Evidence for the Role of Attentive Fields in Masking

A masking task was employed to determine whether predictions derived from the attentive-field postulate of assimilation theory could be verified. The distance between masking and test lines was varied both towards and away from the center of the attentive field. As predicted, masking was greater when the mask was near the center of attention than when it was located at the periphery of the field. A variation of the mathematical formula developed previously to predict visual illusions was employed to fit the individual and group functions found in this study.

Attentive Fields: Valid Scientific Constructs or Elusive Theoretical Entities: A Reply to Pressey

Pressey conveys the impression that we misunderstood and misapplied his construct of attentive field. In this rejoinder it is argued that by Pressey's own definition and application of this construct his theory should be able to account for our results.

Assimilation Theory, Attentive Fields, and the Müller—Lyer Illusion

The assimilation theory of geometric illusions was employed to predict changes in the outgoing and ingoing forms of the Müller—Lyer illusions as a function of attentive field size. It was found that the theory predicted correctly the form of the function relating amount of illusion and size of attentive field only for the outgoing Müller—Lyer. For the ingoing illusion the prediction was opposite to the empirically obtained results. The findings are seen as additional evidence for the untenability of a unitary theory, such as assimilation theory, for both versions of the Müller—Lyer illusion as they fail to account for substantial differences between them.

The Locus of Maximum Weighting within Attentive Fields: An Empirical Investigation

Fixation within a modified Poggendorff display was used to assess Pressey's hypothesized construct of attentive fields. In Experiment I the results for fixating near the bottom of the display supported the predictions based on Pressey's construct; however, results from fixating near the top of the display were more easily explained by a tilt effect noted by Zajac (1957). Experiment II and III replicated the first experiment and obtained independent measures of the tilt effect. After the tilt effect was subtracted from the Poggendorff scores, the prediction based upon the attentive field construct was supported in the top fixation condition; however, only Experiment II provided support for the prediction in the bottom fixation condition.