MAGNITUDE ESTIMATION FOR THE METHOD OF LIMITS
A serial effect often reduces the PSE or the threshold on the ascending series and it raises them on the descending series of the method of limits. This effect has been usually explained as the error of expectation, which would occur in the process of reporting but not perception. However, as this effect appears so strongly, it seems to be reasonable to think it to be a perceptual phenomenon. I observed the successive changes of the underestimation during the ascending series and the overestimation during the descending series using the magnitude estimation in the length comparison of a pair of lines. These changes were explained as the microgenetic process of adaptation and aftereffect (Nakatani; 1995a.b).