Categorical colour perception is the area I specialised in during my PhD studies, which I completed under the supervision of Professor Ian Davies at the University of Surrey in UK. On one level, the question we explored was an old and famous debate: linguistic relativity. According to this hypothesis, language and thought are inextricably linked. Thought processes of a culture might be influenced, if not determined by its language.

In this context, colour perception and cognition have attracted a lot of research interest, mainly due to the seemingly high level of variation in the colour names of different languages. Is it possible that people who have different colour categories in their language "see" colours differently as well?!

My research in this area has focused on changing the way people see colours in laboratory conditions. If language could modify colour perception, training in the laboratory might be able to do so too. This approach has its roots in research on a phenomenon called perceptual learning: the observation that people improve in their ability to make finer and finer discriminations with practice. My research in colour therefore concentrates on modification of categorical colour perception through perceptual learning mechanisms.

Our perceptual learning and category learning experiments have suggested that through repeated practice, observers improve their ability to distinguish between colours. Such improvement occurs both when observers practise discrimination of a specifed range of colour differences, and when ther are required to learn novel category boundaries. Further, we observe these effects for hue as well as lightness discriminations.

I also carry out field and laboratory research on cross-cultural comparisons of colour perception and cognition. We have been uncovering evidence, which suggests that speakers of languages that encode colour space in different ways, show corresponding differences in colour discrimination. In other words, where there is a linguistic category boundary, people are more sensitive to colour differences across that boundary, than where no language boundary occurs.

However, in all of these findings and others there is an underlying and very important question: is this really vision? The evidence regarding the locus of the effects we have been reporting is not yet conclusive. It is possible that vision is not affected by laboratory training or indeed language. Instead, some high level mechanisms may be responsible for the effects we have been observing. It is therefore crucial to determine at which point in the visual processing stream such effects occur, in order to contribute to the cognitive penetrability argument. In this capacity, in the recent years I, along with colleagues in UK, have focused my attention on psychophysical methods (such as discrimination threshold estimates) to try and pinpoint the locus of learned categorical perception effects. We also apply the same methods in cross-cultural research, although this is more problematic.

To see a list of my publications, and read some more on the subject please follow the link to publications on the left.