I guess you can easily train gibbons with operant conditioning - and it is important to keep ambient illumination constant and make sure that the animals cannot discrimination on the basis of brightness (test for point of subjective equivalence for two colors before).

You should read the many papers published by G.H. Jacobs who, along with numerous colleagues, has performed behavioral tests on many different primate species (squirrel monkey, spider monkey, owl monkey, lemur). The methods sections of his papers give detailed descriptions of how the testing was performed. Also see his book entitled Comparative Color Vision.

I agree with Mark McCourt about using Jacobs and colleagues many references with behavioral testing….. One specific article is found here from Deegan and Jacobs (2001): https://www.researchgate.net/publication/12057194_Spectral_sensitivity_of_gibbons_implications_for_photopigments_and_color_vision

This article also discusses various stimuli used in color vision testing in primates. Waitt, C and Buchanan-Smith HM Perceptual considerations in the use of colored photographic and video stimuli to study nonhuman primate behavior. American Journal of Primatology 68: 1054–1067, 2006

Article Spectral Sensitivity of Gibbons: Implications for Photopigme...

Thank you very much for the responses. I really appreciate it.

I'd like to read those papers, unfortunately, I have requested the full-text papers to the authors, but no reply yet. If you wouldn't mind and you have them, would you spare those papers to my email [email protected], please?

Thank you so much.

Dear Abdullab Langgeng:

In 2007, Evelen Hanggi and I, used pseudoisochromatic test plates for the first time to test the color vision of horses. I copy and pasted the below from the attached .pdf article.

The findings from this study show that horses are capable of seeing color, but some colors (confusion colors) appear the same to them, which indicates a color-vision deficiency. They are most likely dichromats, perceiving colors similar to how a red-green (protanope-deuteranope) color-deficient human.

The pseudoisochromatic plate test was successful in determining equine color vision and, with appropriate adjustment, may be a suitable method for testing color vision in other animals.

Joumal of Comparative Psychology 2007, vol. 121, No. l, 65-72 Copyright 2007 by the Americm Psychological Assoc.

Color Vision in Horses( Equus  Caballus):Deficiencies Identified Using a Pseudoisochromatic Plate Test

Evelyn B. Hanggi and Jerry F. Ingersoll Equine Research Foundation

Terrace L. Waggoner Eye Clinic/Naval Hospital

I designed the PIP test plates used in the study.  I have since design "military grade computerized color vision test plates" http://www.konanmedical.com/colordx

I hope you find this helpful and good luck with your study,

Terrace L. Waggoner, O.D.