Intensity Perception. I. Preliminary Theory of Intensity Resolution

TLDR

The authors aim to develop a quantitative theory of intensity resolution applicable to diverse discrimination, identification, and scaling experiments. The theory combines a Thurstonian decision model that separates sensitivity from response bias with an internal-noise model that distinguishes sensory from memory limitations, assumes two memory modes (sensory‑trace and context‑coding), and predicts resolution in one‑interval paradigms from the total intensity range and in two‑interval paradigms from both the total range and the inter‑interval duration. The theory offers a new interpretation of the 7 ± 2 phenomenon.

Abstract

An attempt is made to develop a quantitative theory of intensity resolution that is applicable to a wide variety of experiments on discrimination, identification, and scaling. The theory is composed of a Thurstonian decision model, which separates sensitivity from response bias, and an internal-noise model, which separates sensory limitations from memory limitations. It is assumed that the subject has two memory operating modes, a sensory-trace mode and a context-coding mode, and that the use of these two modes is determined by the characteristics of the experiment. In one-interval paradigms, it is assumed that the context-coding mode is used, and the theory relates resolution to the total range of intensities in the stimulus set. In two-interval paradigms, it is assumed that the two modes are combined, and the theory relates resolution to both the total intensity range and the duration between the two intervals. The theory provides, among other things, a new interpretation of the 7 ± 2 phenomenon.