There are two types of psychometric function: A theory of cue combination in the processing of complex stimuli with implications for categorical perception.

Abstract

Psychometric functions are customarily fitted using normal distribution functions. However, categorical perception identification tasks give functions that are more sigmoid than the normal distribution (M. Treisman, A. Faulkner, P. L. N. Naish, & B. S. Rosner, 1995). This can be explained by a theory of discrimination, cue combination theory (CCT), presented here. This theory assumes that complex stimuli (e.g., speech sounds) are composed of components or cues that vary in informativeness. The decision mechanisms sample individual cue dimensions and combine the information from each. The model generates a normal psychometric function if all cues sampled are informative. If not, the function becomes more sigmoid. CCT offers accounts of discrimination (categorical and continuous) and sensory reaction times, adaptation, sequential effects, contextual effects, trading relations, speed and accuracy, perceptual learning, and the separable-integral distinction.

A cross-linguistic examination of assimilation context effects

“…He argues that speech perception fundamentally involves a process of feature cue parsing in which temporally distributed acoustic feature value cues are grouped and integrated into unitized feature representations that may be aligned with segmental positions. The notion of feature cue parsing is consistent with evidence concerning the distribution of feature cues (Bailey & Summerfield, 1980;Stevens, 1998), the finding that listeners integrate multiple cues to the same feature (Best, Morrongiello, & Robson, 1981;Hodgson & Miller, 1996;Parker, Diehl, & Kluender, 1986;Repp, 1982;Sinnott & Saporita, 2000;Summerfield & Haggard, 1977;Treiman, 1999) and evidence that listeners may be induced to misalign acoustic feature cues with segmental representations (Repp, 1978). The feature cue parsing view suggests that English place assimilation is best viewed as a process that intermeshes feature cues associated with neighboring segments, and argues that the resultant featural ambiguity is resolved as a natural product of the feature parsing process.…”

Longitudinal relationships between speech perception, phonological skills and reading in children at high‐risk of dyslexia

“…Average relationships remain unclear. Categorical speech perception tasks require both perceptual and decision-making skills (Treisman, 1999).…”

Is signal detection theory fundamentally flawed? A response to Balakrishnan (1998a, 1998b, 1999)

“…But d9 can also be embedded in a theoretical context in which it estimates a parameter of a model, since SDT allows us to frame models of underlying processes and estimate their parameters. An advantage of this approach to understanding psychological processes is that it allows predictions to be made and tested and it allows us to relate the results of different types of psychophysical procedures (Swets, 1964;Treisman, 1999;Treisman & Watts, 1966). S9 cannot serve these purposes.…”