Thoss F
Acta Neurobiol Exp (Wars). 1986;46(5-6):303-10.
This investigation was initiated by the apparent rivalry between Fechner-law and Stevens-power function. We used the pupil reaction as on objective measure for the excitation of the visual system within both the threshold and the suprathreshold region. The course of the threshold as a function of adaptation light shows important differences at different field areas. The Weber-law is valid only in the case of large fields (30 degrees) as had been used by Weber himself. At smaller fields the threshold may be described as a power function with exponents of 0.5 at the smallest (0.5 degrees) and about 0.75 at medium sized (5 degrees) fields. In all these experiments the Fechner-hypothesis is suitable automatically because of the constant increment of pupil constriction at the threshold. The validity of the Fechner-hypothesis together with the approximation of the threshold course by power functions lead to Stevens-power functions for the suprathreshold region. The Fechner-law - a logarithmic function - is valid at large fields only. This consideration has been confirmed by our measurements in the suprathreshold sphere.
这项研究是由费希纳定律和史蒂文斯幂函数之间明显的竞争关系引发的。我们将瞳孔反应作为一种客观测量方法，用于在阈值和阈上区域内激发视觉系统。阈值随适应光变化的过程在不同视野区域显示出重要差异。正如韦伯本人所使用的那样，韦伯定律仅在大视野（30度）的情况下有效。在较小视野中，阈值可以描述为幂函数，在最小视野（0.5度）时指数为0.5，在中等大小视野（5度）时约为0.75。在所有这些实验中，由于在阈值处瞳孔收缩的持续增加，费希纳假设自动适用。费希纳假设的有效性以及幂函数对阈值过程的近似导致了阈上区域的史蒂文斯幂函数。费希纳定律——一个对数函数——仅在大视野时有效。我们在阈上范围的测量证实了这一观点。
