Is perception informationally encapsulated? The issue of the theory‐ladenness of perception

Abstract

Fodor has argued that observation is theory neutral, since the perceptual systems are modular, that is, they are domain-specific, encapsulated, mandatory, fast, hard-wired in the organism, and have a fixed neural architecture. Churchland attacks the theoretical neutrality of observation on the grounds that (a) the abundant top-down pathways in the brain suggest the cognitive penetration of perception and (b) perceptual learning can change in the wiring of the perceptual systems. In this paper I introduce a distinction between sensation, perception, and observation and I argue that although Churchland is right that observation involves top-down processes, there is also a substantial amount of information in perception which is theory-neutral. I argue that perceptual learning does not threaten the cognitive impenetrability of perception, and that the neuropsychological research does not provide evidence in favor of the top-down character of perception. Finally, I discuss the possibility of an off-line cognitive penetrability of perception.

Cognitive Penetration, Perceptual Learning and Neural Plasticity

“…The visual processing becomes cognitive when the visual output is recognized and categorized. Cognitive processes depend on the subject's cognitive background, and are, by definition, cognitively penetrable (see Pylyshyn , 134–135; Raftopoulos , 427; , 77, 80).…”

“…All subsequent higher visual processes requiring memory belong to what is known as “cognition” (Pylyshyn , 344) or “observation” (Raftopoulos , 51). Early vision is impervious to cognitive influences – that is, encapsulated from cognition, or cognitively impenetrable (Fodor and Pylyshyn ; Fodor 1983; 2000; Pylyshyn 1984; 1999; 2003; Raftopoulos 2001a; 2001b; 2005b; 2009).…”

“…Shifts of attentional focus are not considered as cases of cognitive penetration (Fodor , 190–192; Pylyshyn , 344; Raftopoulos , 81; , 277–290; Siegel , 205–206; Macpherson , 29; Stokes , 650, 655) . According to Pylyshyn (, 353) and Raftopoulos (, 438–439), the allocation of attention is prior to the operation of early vision. That is, the focus of attention is a pre‐perceptual stage which makes the visual stimuli accessible for further processing.…”

“…Attention functions then as a gate‐keeper which picks out the information from the spotlight that is pertinent for the subject's current goals and makes it accessible to the organism. This is an intrinsic and more sophisticated dimension of attention called the “gating” of attention (Karni and Sagi , 4970; , 8–9; Pylyshyn , 345, 359–361; Raftopoulos , 444; , 303–304; Gilbert and Sigman , 688–689)…”

“…Nevertheless, according to Pylyshyn (1984; 1999; 2003) and Raftopoulos (2001a;b; 2005b; 2009), the gating of attention does not threaten cognitive impenetrability of perception in perceptual learning . Either the gating is produced by stimulus‐driven attention (i.e., selection is independent of top‐down influences), or cognitively driven attention influences the visual system at a post‐perceptual stage (Pylyshyn , 359–360; Raftopoulos , 443–444; , 76; , 303–304). However, Raftopoulos () recognizes that cognitively guided attention facilitates the gating of visual properties by pervading early vision, but claims that this influence does not undermine cognitive impenetrability of perception.…”