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Description / Abstract:
SUMMARY
The work for the report was initiated by CIE Division 1: Vision
and Colour and was carried out in the Reportership R 1-11:
"Cognitive Aspects of Colour", under the following terms of
reference:
To report on the cognitive aspects of colour in terms of
behavioural, neuropsychological, and neuro-physiological data.
Cognitive aspects of colour are not given in the CIE definitions of
psychophysical colour and perceived colour.
The final report from R 1-11 was published with the title
"Cognitive Color" in Color Research and Application,
29(1), pp. 7-19. 2004. In this article, the
concept of cognitive colour was discussed in relation to colour
categorization, colour coding, colour naming, the Stroop effect,
spatial organization of coloured visual objects, attention, visual
search and colour memory.
The results show that there are aspects of colour that the CIE
definitions of psychophysical and perceived colour do not cover,
although it gives notes to some of them. These phenomena could be
referred to as "cognitive colour" and they point to the need for a
new formal definition of colour in the CIE terminology. It is
recommended that the term "cognitive colour" be added to ILV.
Cognitive colour is very important in certain specific tasks.
Some of these tasks are listed in Derefeldt et al.'s paper
(Cognitive Color. Color Research and Application,
29(1), pp. 7-19, 2004). A common property of these
tasks is the importance of the economy of cognition of the human
brain. It means that perceived colours are represented and stored
in a compressed form i.e. as "cognitive colours". This accelerates
complex tasks like visual attention, visual search, figural
organization, figural segregation, etc. This economy has probably
been of great survival value. For these tasks, colour appearance
models alone, including the calculations recommended for assessing
colour appearance and colour differences, may be limited for
predicting how an observer will behave in these complex tasks. We
must define cognitive colours by the boundaries of a continuous
perceived colour set, or by a "representative item" of this set,
and assign a name to the cognitive colour. If the perceived colour
changes, e.g. due to illumination change and colour inconstancy,
then the cognitive colour may also change.
We must be able to describe whether the cognitive colour changes
or not. We can provide some guidance on how to select colours that
are "cognitively consistent". These "cognitively consistent"
perceived colours may be the "representative items" mentioned
above, e.g. the focal colours or the prototypical colours of
familiar objects (skin, sky, grass, fruits, vegetables, natural
objects like sand, soil, water). At the boundaries of the set of
perceived colours, observers tend to disagree, see Boynton, R.M.,
Olson, C.X. Locating basic colours in the OSA space. Color Res.
Appl., 12, pp. 94-105, 1987.
It is also recommended that the work carried out in TC 1-42
"Colour Appearance in Peripheral Vision", in TC 1-61: "Categorical
Colour Identification" and TC 1-65: "Visual Appearance
Measurement", all of them representing interesting aspects of
cognitive colour, should incorporate the findings and conclusions
from this report. The results presented in "Cognitive Colour"
should also be of significance for the work carried out on
electronic imaging within Division 8: Image Technology.
Finally, it is recommended that work on the "emotional aspects
of colour" be initiated. Emotions and feelings are related to both
the cognitive and perceptual aspects of colour but the emotional
aspects of colour are not addressed within any TC within CIE
Division 1. Emotions and feelings are important aspects of how
colour and light affect human expectations, motivations, and
performance.