Eye colour: an unconsidered variable in cognitive research?

Evidence analysed based on reaction time has contributed to the development of cognitive models of human information processing. Essential to the consideration of possible variables to be controlled when designing experimental work on cognitively related issues are variables such as the subjects' age, sex, or education. Barely a handful of studies have ever taken eye colour seriously as a variable to be controlled when exploring cognitively related issues. Very few researchers have considered the possibility that a person's eye colour might influence reaction time. The question is whether eye colour should be taken seriously when designing experimental work in cognitive psychology. In this study we found significant differences in choice reaction time using the McCarthy and Donchin (1981) paradigm, the dark-eyed subjects being faster tha the light-eyed. Implications of the findings are discussed.