Nikolic et al. (2007)

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Revision as of 15:21, 28 April 2008

Color Opponency in Synaesthetic Experiences

Introduction

The Stroop task asks participants to say the name of the color a word is written in. Time reaction is measured. The challenging thing about this task is that generally the word written is the name of a different color than the color ink it is written in.

Example of a Stroop Task

In this experiment, thte task is attempting to study grapheme color synaesthesia, which is a neurological condition where perceptions of words or numbers are associated with perception of colors. In synaesthetes, the reaction time is decreased if the ink color of the word being read is the same color as the synaesthetic color association (congruent condition). There is a longer reaction time if the two colors are different (incongruent conditions).

There is a neurological explanation for this as discovered through the use of MRI tests. In the brain, certain neurons perceive and process visual stimuli. These neurons have color-opponent fields. For example, cells excited by red are inhibited by green, and the reverse is true. The same situation exists with cells excited by blue and inhibited by yellow.

This study attempts to identify the neural location of these color interactions. A specific Stroop test was created for this study that created incongruent conditions. One task's real color was opponent to the synaesthetic color, and the other had the real color not opposing the synaesthetic color. The hypothesis is that in the opponent incongruent conditions the two colors would involve the same color channels in the brain, and that in the non-opposing incongruent condition the colors would be perceived by different channels. It was hypothesized that it will take participants longer to name the colors that are opponent.

Experiment I

Experiment II

General Discussion