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WALTER S. HUNTER 



I feel that my point with respect to problem boxes is clear. 

 It remains to indicate further that the same hypothesis is applic- 

 able, a priori, to discrimination under natural conditions. "Form" 

 discrimination is always pattern discrimination. If an animal 

 sees a triangular object, the object is not alone. It is either 

 projected against some other "objects" in the background and 

 hence is a part of a pattern, or it is seen surrounded by the more 

 or less irregular outline of the field of vision and so is again part 



Figure 2. Control stimuli which should be used in the study of form percep- 

 tion in order to bring out the influence of the shape of the backgrounds upon 

 the discrimination. 



of a pattern. 6 (To be sure it is an assumption to say that the 

 animal can perceive this outline; but until experiments have 

 indicated either the existence of the more abstruse form percep- 

 tion or have determined the influence of the background upon 

 which the "form" is projected, the assumption may be held 

 as probably valid.) This influence of the shape of the field of 

 vision upon the form of objects can be readily demonstrated by 

 the reader upon himself. Hold a medium sized book about a 

 foot from the eyes. Fixate the book steadily and confine the 

 attention to noting the visual pattern of the whole experience. 

 What one gets is almost as distinct a pattern as is shown in 



• Kulpe (Outlines, pp. 365-366) suggests a similar influence of the form of the 

 visual field upon illusions. This theory has been tested to some extent on humans 

 by C. W. Valentine (Brit. Jour. Psych., vol. 5, pt. ,1) with negative results. 



The perception of form has been studied by several students by means of objects 

 set up in the natural environment or habitat. However, such work has never 

 taken cognizance of the points here brought forward. 



