Cognitive Penetrability and the Epistemic Role of Perception by Athanassios Raftopoulos

Author:Athanassios Raftopoulos
Language: eng
Format: epub, pdf
ISBN: 9783030104450
Publisher: Springer International Publishing

He then adds thatIn fact, even if a paradigmatically perceptual process is itself top-down, this does not entail that it is not stimulus-controlled. Feedback mechanisms in early visual areas (e.g. from V2 to V1) function so as to be causally controlled by proximal stimuli.

So, for Phillips, the existence of recurrent, top-down processes in a visual stage does not entail that this stage is not paradigmatically, purely (recall that Phillips discusses narrowly defined, pure, perception), perceptual. In agreement with the abovementioned commentary on the empirical evidence, Phillips thinks of these top-down influences as being controlled by the stimulus, and, thus, as stimulus-driven, which means that at this stage there are no cognitive influences.

One could argue that even though the evidence adduced thus far shows that the recurrent signals from MT/V5 to V1 carry no cognitive information, it is still possible that cognitive centers send directly cognitive information to V1/V2 bypassing MT/V5, or, V4 or LOC, because as I will argue in the next section no cognitive influences can be found in the recurrent processes involving those areas as well. One such possibility is FEF that is in the dorsal pre-frontal cortex and is known to mediate both shifts of overt attention and shifts of covert attention that precede saccades and, therefore, its function is affected by cognitive factors that drive attention. We shall see, however, that to the extent that FEF is involved in early visual processing and not in the planning of attentional shifts, there are no cognitive influences involved in this recurrent processing. In general, as the discussion on the role of N1 shows, all cognitive influences whatever their source might be are delayed in time and do not affect early vision.

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