Secondary Task as a Measure of Mental Effort: A Reappraisal

Abstract

Secondary tasks have been seen as a useful measure of the mental effort required by blind pedestrians during independent travel. A comparison is reported of secondary task performance and walking speed for routes of varying complexity. The expected relationship between route complexity and worsening of performance on the secondary task was found. However, reference to the data on gait showed that secondary task performance was only detrimentally affected when the subject contacted obstacles, whereas walking speed was reduced on the more complex routes even when the subject was not in contact with obstacles. Thus, the relationship between secondary task performance and route complexity would appear to be not so much an effect of mental overburdening as it is a result of disorientation.