抄録
Pigeons were trained to discriminate between two wavelengths (420-470, 470-520, 520-570, 570-650 and 470-650nm) with a yes/no procedure. The post-discrimination gradients were analysed with the signal detection methods, and a psychometric hue discrimination function ranging from 420 to 650 nm was obtained. A set of discrimination indices (d') was linearly related to wave-number differences, and lines were fitted to the data points. The slope values showed that the visible spectrum was grouped into four sets of wave-lengths where there is a slow change in hue and three sets of wavelengths where there is a rapid change in hue.