Relating Sensitivity and Criterion Effects to the Internal Mechanisms of Visual Spatial Attention
Abstract
A recent paper by Muller and Findlay (1987) raises the important issue of how to relate the parameters d' and beta to the internal mechanisms that process visual stimuli. This commentary considers the widely held view that d' changes reflect a variety of mechanisms leading to perception, but that beta changes reflect a single high level decision mechanism that is postperceptual and under conscious control. In a complex highly parallel, multi-level system, both sensitivity and criterion shifts may influence perception in lawful ways - neither being necessarily more basic and important. The paper, raises some methodological considerations that quality Muller and Findlay's results. It is not argued that probability manipulations produce beta shifts in detection tasks and d' shifts in identification tasks is necessarily wrong. The implication Muller and Findlay along with others often draw from this kind of result - that detection tasks involve 'radically' different selection mechanisms than identification tasks is questioned. In the following discussion, the terms d' and beta will refer to the quantities one computes from data collected to the theoretical variables that may underly changes in those measured quantities.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 1988
- Accession Number
- ADA197088
Entities
People
- Gordon L. Shulman
- Michael Posner
Organizations
- University of Washington