Laws and Hypotheses for Behavior 269 
to A D instead of the original A B C D, the law of the 
resolution of physiological states would be relevant to only a: 
fraction of learning. For example, let a cat or dog be givert 
an ordinary discrimination experiment, but so modified 
that whether the animal responds by the ‘right’ or the 
‘wrong’ act he is removed immediately after the reward or 
punishment. That is, the event is either S Rr or S Ra, 
never S Ri R2. Let the experiment be repeated at inter- 
vals so long that the physiological state, St. Rr, or St. R2, 
leading to the response Rr or Rz in the last trial, has 
ceased before the next. The animal will come to respond to 
S by Rz only, though R2 has never been reached by the 
‘resolution’ of S Rr Ra. 
Cats in jumping for birds or mice, men in playing 
billiards, tennis or golf, and many other animals in many 
other kinds of behavior, often learn as the dog must in 
this experiment. The situation on different occasions is 
followed by different responses, but by only one per 
occasion. Professor Jennings was misled by treating as 
general the special case where the situation itself includes a 
condition of discomfort terminable only by a ‘successful’ 
response or by the animal’s exhaustion or death. 
Assuming as typical this same limited case of response 
to an annoying situation, so that success consists simply 
in replacing the situation by another, Stevenson Smith 
reduces the learning-process to the law of exercise alone. 
He argues that, — 
“For instance, let an organism at birth be capable of 
giving N reactions (a, b,c, . . . N) to a definite stimulus 
S and let only one of these reactions be appropriate. If 
only one reaction can be given at a time and if the one 
given is determined by the state of the organism at the 
time S is received, there is one chance in N that it is the 
