qeston s reglar or rreglar and whether the verb s freqent or nfreqent.There s lttle nclnaton to say that verb conjgaton s more modlar when t saccomplshed more qcly. n addton, some of the worst canddates for modlar pro-cesses are relatvely fast prmng s nstantaneos bt t can ln elements n entrelydfferent systems the smell of coee may evoe memoes of a holday n Rome)

Fnally, consder the sggeston that modles have shallow otpts. Shallow ot-pts are opts that do not reqre a lot of processng As an example, Fodor sg-gests that t doesnt tae the vsal system mch processng to otpt representatonsof basc categores e.g., apple, char, car) Bt how mch processng s too mch?There s a lot of processng between retnal stmlaton and vsal recogntonand far fewer steps n ceran hgher cogntve processes, whh Fodor regards as

nonmodlar e.g., t taes one step to nfer fscal conseratve om Repblcan).To get arond ths dffclty, one mght restrct shallow otpts to nonconceptalotpts. Carrthers chapter 1) rghtly complans that ths wold beg the estonaganst defenders of massve modlar they clam conceptal tass are modlar.

Deftons of shallowness are ether too nclsve or too exclsve. t s not a se-l constrct for dvdng p the mnd.

4 Ontogenetic Determinism

Fodor mples that modles are ontogentcally determned they develop n a predct-able way n all healthy ndvdals. Modles emerge throgh the matraton, rather

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As a fal example wa o cosider language. will keep m remarks briefbecause have criicized he evidence for a innae laguage facul elsewhere Priz2002 see also Scholz ad Pullum chaper 4 IRRATIONAL NATIST EXUERANCE). resricmself o a brief commen o he allegaio ha laguage emerges o a fxed sched-ule. seems for example ha children reliabl begin o lea words beween 8 ad10 mohs ad he begin o combie words around 18 monhs. These numbers doo suppor inaeess. The are saisical averages ha belie eorous variaio.Baes e al. 1995) foud ha in earl word comprehesion age accoued for ol6 perce of he variace and idividual differeces were huge. n a sample ofmoholds he repored umber of words kow raged om 0 o 144. Among18moholds Baes e al. foud ha 46 perce combied words someimes and1 1 perce did so frequenl. The rae of leaig ma deped o facors such asgeneral cogiive developme ad worig memor spa e.g. Seug ad Chapma2000). f he rae of language acquisiio is variable ad correlaed wih nolinguisic

facors he i is bad evidece for inaeess.

presenig hese examples have bee ring o show ha he evidecefor inaeess has bee exaggeraed. The developmenal rajeco of man mealcapaciies is consisen wih a leaing sor. do mean o sugges ha we lackspeciazed capacies. Specialized capaciies ca be leaed. This has been demosraed b recen work o compuaional modelig Jacobs 1999). For exaple oeclass of coeciois models works o he priciple ha ipus will be processedi he porion of he ework ha makes fewes errors whe processing he rai-g daa Usig such a model Thomas ad KarmiloffSmih 2002) demosraeha a ework raied o form pasense verbs from heir presenense forms will

spoaneousl produce a subcomponen ha hadles regular verbs ad aoher subcomponen ha handles irregulars. Their ework has one pahwa wih hree laersof unis ad aoher pahwa wih o. The olaer pahwa is beer wih regularsad he reelaer pahwa is beer wih irregulars because irregular edigsare o liearl separable These wo pahwas are o ask specifc before rainigbu he ed up beig ask specif aerards Such o examples show ha weca easil acquire specialized subssems hrough leaing. Tha meas here is oreason o expec a iimae lik beween innaeness and specializaio Oce halik is broke he role of iaeess in defendig modulari is cas io doub.

5 Domain Specifici

Domain specifi is closel relaed o iaeess To sa ha a capaci is iaeis o sa ha we are biologicall prepared wih ha specif capaci. ae enailsdomai specifc. Bu as we have jus seen domain specifc does o eail inae .Therefore i arguing agais he iaeness crierion of modulari have o udermied he domai specifci crierio. Domai specifci is regarded b some as heessence of modulari and i deseres carel cosideraio.

is dicul o assess he claim ha some menal ssems are domain specifcwihou clariig defiions. Wha exacl is a domain"? Wha is specifci"?O some inerpreaios domai specifci is a rivial proper. Domai ca be

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inerpreed as a snonm for subjec maer. To sa ha a cogniive ssem conces a domain on his reading is o sa ha he ssem has a subjec maer. Thesubjec maer migh be a class of objecs in he world a class of relaed behaviorsa skill or an oher coheren caegor. On he weak reading jus abou anhingcan quali as a domain. Consider an individual concep such as he conce camel.A menal represenaion used o caegorize camels is specifc o a domain since camelsare a coheren subjec maer. Likewse for ever concep.

Specifci also has a weak reading. In saing ha a menal resource is domainspecif we ma be saing no more han ha is i is used o process infoa-ion underling our apiude for ha domain. In oher words domain specifciwould no require exclusivi Consider he capaci o hrow crumpled paper ino awasebaske. Presumabl he menal resources underling ha abili overlap wihresources used in hrowing baskeballs in hoops or hrowing in cans ino recclebins. On he weak defniion of specifci we have a domain specif capacifor hrowing paper ino wasebaskes simpl in virue of having menal resources

underling ha capaci regardless of he fac ha hose resources are no dedicaedexclusivel o ha capaci

Clearl defenders of domain specifci wan somehing more. On a sronger reading domain" refers no o an subjec maer bu o maers ha are relaivelencompassing. Camels are oo specif. The class of animals migh quali as a domainbecause i is more inclusive. Pschologiss have his kind of caego in mind whenhe alk abou basic onological domains" Bu noice ha he sronger defniionis hopelessl vague. Wha does i mean o sa domains are relaivel encompassing?Relaive o wha? Camel is an encompassing concep relaive o he concep: he

paricular animal used b Lawrence o cross he Arabian deser. Moreover i is common in cogniive science o refer o language mindreading and social exhange asdomains. Are hese hings encompassing in he same sense and o he same degreeas animal? In response o hese diffculies soe researchers defne domains asses of principles. This won help. We have principles underling our knowledge ofcamels as well as principles underling our knowledge of animals. I see no escape.If we drop he weak defniion of domain domain = subjec maer) we sill fndourselves wih defniions ha are vague or insuffcienl resricive.

Things are slighl beer wih specifci. On a srong reading specif eansexclusivel dedicaed. To sa ha modules are domain specif is o sa ha he areexclusivel dedicaed o heir subjec aer This is a usefl explanaor consrucand i ma be applicable o cerain menal ssems. Consider he columns of cells inprimar visual corex ha are used o deec edges. These cells ma be dedicaed oha fncion and nohing else. Perhaps modules are supposed o be like ha.

There is sill some risk of riviali here. We can show ha an collecion of rulesand represenaions in he mindbrain is dedicaed b simpl lising an exhausivedisjuncion of everhing ha hose rules and represenaions do. To escape riviali we wan o rle ou disjuncive liss of fncions. We sa ha ssems are domainspecif when he domain can be specifed in inuiivel coheren wa. Les assume

for he sake of argumen ha his requiremen can be made more precise. The problem is ha alleged examples of modules probabl aren domain specif in his srongsense.

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Cosider visio Edge deecors ma be domai specic bu oher resources usedfor processig visual iformaio ma be more geeral For example he visual ss-em ca be recruied i problem solvig as whe oe uses imager o esimae wherea caro of milk ca squeeze io a crammed refrigeraor Some of our cocepualkowledge ma be sored i he form of visual records We kow ha damage ovisual areas ca disrup cocepual compeece Mari ad Chao 200 1 ) . have also

oed ha whe people lose heir sese of sigh areas oce used for visio ge usedfor ouch Visuall perceived simuli also geerae acivi i cells ha are bimodalThe ver same cells are used b he ouch ssem ad he audior ssem f weexcluded rules ad represeaios ha ca be used for somehig oher ha deriv-ig iformaio from ligh he boudaries of he visual ssem" would shrikcoderabl A he eural level of descripio i is possible ha ol isolaedislads of cells would remai This would be a srage wa o care up he midOe of he impora higs abou our seses is a he ca mooligh The cahelp each oher ou ad he ca pla a ceral role i he performace of cogiive

asks Visio ake as a cohere whole is o domai specif i he srog seseeve if i coais some rules ad represeaios ha are

Similar coclusios ca be draw for laguage have said ha laguage mashare resources wih ssems ha sere oher cios: per recogiio musclecorol ad so o B rocas area seems o coai mirror euros whih pla a rolei he recogiio of maual acios such as pichig ad graspig Heiser e a2003). Weices area seems o coai cells ha are used i he caegorizaio ofoliguisic souds Sagi e a 2003) Of course ere ma be some laguage-specif rles ad represeaio within he ssems ha coribue o laguage Perhaps

he euros dedicaed o cojugaig he verb o be" have o oliguisic c-io Such highl localized isaces of domai specici will offer lile comfor ohe defeder omodulari The are oo specif o correspod o modules ha havebee proposed Should we coclude ha here is a module dedicaed o he cojuga-io of each irregular verb?

There is relaivel lile evidece for largescale modules if we use domaispecifci as he crierio I is hard o fd ssems ha are exclusivel dedicaedo broad domais Visio ad laguage ssems are o dedicaed i he srogsese ad he same is rue for oher alleged modules Cosider midreadigwhich clearl explois domai geeral capaciies oed above ha midreadig

is correlaed wih laguage skills Hale ad TagerFlusberg 2003) foud hapreschoolers who failed he false belief ask were more likel o succeed aer receiv-ig raiig i seeial compleme clauses The we from 20 perce correci aribue false beliefs o over 75 perce correc Midreadig also depedso workig memor Performace i atribuig false beliefs is impaired i healhsubjecs whe he are give a urelaed workig memor ask McKio adMoscovich upublished) euroimagig sudies midreadig is show o recruilaguage ceers i le froal corex visuospaial areas i righ emporalpariealregios he amgdala which mediaes emoioal resposes ad he precueus which

is ivolved i meal image ispecio ad ask swichig shor midreadigseems o exploi a large etwork of srucures all of which coribue o ma ohercapaciies

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This seems to be the geeral patte for alleged modules The brai structures ivolvedi mathematical cogitio are also ivolved i laguage spatial processig adatetio Dehaee 1997; Simo 1997). Folk phsics seems to rel o multiobjectattetio mechaisms Scholl ad Leslie 1 999) . Moral judgmet recruits ordiaremotio ceters Greee ad Haidt 2002).

For all I have said alleged modules ma have domai specifc components. erhapsthese sstems use some proprieta rules ad represetatios. But the dot seemto be proprietar throughout. Therefore domai specifcit caot be used to tracethe boudaries aroud the kids of sstems that modularists have traditioall dis-cussed.

6 Inaccessibiliy and Encapsulaion

The fal to properties o Fodors list are closel liked. Modules are said to beiaccessible ad ecapsulated That meas the dot let much iformatio out adth dot let much iformatio i. Fodor thiks the latter propert is especiall impor-at Carruthers places emphsis o both ecapsulatio ad iaccessibilit I thikeither propert is especial usel i carvig up the mid

Lets begi with iaccessibilit Fodor claims that sstems outside a module haveo access to the iteal operatios withi that module This seems plausible itro-spectivel. I have o itrospective access to how m visual sstem achieved colorcostac or how m stax sstem parses seteces. Nisbett ad Wilso 1977) haveshow that huma judgmet is ofe drive b processes that operate below the level

of cosciousess. Does this cofrm that operatios withi modules are iaccessible?No: it shows ol that we lack coscious access. It tells us othig about whetheroperatios withi ucoscious metal sstems are accessible to other ucoscioussstems. For all we kow there ma be extesive accessibt below the level ofawareess.

This is where Carruthers comes i. He has a pricipled argumet for the coclu-sio that metal sstems are b ad large iaccessible He sas that i order for oesstem to access iformatio i aother the rst sstem would eed to represethow the other sstem works. But that meas it would eed to represet all the rules

ad represetatios of that other sstem. This would defeat the purpose of dividigthe mid ito separate sstems ad it would lead to a combiatoal explosio.Therefore most sstems must be iaccessible to each other

am ot persuaded b this argumet It rules out the view that all sstems arecopletely accessible to all others but it does othig to refte the possibilit thatsome sstems have some access to others. For example coceptual sstems mighthave access to stactic trees but lack access to subtle trasformatio rules used iderivig those trees. Limited accessibilit would ot lead to a combiatorial explo-sio ad it might be usel for some sstems to have a idea what other sstemsare doig B aalog the residet caot aed ever cabiet meetig but it wouldhelp him to have some idea of how cabiet members reached a give decisio.

Let me tu from iaccessibilit to ecapsulatio the fal item o Fodors listad for him the most importat. Fodor tries to prove that perceptual sstems are

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modular by appealing to perceptual illusions The interesting thing about illusions

is that they persist even when we know that we are being deceived. The two lines

in the MllerLyre illusion appear different in length even though we know they are

they same. f perception were not encapsulated then the illusion would go away as

soon as the corrective judgment is formed. Belief would correct experience.

Fodors argument is awed There are competing explanations for why illusionspersist. One possibility is that perception aways trumps belief when the two come

into conict Such a trumping mechanism would be advantageous because other

wise, we could not use experience to correct our beliefs. The trumping mechanism

is consistent with the hypotesis that perception is not encapsulated Beliefs may be

able to affect perception when the two are not in conict. To test between trump

ing and encapsulation we need to consider such cases. Consider ambiguous fIgures

Verbal cueing can lead people to alter their experence of the duckrabbit. Likewise

we can electively experence a Necker cube as facing right, facing le, or as a gem-

stone facing directly forard n paintings that covey depth by scale we can see

gures in the distance as far away or we can see them as tiny people oating in the

foreground.

There are many other examples of topdown effects [i.e., cases in which systems

at a relatively advanced stage of processing exert inuence on systems that are involve

in earlier stages of processing). For example, expectations can lead us to experience

things that aren't there. f you are waiting for a visitor, every little sound may be

mistaken for a knock on the door. Or consider visual search: when looking for a

Kodak fIlm carton, small yellow objects pop out in that visual feld. The most obvi

ous case of topdown inuence is mental imagery Cognitive states can be used to

actively construct perceptual representations (Kosslyn et al. 1 995) . This makes senseof the neuroanatomy: there are dense neural pathways from centers of higher brain

nction into perception centers.

There is also evidence for top downeffects in language processing. Defenders of

modularity would have us believe that language divides into a number of modular

subsystems including syntax, semantics, and phonology These subsystems are

alleged to be imperious to each other, but there is empirical evidence to the con

tra For example, in the penomenon of phoneme restoration, subjects are presented

with sentences containing deleted phonemes but, rather than hearing an acoustic

gap the missing phoneme is fIlled in. mportantly the phoneme that is heard is determined by the semantic interpretation of the sentence (Warren and Wrrn, 1 970) .

f subjects hear, The _eel is on the axel they experience a w sound in the gap.

f they hear The eel is on the orange, they experience a p sound

There is also evdence that syntax can be affected by conceptual knowledge Marslen

Wilson and Tyler (1987) showed that conceptual factors exert highly specifI in

ences on sentence completion and they do so at the same speed as lexical factors.

n one experiment subjects are given the following story: As Philip was walking

back from the shop he saw an old woman trip and fal at on her face in the street.

She seemed unable to get up again. The story then continues with one of two

sentence fragments: either He ran toward . . . or Running towards . . ." n both

fragments the appropriate next word is her, but in the ft case that choice in

determined lexically by the prior pronoun in the sentence (he) and in the second

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case that choice is determied concepually we kow that people caot ru whethe are lig dow). Remarkabl subjects are primed to use the word her" equallfast i both coditios If lexical processig were ecapsulated from coceptual pro-cessig oe would expect lexicall determied word choices to arise faster Theseresults impl that foal aspects of laguage are uder immediate ad costat iece

of geera world kowledgeThus far have bee talkig abou topdow iueces o iput sstems. There

is aso evdece that iput sstems ca speak to each other This is icompatible withecapsulatio because a trl ecapsulated sstem would be isulated om any exter-al iuece. Cosider some examples. First whe subjects hear speech souds thatare icosistet with obsered mout movemets the visual experiece sstematic-all distorts the auditor experece of he speech souds McGurk ad MacDoald1976). Secod Ramachadra has developed a therapeutic techique for treatig pha-tom limb pai i which amputees use a mirror reectio to visuall relocate a itact

limb i the locatio of a missig limb; if the scratch or sooth the itact limb thediscomfort i the phatom subsides Ramachadra et al 1 995) . Third soud cagive rise to touch illusios: hearig multiple toes ca make people feel multipletaps whe there has bee ol oe Httig ad Rder 2004). Fiall people withseshesia experiece sesatios i oe modalit whe the are stimulated i ather;for example some people see colors whe the hear souds ad others experieceshapes whe the taste certai avors. All these examples show that there ca bedirect ad cotetspecifc crosstalk betwee the seses

The empirical evidece suggests that metal sstems are ot ecapsulated Butthe sto caot ed here. There is also a pricipled argumet for ecapsulatiowhich is icel preseted b Carruthers. It goes like this metal processes must becomputatioall tractable because the mid is a computer ad metal procsses arecarried out successll i a fite amout of time; if metal processes had accessto al the iformatio stored i the mid i.e. if the were ot ecapsulated) thewould ot be tractable merel checkig cosistec agaist a couple hudred beliefswould take billios of ears); therefore metal processes are ecapsulated

Carruthers recogizes that there is a major aw i this argumet. Accordig tothe secod premise meal processes would be itractable if the had access to allthe iformatio stored i the mid. This is actuall false. Compuatioal sstems ca

sort through stupedousl large databases at breaeck speed. The trick is to usefrugal search rules. Frugal rules are oes that radicall reduce processig load bexploitig simple procedures for selectig relevat items i te database. Oce themost reevat items are selected more thorough processig of those items ca begiPschologists call such simple rules heuristics" Kahema et al 1 982) There isovehelmig evidece that we make regular use of heuristics i performig cogit-ive tasks. For example suppose ou wat to guess which of to cities is larger Hamburgor Maiz. You could tr to collect some populatio statistics which would take alog time) or ou could just pick the cit ame that is most familiar. This Take the

Best strateg is extremel eas ad ve effective; it is eve a good wa to choosestocks that will perform well i the market Gigerezer et al. 1 999) With heuristicswe ca avoid exhaustive database searches eve whe a complete database is at ourdisposal. There are also was to search through a colossal database without much

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cost. Iteet search egies provide a existece proof Clark 2002). Cosider Google.A Google search o he word heuristic" sors through over a billio web pages i0. 1 8 secods ad he mos useful results appear i the ft few his Searc egieslook for kewords ad for webpages that have bee equel liked or accessed.If we peorm the metal equivale of a Google search o our meal fes we should

be able to call up relevat iformaio relativel quickl. Te upsho is hat ecap-sulatio is ot eeded for compuatioall tracabili.

At his poit oe migh expect Carruhers o abado the assuptio that me-tal ssems are ecapsulated stead he draws a distictio bewee two kids ofecapsulaio. Narrowscope ecapsulaio occurs whe most of te iformatio heldi he mid is such ha a ssem cat be affected b hat iformatio i he courseof processig. This is he kid of ecapsulaio that Fodor aribues o modules adi is wa Carrhers rejecs whe he appeals to heuristics I is possible at a iemof iformatio is such at a sstem could be affected b i. Bu Carrhers edorses

widescope ecapsulatio: sstems are such ha he ca be affeced b most ofhe iformaio held i te mid a he ime of processig. This seems reasoableeoug. If ever item i the mid se ipus to a give sstem siultaeousl thassem would be overwhelmed. So I accep widescope ecapsulatio." But wide-scope ecapsulatio is o reall ecapsulaio a all. Ecapsulaio implies hatoe sstem caot be accessed b aother. Widescope ecaplatio" sas that allssems are accessible te jus are accessed all a oce Carruhers ermiolo-gical move caot be used to save the hpothesis hat meal ssems are ecap-sulated. I recogizig he power of heuristic search he acitl cocedes tha theprimar argumet for ecaplatio is usuccessl.

I do ot wa o claim ha tere is no ecapsulaio i te mid. It is possiblethat some subssems are imperious to exeral iputs. wat o claim ol hatthere is a lo of crosstalk betwee meal sstems. If we tr o do meal carograph b drawig lies aroud he few subssems hat are ecapsulaed we willed up with borders tha are ot especiall elpful Ecapsulatio i is osucietl widespread o be a iteresig orgaizig priciple.

7 Conclusion: Decomposing Modularity

Throughout his discussio I have argued tha Fodors criteria for modulari do ocare out iteresig divisios i e id. Ssems hat have bee alleged to bemodular cao be characerized b e properies o Fodors lis. At best thesesstems have components that satis some of Fodors criteria. There is lile reasoto thik tha tese criteria ag togeher ad whe cosidered idividuall heapp to a scaered ad sudr assorme of subsstems. I is grossl misleadigto sa hat the mid is modular. A bes the mid has a smaterig of modular pars.

Tha does o mea ha the mid is a disorgaized mash A he outset I said

ha modulari is ot equivalet to coal decompositio. The mid ca be describedas a ework of iercoected sstems ad subssems. We ca represet e me-al divisio of labor usig owcharts whose uis correspod to cioall disi-guised compoets a carr out subrouies ad cobue i heir limited wa

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o he greaer whole. M goal has bee o criicize a specifc accou of wha hecioal uis i he mid are ke The fucioal uis eed o be fas auomaic iae shallow or ecapsulaed Some of he compoes ma be dedicaedo a sigle meal capaci bu ohers ma serve a varie of differe capaciies is possible a o compoe i he mid exhibis he prepoderace of properieso Fodors lis.

Some defeders of modulari are commied o oig more ha cioal decomposiio The rejec Fodors lis ad adop he simple view ha he mid is a machiewih compoe pars. That view is ucoroversial Massive modulri souds likea radical hesis bu whe he oio of modulari is deaured i urs io a pla-iude. Of course ceral cogiio has a varie of differe rules ad represeaiosOf course we brig differe kowledge ad skills o bear whe we reaso abou hesocial world as opposed o he world of cocree objecs. Of course i is possibe forsomeoe o lose a specifc cogiive capaci wihou losig ever oher cogiivecapaci Coovers arises ol whe fcioal compoes are presumed o have

properies o Fodors lis hik he erm modulari" should be dropped because i implies ha ma

meal ssems are modular i Fodors sese ad ha hesis lacks suppor Cogiivescieiss should coiue o egage i cioal decomposiio bu we should resishe empaio o posulae ad proliferae modules

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