50 HARRY H. WYLIE 



negative response, the curves for the learning of the posi- 

 tive response show none of these pecuHar features. In the 

 positive curves there is evidence of learning from the very 

 beginning, the process is quite gradual until completed, 

 the process is quite irregular, showing both lapses and 

 plateaus, and when learning is once completed, the stand- 

 ard is not so consistently maintained as in the negative. 

 Since the general situations in the two problems were quite 

 alike and the specific stimuli used (light and sound) were 

 quite alike, the different character of the responses required 

 must be largely the cause of the striking differences in the 

 learning curves. It is to be remembered that the negative 

 curves for sound do not stand out in as great contrast as 

 the other negative curves. 



