Abstract
Cognitive penetration is the assumption that non-sensory factors influence sensory perception at the core level of sensory processing, thus generating or modifying the contents of perception. However, the experimental instances of cognitive penetration can be argued to be instances of experimental confounding that occur due to the operationalization of perception to be a magnitude estimation activity rather than as a category identification task. The magnitudinal stimuli can confound the experiments as they tend to generate perceptual fuzziness and thus lead to non-veridical overestimations as well as underestimations of those stimuli. And, these non-veridical estimations or approximations fail to be distinguishable whether they are (sensory) perceptual errors or (non-sensory) response biases per se. Moreover, the typical cognitive-penetration-like effects will not be observed if the perception is operationalized as a category identification activity, as the categorical stimuli are not fuzzy and do not lead to response biases. Thus, the purported instances of cognitive penetration can be argued to be mere instances of experimental confounding, and thus, cognitive penetration is not a valid psychological phenomenon.