An element in the visual field is just a conjunction of attributes: a critique of Bundesen (1991)

Nissen (1985) presented results showing that in partial-report experiments, selection by location was different from selection by color or by shape. Bundesen (1991) presented a reinterpretation of these results, claiming that they can also be explained by a model in which location selection is treated on a par with selection by color or by shape. We will show that the analysis given by Bundesen is based on a special relation between an "element" in the visual field and its location, which in fact reduces the expressions given by Bundesen to those given by Nissen. Furthermore, we will show that in Bundesen's theory, it is assumed that in the process of perceptual categorization an element in the visual field can be referred to without the use of one of its attributes. This assumption is untenable from a theoretical point of view. In all, the results presented by Nissen can still be regarded as evidence for the difference between selection by location and selection by color or by shape.