The purpose of this study was to determine whether modifying photographic illustrations used for concept-learning by emphasizing defining attributes improves learning by individuals exhibiting various degrees of field-dependence. Concept-learning in this instance refers to identifying objects based on visual characteristics. The specific questions addressed were: 1) Does emphasis of attributes improve concept attainment in general? and 2) Does attribute emphasis provide a differential advantage to field-dependent students, who generally do not perform as well on visual tasks? The relative levels of field-dependence of 115 participants, recruited from the university and surrounding community, were assessed using the Group Embedded Figures Test (GEFT). Three levels of field-dependence were identified: an "indeterminate" level centered on the mean GEFT score for the group; field-dependent, those scoring more than 1/2 standard deviation below the mean; and field-independent, those scoring more than 1/2 standard deviation above the mean. Participants partook of one of two computer-based lessons on the identification of four maple tree species based on the appearance of leaves. One lesson (the control condition) was illustrated with plain photographs, the other with photographs which had been modified using digital image editing to emphasize the critical attributes of each leaf. Following the lesson, each participant took a computer-based, 15-item multiple choice test on identification, and then a second 20-item test requiring identification of mounted leaf specimens. Bartlett’s test for homogeneity of variance revealed that the values in the six cells were not equal. Therefore, the test scores were analyzed using two-way t-tests for samples with unequal variances. All analyses were performed at the 0.05 significance level. Results of the analyses suggest that attribute emphasis does improve learning by individuals in general, particularly when considering transfer. However, no evidence of specific benefit for field dependent learners was revealed by the results. The author concludes with suggestions for further investigation of the benefits derived by various types of attribute emphasis and also the extent to which attribute-emphasis techniques may improve learning for tasks other than concept attainment. / Ph. D.