Before revision:  So far, no theoretical description has been offered to explain the trial-to-trial variability , whereas the sources of the subject-to-subject variability have been associated with individual differences in the properties of the peripheral visual system.
After revision:  So far, no theoretical description has been offered to explain the trial-to-trial variability and the correlations of color matching functions stemming from Poissonian noise in photon capture. We analyze how the statistical properties of the peripheral visual system.