Note on the fusion frequency for stimuli of alternating duration

The case of alternating stimulus patterns of moderately high intensity is considered in terms of the model previously discussed (Landahl, 1957,Bull. Math. Biophysics,19, 157–62). If both of the alternating patterns have the same light-dark ratio, then the relation between the period of the longer and the period of the shorter pattern at the critical flicker frequency is independent of the light-dark ratio and is given by a dimensionless expression which is roughly in agreement with data in which the light-dark ratio is one (C. R. Brown and D. M. Forsyth, 1959,Science,129, 390–91). This research was supported in whole or in part by the U. S. Air Force under Contract AF 49(638)-414 monitored by the Air Force Office of Scientific Research.