ABSTRACT
The peripheral area around the central fixation point from which specific information can be extracted and processed is the visual lobe area or useful field of view. The size of this area depends, among other things, on characteristics of the visual target and the surrounding context. A special measurement technique of analyzing the visual field, used to estimate mental work load, was evaluated by Voss. He analyzed performance in peripheral vision by presenting peripheral light stimuli for detection. The visual stimulus material was generated by this computer and presented by the Videograph, whch is a color video display controlled by a microprocessor, on a TV screen. In other words, the fixations on visual search material of low difficulty have a higher probability of being followed by the target fixation than on visual search material of medium or high difficulty. The concept of the visual lobe area as defined and measured by the relation of successful and unsuccessful fixations.
