A Deflationary Approach to the Cognitive Penetration Debate

Dan Burnston—Assistant Professor, Philosophy Department, Tulane University, Member Faculty in the Tulane Brain Institute

I con­strue the debate about cog­nit­ive pen­et­ra­tion (CP) in the fol­low­ing way: are there caus­al rela­tions between cog­ni­tion and per­cep­tion, such that the pro­cessing of the later is sys­tem­at­ic­ally sens­it­ive to the con­tent of the former? Framing the debate in this way imparts some prag­mat­ic com­mit­ments. We need to make clear what dis­tin­guishes per­cep­tion from cog­ni­tion, and what resources each brings to the table. And we need to cla­ri­fy what kind of caus­al rela­tion­ship exists, and wheth­er it is strong enough to be con­sidered “sys­tem­at­ic.”

I think that cur­rent debates about cog­nit­ive pen­et­ra­tion have failed to be clear enough on these vital prag­mat­ic con­sid­er­a­tions, and have become muddled as a res­ult. My view is that once we under­stand per­cep­tion and cog­ni­tion aright, we should recog­nize as an empir­ic­al fact that there are caus­al rela­tion­ships between them—however, these rela­tions are gen­er­al, dif­fuse, and prob­ab­il­ist­ic, rather than spe­cif­ic, tar­geted, and determ­in­ate. Many sup­port­ers of CP cer­tainly seem to have the lat­ter kind of rela­tion­ship in mind, and it is not clear that the former kind sup­ports the con­sequences for epi­stem­o­logy and cog­nit­ive archi­tec­ture that these sup­port­ers sup­pose. My primary goal, then, rather than deny­ing cog­nit­ive pen­et­ra­tion per se, is to de-fuse it (Burnston, 2016, 2017a, in prep).

The view of per­cep­tion, I believe, that informs most debates about CP, is that per­cep­tion con­sists in a set of strictly bottom-up, mutu­ally encap­su­lated fea­ture detect­ors, per­haps along with some basic mech­an­isms for bind­ing these fea­tures into dis­tinct “proto” objects (Clark, 2004). Anything cat­egor­ic­al, any­thing that involves inter-featural (to say noth­ing of inter­mod­al) asso­ci­ation, any­thing that involves top-down influ­ence, or assump­tions about the nature of the world, and any­thing that is learned or involves memory, must strictly be due to cog­ni­tion.

To those of this the­or­et­ic­al per­sua­sion, evid­ence for effects of some sub­set of these types in per­cep­tion is prima facie evid­ence for CP.[1] Arguments in favor of CP move from the sup­posed pres­ence of these effects, along with argu­ments that they are not due to either pre-perceptual atten­tion­al shifts or post-perceptual judg­ments, to the con­clu­sion that CP occurs.

On reflec­tion, how­ever, this is a some­what odd, or at least non-obvious move. We start out from a pre­sup­pos­i­tion that per­cep­tion can­not involve X. Then we observe evid­ence that per­cep­tion does in fact involve X. In response, instead of modi­fy­ing our view of per­cep­tion, we insist that only some oth­er fac­ulty, like cog­ni­tion, must inter­vene and do for per­cep­tion that for which it, on its own, lacks. My argu­ments in this debate are meant to under­mine this kind of intu­ition by show­ing that, giv­en a bet­ter under­stand­ing of per­cep­tion, not only is pos­it­ing CP not required, it is also (in its stronger forms any­way) simply unlikely.

Consider the fol­low­ing example, the Cornsweet illu­sion (also called the Craik‑O’Brien-Cornsweet illu­sion).

Figure 1. The Cornsweet illu­sion.

In this kind of stim­u­lus, sub­jects almost uni­ver­sally per­ceive the patch on the left as dark­er than the patch on the right, des­pite the fact that they have the exact same lumin­ance, aside from the dark-to-light gradi­ent on the left of the cen­ter line (the “Cornsweet edge”) and the light-to-dark gradi­ent on the right. The stand­ard view of the illu­sion in per­cep­tu­al sci­ence is that per­cep­tion assumes that the object is exten­ded towards the per­ceiv­er in depth, with light com­ing from the left, such that the pan­el on the left would be more brightly illu­min­ated, and the patch on the right more dimly illu­min­ated.  Thus, in order for the left pan­el to pro­duce the same lumin­ance value at the ret­ina as the right pan­el, it must in fact be dark­er, and the visu­al sys­tem rep­res­ents it so: such effects are the res­ult of “an extraordin­ar­ily power­ful strategy of vis­ion” (Purves, Shimpi, & Lotto, 1999, p. 8549).[2]

Why con­strue the strategy as visu­al? There are a num­ber of related con­sid­er­a­tions. First, the phe­nomen­on involves fine-grained asso­ci­ations between par­tic­u­lar fea­tures (lumin­ance, dis­con­tinu­ity, and con­trast, in par­tic­u­lar con­fig­ur­a­tions) that vary sys­tem­at­ic­ally and con­tinu­ously with the amount of evid­ence for the inter­pret­a­tion. If one increases the depth-interpretation by fore­short­en­ing or “bow­ing” the fig­ure, the effect is enhanced, and with fur­ther mod­u­la­tion one can get quite pro­nounced effects. It is unclear at best when we would have come by such fine-grained beliefs about these stim­uli. Moreover, the effects are man­dat­ory, and oper­ate insens­it­ively to changes in our occur­rent beliefs. Fodor is (still) right, in my view, that this kind of man­d­it­or­i­ness sup­ports a per­cep­tu­al read­ing.

According to Jonathan Cohen and me (Burnston & Cohen, 2012, 2015), cur­rent per­cep­tu­al sci­ence reveals effects like this to be the norm, at all levels of per­cep­tion. If this “integ­rat­ive” view of per­cep­tion is true, then embody­ing assump­tions in com­plex asso­ci­ations is no evid­ence for CP—in fact it is part-and-parcel of what per­cep­tion does.

What about cat­egor­ic­al per­cep­tion? Consider the fol­low­ing example from Gureckis and Goldstone (2008), of what is com­monly referred to as a morph­space.

Figure 2. Categories for facial per­cep­tion.

According to cur­rent views (Gauthier & Tarr, 2016; Goldstone & Hendrickson, 2010), cat­egor­ic­al per­cep­tion involves higher-order asso­ci­ations between cor­rel­ated low-level fea­tures. So, recog­niz­ing a par­tic­u­lar cat­egory of faces (for instance, an individual’s face, a gender, or a race) involves being able to notice cor­rel­a­tions between a num­ber of low-level facial fea­tures such as light­ness, nose or eye shape, etc., as well as their spa­tial con­fig­ur­a­tions (e.g., the dis­tance between the eyes or between the nose and the upper lip). A wide range of per­cep­tu­al cat­egor­ies have been shown to oper­ate sim­il­arly.

Interestingly, form­ing a cat­egory can morph these spaces, to group exem­plars togeth­er along the rel­ev­ant dimen­sions. In Gureckis and Goldstone’s example, once sub­jects learn to dis­crim­in­ate A from B faces (defined by the arbit­rary cen­ter line), nov­el examples of A faces will be judged to be more alike each oth­er along dia­gnost­ic dimen­sion A than they were pri­or to learn­ing. Despite these effects being cat­egor­ic­al, I sug­gest that they are strongly ana­log­ous to the cases above—they involve fea­t­ur­al asso­ci­ations that are fine-grained (a dimen­sion is “morph­ed” a par­tic­u­lar amount dur­ing the course of learn­ing) and man­dat­ory (it is hard not to see, e.g., your brother’s face as your broth­er) in a sim­il­ar way to those above. Moreover, sub­jects are often simply bad at describ­ing their per­cep­tu­al cat­egor­ies. In stud­ies such as Gureckis and Goldstone’s, sub­jects have trouble say­ing much about the dimen­sion­al asso­ci­ations that inform their per­cepts. As such, and giv­en the resources of the integ­rat­ive view, a way is opened to see­ing these cat­egor­ic­al effects as occur­ring with­in per­cep­tion.[3]

If being asso­ci­at­ive, assumption-involving, or cat­egor­ic­al doesn’t dis­tin­guish a per­cep­tu­al from a cog­nit­ive rep­res­ent­a­tion, what does? While there are issues cash­ing out the dis­tinc­tion in detail, I sug­gest that the best way to mark the perception/cognition dis­tinc­tion is in terms of rep­res­ent­a­tion­al form. Cognitive rep­res­ent­a­tions are dis­crete and language-like, while per­cep­tu­al rep­res­ent­a­tions rep­res­ent struc­tur­al dimen­sions of their referents—these might include shape dimen­sions (tilt, slant, ori­ent­a­tion, curvature, etc.), the dimen­sions that define the phe­nom­en­al col­or space, or higher-order dimen­sions such as the ones in the face case above. The form dis­tinc­tion cap­tures the kinds of con­sid­er­a­tions I’ve advanced here, as well as being com­pat­ible with wide range of related ways of draw­ing the dis­tinc­tion in philo­sophy and cog­nit­ive sci­ence.

With these dis­tinc­tions in place, we can talk about the kinds of cases that pro­ponents of CP take as evid­ence. On Macpherson’s example, Delk and Fillenbaum’s stud­ies pur­port­ing to show that “heart” shapes are per­ceived as a more sat­ur­ated red than non-heart shapes. Let’s put aside for a moment the pre­val­ent meth­od­o­lo­gic­al cri­tiques of these kinds of stud­ies (Firestone & Scholl, 2016). Even so, there is no reas­on to read the effect as one of cog­nit­ive pen­et­ra­tion. Simply the belief “hearts are red,” accord­ing to the form dis­tinc­tion, does not rep­res­ent the struc­tur­al prop­er­ties of the col­or space, and thus has no resources to inform per­cep­tion to modi­fy itself any par­tic­u­lar way. Of course, one might pos­it a more spe­cif­ic belief—say, that this par­tic­u­lar heart is a par­tic­u­lar shade of red—but this belief would have to be based on per­cep­tu­al evid­ence about the stim­u­lus. If per­cep­tion couldn’t rep­res­ent this stim­u­lus as this shade on its own, we wouldn’t come by the belief. Moreover, on the integ­rat­ive view this is the kind of thing per­cep­tion does any­way. Hence, there is no reas­on to see the per­cept as being the res­ult of cog­nit­ive inter­ven­tion.

In cat­egor­ic­al con­texts, one strong motiv­a­tion for cog­nit­ive pen­et­ra­tion is the idea that per­cep­tu­al cat­egor­ies are learned, and often this learn­ing is informed by pri­or beliefs and instruc­tions (Churchland, 1988; Siegel, 2013; Stokes, 2014). There are prob­lems with these views, how­ever, both empir­ic­al and con­cep­tu­al. The empir­ic­al prob­lem is that learn­ing can occur without any cog­nit­ive influ­ence what­so­ever. Perceivers can become attuned to dia­gnost­ic dimen­sions for entirely nov­el cat­egor­ies simply by view­ing exem­plars (Folstein, Gauthier, & Palmeri, 2010). Here, sub­jects have no pri­or beliefs or instruc­tions for how to per­ceive the stim­u­lus, but per­cep­tu­al learn­ing occurs any­way. In many cases, how­ever, even when beliefs are employed in learn­ing a cat­egory, it’s obvi­ous that the belief does not encode any con­tent that is use­ful for inform­ing the spe­cif­ic per­cept. In Goldstone and Gureckis’ case above, sub­jects were shown exem­plar faces and told “this is an A” or “this is a B”. But this index­ic­al belief does not describe any­thing about the cat­egory they actu­ally learn.

One might expect that more detailed instruc­tions or pri­or beliefs can inform more detailed categories—for instance Siegel’s sug­ges­tion that noviti­ate arbor­ists be told to look at the shape of leaves in order to dis­tin­guish (say) pines from birches. However, this runs dir­ectly into the con­cep­tu­al prob­lem. Suppose that pine leaves are pointy while birch leaves are broad. Learners already know what pointy and broad things look like. If these beliefs are all that’s required, then sub­jects don’t need to learn any­thing per­cep­tu­ally in order to make the dis­crim­in­a­tion. However, if the beliefs are not suf­fi­cient to make the discrimination—either because it is a very fine-grained dis­crim­in­a­tion of shape, or because pine versus birch per­cep­tions in fact require the kind of higher-order dimen­sion­al struc­ture dis­cussed above—then their con­tent does not describe what per­cep­tion learns when sub­jects do learn to make the dis­tinc­tion per­cep­tu­ally.[4] In either case, there is a gap between the con­tent of the belief and the con­tent of the learned perception—a gap that is sup­por­ted by stud­ies of per­cep­tu­al learn­ing and expert­ise (for fur­ther dis­cus­sion, see Burnston, 2017a, in prep). So, while beliefs might be import­ant caus­al pre­curs­ors to per­cep­tu­al learn­ing, they do not pen­et­rate the learn­ing pro­cess.

So, the situ­ation is this: we have seen that, on the integ­rat­ive view and the form dis­tinc­tion, cog­ni­tion does not have the resources to determ­ine the kind of per­cep­tu­al effects that are of interest in debates about CP. In both syn­chron­ic and dia­chron­ic cases, per­cep­tion can do much of the heavy lift­ing itself, thus ren­der­ing CP unne­ces­sary to explain the effects. A final advant­age of this view­point, espe­cially the form dis­tinc­tion, is that it brings par­tic­u­lar forms of evid­ence to bear on the debate—particularly evid­ence about what hap­pens when pro­cessing of lexical/amodal sym­bols does in fact inter­act with pro­cessing of mod­al ones. The details are too much to go through here, but I argue that the key to under­stand­ing the rela­tion­ship between per­cep­tion and cog­ni­tion is to give up the notion that there are ever dir­ect rela­tion­ships between the token­ing of a par­tic­u­lar cog­nit­ive con­tent and a spe­cif­ic per­cep­tu­al out­come (Burnston, 2016, 2017b). Instead, I sug­gest that token­ing a cog­nit­ive concept biases per­cep­tion towards a wide range of pos­sible out­comes. Here, rather than determ­in­ate cas­u­al rela­tion­ships, we should expect highly prob­ab­il­ist­ic, highly gen­er­al, and highly flex­ible inter­ac­tions, where cog­ni­tion does not force per­cep­tion to act a cer­tain way, but can shift the baseline prob­ab­il­ity that we’ll per­ceive some­thing con­sist­ent with the cog­nit­ive con­tent. This brings prim­ing, atten­tion­al, and mod­u­lat­ory effects under a single rub­ric, but not one on which cog­ni­tion tinkers with the intern­al work­ings of spe­cif­ic per­cep­tu­al pro­cesses to determ­ine how they work in a giv­en instance. I thus call it the “extern­al effect” view of the cognition-perception inter­face.

Now it is open to the defend­er of cog­nit­ive pen­et­ra­tion to define this dif­fuse inter­ac­tion as an instance of penetration—penetration is a the­or­et­ic­al term one may define as one likes. I think, how­ever, that this notion is not what most cog­nit­ive pen­et­ra­tion the­or­ists have in mind, and it does not obvi­ously carry any of the sup­posed con­sequences for mod­u­lar­ity, the­or­et­ic­al neut­ral­ity, or the epi­stem­ic role of per­cep­tion that pro­ponents of CP assume (Burnston, 2017a; cf. Lyons, 2011). The kind of view I’ve offered cap­tures, in the best avail­able empir­ic­al and prag­mat­ic way, the range of phe­nom­ena at issue, and does so very dif­fer­ently than stand­ard dis­cus­sions of pen­et­ra­tion.



Burnston, D. C. (2016). Cognitive pen­et­ra­tion and the cognition–perception inter­face. Synthese, 1–24. DOI: doi:10.1007/s11229-016‑1116‑y

Burnston, D. C. (2017a). Is aes­thet­ic exper­i­ence evid­ence for cog­nit­ive pen­et­ra­tion? New Ideas in Psychology. DOI: https://doi.org/10.1016/j.newideapsych.2017.03.012

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[1] Different the­or­ists stress dif­fer­ent prop­er­ties. Macpherson (2012) stresses effects being cat­egor­ic­al and asso­ci­ation­al, Nanay (2014) and Churchland (1988) their being top-down. Raftopoulos (2009) cites the role of memory in cat­egor­ic­al effects and Stokes (2014) and Siegel (2013) the import­ance of learn­ing in such con­texts.

[2] This kind of read­ing of intra-perceptual pro­cessing is extremely com­mon across a range of the­or­ists and per­spect­ives in per­cep­tu­al psy­cho­logy (e.g., Pylyshyn, 1999; Rock, 1983; Yuille & Kersten, 2006).

[3] This view also rejects the attempt to make these effects cog­nit­ive by defin­ing them as tacit beliefs. The prob­lem with tacit beliefs is that they simply dic­tate that any­thing cor­res­pond­ing to a cat­egory or infer­ence must be cog­nit­ive, which is exactly what’s under dis­cus­sion here. The move thus doesn’t add any­thing to the debate.

[4] This requires assum­ing a “spe­cificity” con­di­tion on the con­tent of a pur­por­ted pen­et­rat­ing belief—namely that a can­did­ate pen­et­rat­or must have the con­tent that per­cep­tion learns to rep­res­ent. I argue in more detail else­where that giv­ing this con­di­tion up trivi­al­izes the pen­et­ra­tion thes­is (Burnston, in prep).