INTERACTION EFFECTS IN THE LATERAL VISUAL -FIELD - AN EXTENSION OF BOUMAS (1970) APPROACH

The recognizability of a letter is impaired by the presence of additio nal letters. This phenomenon is called lateral masking. Proceeding on the assumption of Bouma (1970) lateral masking can be described in ter ms of retinal eccentricity of the target letter and the distance betwe en target and flanking stimuli. In this paper, we will adress to the q uestion if these kinds of parameters are adequate for describing later al masking effects. For this purpose, characteristics of the string li ke its length and its homogenity are varied. The subject's task is to identify the central letter of a tachistoscopically presented string. The targets in the string are flanked both by only x and by different randomly selected letters. Additionally, we varied the length of the s tring. The data show that these variations influence the strength of t he masking effect. It is concluded that a pure sensorical approach is not sufficient for an explanation of lateral masking effects.