Construction of equal-hue discriminability scales for the pigeon.

The paper gives ready-made tables that turn pigeon color vision into equal steps.

You pick any two colors and the table tells you how far apart they look to a pigeon.

No birds were trained; the work is pure measurement so later studies can use fair color intervals.

The tables let you build color pairs that are equally easy—or hard—for pigeons to tell apart.

Equal physical steps do not mean equal perceptual steps; the scales fix that.

Meltzer (1983) taught pigeons a conditional task with blurry color cues. Using the 1978 scales would have kept the color difficulty the same while the blur changed.

Ohta (1987) showed that color cues can become mini-rewards if they predict food. The 1978 tables help you pick colors matched for salience so the reward effect is not just because one color pops more.

Wolchik et al. (1982) varied how often correct pecks were rewarded. Their color differences were arbitrary; plugging in the 1978 scales would hold discriminability steady while only the pay-off changes.

If you run any pigeon lab task with color—discrimination, errorless teaching, contrast, or observing—these scales give you a ruler. Swap in table values instead of guessing color distances and your stimulus control becomes cleaner, comparisons across studies fairer, and replications easier.