Some recent work in multidimensional scaling has focused on the psychological processes involved in making the responses required by mathematical theory. Messick and Abelson tentatively classified scaling theories in terms of the subjects' psychological processes. Shepard found subjects' processes involved in a variety of tasks to be a function of proximity along the stimuli. Other models involve a generalization of Coombs' unfolding technique; direct ratio scaling methods resulting in scalar products derived as a basis for factor analysis. Multidimensional scaling has been applied in widely different uses, including studies of facial emotions, perceptions of political leaders, social dimensions of a jury table, confusion errors in language recognition, and preferences of artists, heroes, saints, and scholars. Gulliksen and Tucker proposed an approach to unidimensional scaling to reduce the large number of judgments required by each subject. New approaches to analyzing individual differences have also been proposed recently. Also, the computer shows promise in developing models. Several reviews have been published on multidimensional scaling. There are still limitations in current expertise, and further empirical research is needed.