Ward L M, Armstrong J, Golestani N
Department of Psychology, University of British Columbia, Vancouver, Canada.
Percept Psychophys. 1996 Jul;58(5):793-801. doi: 10.3758/bf03213110.
Several successful theories of psychophysical judgment imply that exponents of power functions in scaling tasks should covary with measures of intensity resolution such as d' in the same tasks, whereas the prevailing metatheory of ideal psychophysical scaling asserts the independence of the two. In a direct test of this relationship, three prominent psychophysical scaling paradigms were studied: category judgment without an identification function, absolute magnitude estimation, and cross-modality matching with light intensity as the response continuum. Separate groups of subjects for each scaling paradigm made repeated judgments of the loudnesses of the pure tones that constituted each of two stimulus ensembles. The narrow- and wide-range ensembles shared six identical stimulus intensities in the middle of each set. Intensity resolution, as measured by d'-like distances, of these physically identical stimuli was significantly worse for the wide-range set for all three methods. Exponents of power functions fitted to geometric mean responses, and in magnitude estimation and cross-modality matching the geometric mean responses themselves, were also significantly smaller in the wide-range condition. The variation of power function exponents, and of psychophysical scale values, for stimulus intensities that were identical in the two stimulus sets with the intensities of other members of the ensembles is inconsistent with the metatheory on which modern psychophysical scaling practice is based, although it is consistent with other useful approaches to measurement of psychological magnitudes.
几种成功的心理物理学判断理论表明，在标度任务中幂函数的指数应该与同一任务中的强度分辨率测量值（如d'）共同变化，而理想心理物理学标度的主流元理论则主张两者相互独立。在对这种关系的直接测试中，研究了三种著名的心理物理学标度范式：没有识别功能的类别判断、绝对大小估计以及以光强度作为响应连续体的跨通道匹配。针对每种标度范式，不同组的受试者对构成两个刺激集的纯音的响度进行了重复判断。窄范围和宽范围的刺激集在每组中间共享六个相同的刺激强度。对于这三种方法，通过类似d'的距离测量的这些物理上相同的刺激在宽范围刺激集中的强度分辨率明显更差。在宽范围条件下，拟合几何平均反应的幂函数的指数，以及在大小估计和跨通道匹配中几何平均反应本身，也明显更小。对于两个刺激集中相同的刺激强度以及与刺激集其他成员强度的幂函数指数和心理物理学标度值的变化，与现代心理物理学标度实践所基于的元理论不一致，尽管它与其他测量心理量值的有用方法一致。
