The normal variations of the duration of load adaptation were studied in the well defined and photopic experimental conditions offered by Goldman's static perimeter and using as criterion the time interval between the beginning and the first complete collapse of the perception of the object. The spread of the durations measured in constant experimental conditions is logarithmic-normal, the standard deviation always being about 0,2 decimal logarithmic unit as well at the individual at the inter-individual level. Furthermore, the mean duration increases with higher object luminance, this relationship being of an experimental type and not compatible with a photochemical theory of local adaption; the angular surface of the object also in influence the results, and the same holds for eccentricity, as the duration certainly increases when the object is moved from 2- to 2; on the other hand, the coupling of a colour sensation to the brightness sensation, achieved by a modification of the spectral repartition of the object, does not exert a noticeable effect.
Abstract