14 HAROLD C. BINGHAM 



to the discussion which has ensued consists in calling attention 

 to the need of sharper distinction between the study of form 

 discrimination and pattern discrimination. He argues that we 

 should not expect the child to discriminate forms in the sense 

 of my definition. He theorizes that infrahuman animals "have 

 only a more or less crude pattern vision." As a means of test- 

 ing the validity of his theory he proposes that the surroundings 

 of the discriminable forms be changed, since the form, seen 

 with its surroundings, must be considered as part of a pattern. 

 Even if no other objects are in the visual field the stimulus "is 

 seen surrounded by the more or less irregular outline of the 

 field of vision, and so is again part of a pattern." 



To demonstrate experimentally whether the animal is react- 

 ing to forms or patterns. Hunter proposes that the electric 

 chambers of the experiment box be fitted, after a perfect habit 

 has been established, with hollow cylinders or hollow triangular 

 prisms through which the stimuli may be seen by the reacting 

 subject. He presents diagrams which, he declares, represent 

 the discrimination situation in my experiment and in Lashley's 

 study (20) of form perception in the rat. 



Both series of, experiments are concerned with patterns not forms 



In problem boxes such as those described by Lashley and Bingham .... 

 the animal tested is confronted not by two "forms'^ corresponding to the configura- 

 tions of the opal glass, but by such designs as are suggested in figure 1. The 

 squares drawn in the figure represent the rectangular tunnels down which the 

 animal goes in making his responses. What the animal sees is a triangle or a 

 circle each in more or less of a square setting. 



Designs 4 and 5 represent Laskley's "forms." 



Johnson (14) points out that Hunter's proposed method of 

 control would introduce new olfactory stimuli and probably 

 new tactile stimuli. Is there any means of deciding, he asks, 

 whether failure to discriminate, after making such a change, 

 resulted from the change of pattern or from the simultaneous 

 introduction of other novelties? Furthermore, Johnson be- 

 lieves the change of a form stimulus from the right to the left 

 compartment of the experiment box actually changes the back- 

 ground and foreground. This would therefore make the pat- 

 tern a variable and the form a constant. 



In addition to Johnson's reply to Hunter's contention, I have 

 pointed out (3) the impossibility of pattern, in Hunter's sense, 



