INDIVIDUAL DIFFERENCES IN IMAGERY. 



CHAS. H. GRIFFITTS. 



An historical survey of the literature dealing with this topic reveals three 

 separate lines of investigation. The first begins vs^ith the work of Fechner, 

 who described the visual imagery of several persons, was carried further by 

 Galton, and later by others who used modifications of Galton's questionnaire. 

 These investigations have covered but one phase of the problem, which is that 

 of the individual differences to be found in the clearness of "concrete" 

 imagery. 



The second line deals with the quantitative aspect of "concrete" imagery. 

 It began with the work of Ribot and Dugas, who determined the kinds of 

 images aroused by lists of selected words. More of this work has been car- 

 ried on in Germany than elsewhere. 



The third is concerned with the quantitative aspect of "verbal" imagery. 

 It began with the observations of Charcot, and with the controversy between 

 Strieker and Egger, with regard to the relative importance of the auditory 

 and kinaesthetic elements in inner-speech. 



From about 1880 to about 1910 it was generally uncritically assumed that 

 the person who was found to be "visual" in one connection would also be 

 "visual" in each of the other two. But about 1910 it began to be recognized 

 that with the great majority of persons the concrete imagery is predomi- 

 nantly visual, and the verbal predominantly inner-speech (auditory-motor). 

 This fact, along with the inability to find examples of the supposed "pure" 

 types, brought this "pure type" period to a close. 



Although it was noticed that visual imagery predominates in concrete 

 imagery and inner-speech in verbal imagery, the exact relation between the 

 two has never been determined. It may be that those with the greatest per 

 cent of visual imagery in the first will also have more than the average in the 

 second, even though it ranks second to inner-speech in the latter. 



Nor has the relation between the qualitative and the quantitative aspects 

 (that is, between clearness and frequency) been determined. A positive corre- 

 lation has been generally assumed, but exceptions have been reported. At the 

 present time, therefore, the three separate lines of investigation have never 

 been brought together in a way that enables us to determine what the inter- 

 relations between them may be. It was my purpose to do this in order to 

 determine the nature and extent of individual differences in imagery and the 



21st Mich. Acad. Sci. Kept., 1919. 



