Influence of serial practice on Farnsworth-Munsell 100-hue scores: the learning effect

Clinical application of the Farnsworth-Munsell 100-hue test may be compromised by uncontrolled sources of psychophysical fluctuation such as a serial practice effect. Although the literature does not report a substantial practice effect for the 100-hue test, we have measured significant improvement in performance extending over at least four test repetitions for a group of twenty-six normal naive subjects. Analysis of test taking strategy identified the most likely source of improvement as cognitive in nature and not related to the availability of the peripheral color signal. An extended training procedure was devised to minimize the serial practice effect which included intensive instruction with illustrations of correct and incorrect cap sequences and practice with verbal feedback on performance using a subset of ten 100-hue caps. Administration of the pretest training was found to minimize the practice effect in an additional group of thirty initially naive subjects. Using pretest training, we were also able to record consistent 100-hue intensity-response functions over five illumination levels.