Because of the increasing use of colour as a primary cue developing concept and as a contextual cue, this study was conducted to modify presentations of the 100-Hue Test for colour discrimination in order to make it a useable instrument for screening the elementary school child who might have difficulties with colour discrimination though he is not a colour defective, which could handicap his school performance. The subjects were 124 boys, aged 12 years. They were divided into four equivalent groups in relation to I.Q. The Ss were Vancouver, B.C. elementary public school children. The Dvorine Pseudo-Isochromatic plates were shown to each subject as a means of establishing rapport and quickly identifying colour defectives so that they could be excluded from the sample - 4 defectives were found who had congenital anomalies. This percentage of 4.9 was lower than the commonly reported 8.1% for the male population. Group 1 were read the standard adult instructions from the Farnsworth-Munsell 100-Hue manual, before being asked to complete the test. Group 2 were read the standard adult instructions from the Farnsworth manual for the Panel D-15 (Dichotomous Test for Colour Blindness), before completing this test plus the adult instructions from the 100-Hue manual, before completing the latter test. Group 3 were read a standardized set of modified instructions which were created for this study. Group 4 were read the same set of modified instructions with the addition of the use of the Panel D-15 as part of the instructions. Statistical analysis of the mean error scores for the 4 groups revealed, as hypothesized, statistically different means between the groups using the modified and those using the standard instructions. Group 3, using modified instructions without the inclusion of the Panel D-15 performed best, functioning as well with these instructions as do adult subjects. The results indicate that 12 year olds can function significantly better on the 100-Hue test with modified instruction than other studies with other populations of children, using other types of presentations have indicated. / Education, Faculty of / Educational and Counselling Psychology, and Special Education (ECPS), Department of / Graduate