Previous research has revealed important differences in architectural evaluation between design professionals and the lay public, with such differences commonly assumed to be the result of professional education. However, few attempts have been made to determine the actual source of such differences, and there is little evidence that these are actually the result of training or education. This paper summarizes the findings of a study which set out to investigate these issues, specifically focusing on differences in architectural interpretation between the lay public, planning students, and practicing planning professionals, a group often neglected in studies of environmental aesthetics. These interpretations were examined utilizing multiple sorting and ranking procedures, with the respondents asked to sort fifteen examples of contemporary architecture according to criteria of their own choice. The results revealed both commonalities and differences in evaluation between the various groups, with the differences particularly pronounced between planners and the public. The results lend support to the view that education is a key factor in the acquisition of aesthetic values and also suggest that training encourages homogeneity of aesthetic tastes. This study thus corroborates and expands the findings of studies by other researchers by suggesting that there are significant relationships between expertise, attitude, and interpretation which may have important implications for planning practice.