Eye movements as a function of response contingencies measured by blackout technique.

A program may have a low error rate but, at the same time, require little of the student and teach him little. A measure to supplement error rate in evaluating a program has recently been developed. This measure, called the blackout ratio, is the percentage of material that may be deleted without increasing the error rate. In high blackout-ratio programs, obtaining a correct answer is contingent upon only a small portion of the item. The present study determined if such low response-contingent material is read less thoroughly than programmed material that is heavily response-contingent. Eye movements were compared for two versions of the same program that differed only in the choice of the omitted words. The alteration of the required responses resulted in a version with a higher blackout ratio than the original version, which had a low blackout ratio. Eighteen undergraduates received half their material from the high and half their material from the low blackout-ratio version. The order was counterbalanced. Location and duration of all eye fixations in each item were recorded by a Mackworth Eye Marker Camera. On high blackout-ratio material, subjects used fewer fixations, shorter fixation time, and shorter scanning time. High blackout-ratio material failed to evoke the students' attention.