Mind, Body, World- Foundations of Cognitive Science, 2013a

Spontaneously and by our own power, we vary some of the conditions under which
the object has been perceived. We know that the changes thus produced in the
way that objects look depend solely on the movements we have executed. Thus we
obtain a different series of apperceptions of the same object, by which we can be
convinced with experimental certainty that they are simply apperceptions and that
it is the common cause of them all. (Helmholtz & Southall, 1962b, p. 31)
Helmholtz argued that the only difference between visual inference and logical reasoning
was that the former was unconscious while the latter was not, describing
“the psychic acts of ordinary perception as unconscious conclusions” (Helmholtz
& Southall, 1962b, p. 4). Consciousness aside, seeing and reasoning were processes
of the same kind: “There can be no doubt as to the similarity between the results of
such unconscious conclusions and those of conscious conclusions” (p. 4).
A century after Helmholtz, researchers were well aware of the problem of underdetermination
with respect to vision. Their view of this problem was that it was based
in the fact that certain information is missing from the proximal stimulus, and that
additional processing is required to supply the missing information. With the rise of
cognitivism in the 1950s, researchers proposed a top-down, or theory-driven, account
of perception in which general knowledge of the world was used to disambiguate the
proximal stimulus (Bruner, 1957, 1992; Bruner, Postman, & Rodrigues, 1951; Gregory,
1970, 1978; Rock, 1983). This approach directly descended from Helmholtz’s discussion
of unconscious conclusions because it equated visual perception with cognition.
One of the principal characteristics of perceiving [categorization] is a characteristic
of cognition generally. There is no reason to assume that the laws governing inferences
of this kind are discontinuous as one moves from perceptual to more conceptual
activities. (Bruner, 1957, p. 124)
The cognitive account of perception that Jerome Bruner originated in the 1950s
came to be known as the New Look. According to the New Look, higher-order cognitive
processes could permit beliefs, expectations, and general knowledge of the
world to provide additional information for disambiguation of the underdetermining
proximal stimulus. “We not only believe what we see: to some extent we see
what we believe” (Gregory, 1970, p. 15). Hundreds of studies provided experimental
evidence that perceptual experience was determined in large part by a perceiver’s
beliefs or expectations. (For one review of this literature see Pylyshyn, 2003b.) Given
the central role of cognitivism since the inception of the New Look, it is not surprising
that this type of theory has dominated the modern literature.
The belief that perception is thoroughly contaminated by such cognitive factors as
expectations, judgments, beliefs, and so on, became the received wisdom in much of
psychology, with virtually all contemporary elementary texts in human information
processing and vision taking that point of view for granted. (Pylyshyn, 2003b, p. 56)
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