Dai H
Department of Psychology, University of Florida, Gainesville 32611.
J Acoust Soc Am. 1994 Sep;96(3):1388-96. doi: 10.1121/1.410283.
Psychometric functions were measured for spectral-shape discrimination (profile analysis) with the signal frequency either fixed, what we call the signal-known condition, or randomly varied, what we call the signal-unknown condition. The functions were obtained using an adaptive, up-down procedure. In the signal-unknown condition, independent tracks for each signal frequency were interleaved within the same block of trials. The mean slope of the psychometric function [k in log d' = k log delta L+C, where delta L = 20 log(1 + delta p/p)] was 1.13 for the signal-known conditions and 1.19 for the signal-unknown condition. The mean signal-to-standard ratio at threshold (Pc = 79.4%) obtained in the signal-unknown condition was 3 to 4 dB higher than that obtained in the signal-known conditions. The psychometric functions of the ideal observer were derived for both the signal-known and signal-unknown conditions. A comparison of the measured and derived psychometric functions suggests that the internal noise component that is statistically independent across frequency channels contributes minimally to the total (internal and external) noise sources that are involved in the decision process.
通过自适应的上下程序测量了用于频谱形状辨别（轮廓分析）的心理测量函数，信号频率要么固定（我们称之为信号已知条件），要么随机变化（我们称之为信号未知条件）。在信号未知条件下，每个信号频率的独立轨迹在同一试验块内交错排列。心理测量函数的平均斜率[k在对数d' = k对数ΔL + C中，其中ΔL = 20对数(1 + Δp/p)]在信号已知条件下为1.13，在信号未知条件下为1.19。在信号未知条件下获得的阈值处的平均信号与标准比（Pc = 79.4%）比在信号已知条件下获得的高3至4分贝。推导了信号已知和信号未知条件下理想观察者的心理测量函数。测量的和推导的心理测量函数的比较表明，在频率通道间统计独立的内部噪声成分对决策过程中涉及的总（内部和外部）噪声源的贡献最小。
