244 Animal Intelligence 
dividing line, since there is no clear gap between those 
activities which naturalists have come to call behavior and 
the others. 
The discussion will include: First, a description of two 
laws of learning; second, an argument to prove that no ad- 
ditional forces are needed — that these two laws explain all 
learning; and third, an investigation of whether these two 
laws are reducible to more fundamental laws. I shall also 
note briefly the consequences of the acceptance of these laws 
in one sample case, that of the study of mental evolution. 
PROVISIONAL Laws OF ACQUIRED BEHAVIOR OR 
LEARNING 
The Law of Effect is that: Of several responses made to 
the same situation, om, those which are accompanied or closely 
followed by satisfaction to the animal will, other things being 
equal, be more firmly connected with the situation, so that, 
when it recurs, they will be more likely to recur; those which 
are accompanied or closely followed by discomfort to the ani- 
mal will, other things being equal; have their connections with 
that situation weakened,-so that, when it recurs, they will be 
less likely to occur. The greater the satisfaction or discomfort, 
the greater the strengthening or weakening of the bond. 
_The Law of Exercise is that: Amy response to a situation 
will, other things being equal, be more strongly connected with 
the situation in proportion to the number of times it has been 
connected with that situation and to the average vigor and dura- 
tion of the connections. | 
These two laws stand out clearly in every series of ex- 
periments on animal learning and in the entire history of the. 
management of human affairs. They give an account of 
learning that is satisfactory over a wide range of experience, 
