Categorical Perception

From: Nethercott, C.T. (
Date: Mon May 27 1996 - 16:28:03 BST

py104 test question:What is categorical perception?

In aquiring a category we learn to label or identify positive and
negative instances from a sample of non-definable unknowns.Two types of
representation are built up in this learning by aquaintance;1) an
iconic representation that subserves each category and 2) a feature
filter which picks out invariant information allowing us to categorise
the instances correctly.This categorical representation is associated
with the category name which is held in the symbolic representational
system.It has been suggested that connectionism is the mechanism that
associates the invariants between categorisation and naming.

In the case of colour categorical perception, where differences in
wavelegnth within the range we know as yellow are percieved as being
less than equal sized differences that cross the border between
"yellow" and "green".Our ability to interperate the physical world
directly has been "warped",with some regions being compressed
(yellow-yellow differences) and some being stretched
out(yellow-green).The effect of the category boundry has therefore been
shown to be not only Quantitative but also Qualitive.Most of the
warping seems to be done by evolution,probably being an inborn property
of our sensory processing systems.When a child is born into the
"blooming buzzing confusion",it can distinguish a yellow from a
green,but without knowing that this is being done, as the connection
with the symbolic "niche" for the colour blue has not been

Categorical perception is intrinsicaly involved in differentiation
processes such as pattern recognition,the ability to do of which is the
basis of the"larger scale" cognitive thought processes.

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