Using tachistoscopic test data from previous experiments, a simple method of calculating visual lobe size was found to give results comparable to those obtained with a more complex method using linear regression of transformed data, An experiment using Hong Kong Chinese subjects is reported, in which the first trial of a card-sorting test gave highly significant correlation with lobe dimensions. With some modification, the test could provide a simple, rapid and reliable means of determining relative lobe area. Lobe area is known to be an important visual function for search performance, and the simple test proposed may prove useful as a selection and training aid for tasks involving monitoring or quality assessment.