Abstract
This study examines the phenomenon of colour-preference in sorting tasks exhibited by dementing patients, comparing their performance with that of young and elderly normal adults, and patients with depression and focal brain damage. Twelve experiements explore the role of selected variables in producing colour-dominated behaviour in demented patients factors which predispose the subject to select the colour mode for solving classification problems include the personality trait of extraversion, mental rigidity, interference from irrelevant stimuli in both one and two dimensions, perceptual difficulties produced by integral dimensions of the stimuli, the training effect from previous experience, the nature of the verbal instructions given prior to the task, the number of categories employed and the cognitive complexity of the form stimuli. Factors expected to influence colour dominance, but proved not to do so, included colour salience and inequality of sorting categories (unless the difference was gross). In a separate series of studies, the value for differential diagnosis in psychogeriatric patients of a number of verbal and non-verbal psychometric tests, namely, the Graylingwell Information test, Gresham Ward Questionnaire, Weigl Colour-Form Sorting Test and the Organic Integrity Test, is examined. Multifactorial analysis enables a more efficient modification of the verbal tests to be made, and new sorting systems applied to the non-verbal tests achieves the same ends. The theoretical and psychometric considerations of this work are discussed, and some practical implications for psychogeriatrics are mentioned.