HABIT FORMATION IN FROGS 331 



the tongue two caterpillars — possibly four (see record for July 26). 

 The habit was formed very rapidly. Is it necessary therefore 

 to assume the presence of concomitant psychic processes, such 

 as mental images, for example, to explain satisfactorily how 

 such rapid learning could be accomplished? It seems to be 

 generally considered by animal and htmian psychologists that 

 the very rapid formation of a habit, that is, one requiring very 

 few experiences to form it, denotes a higher grade of intel- 

 ligence (mental activity) than the slow formation of a habit. 



Cases of very rapid lea-rning sometimes appear when the 

 stimulus is very disagreeable or even painful, in which case 

 high intelhgence is not necessarily denoted. For this is perhaps 

 largely a physiologic reaction — a shock — usually causing cessa- 

 tion of general activity, inhibiting most of the normal activities 

 of an animal, as is illustrated by the behavior of Rana clamata 

 (medium) when stimulated by the electric current. Not only 

 was the eating of cockroaches inhibited, but the ingestion of 

 all food was suspended for several days. Therefore, this is 

 not an instance of actual learning, for no discrimination resulted. 

 Instead, all chance for discrimination was obliterated. It thus 

 becomes a simpk matter to decide whether very rapid modi- 

 fication of behavior is due to physiologic shock or to actual 

 learning. If the application of a stimulus causes heightened 

 discrimination, actual learning is indicated ; if the process of 

 discrimination is lowered or obliterated, physiologic shock is 

 indicated. The behavior of the frogs toward the hairy cater- 

 pillars differs entirely from the reactions of the frogs to the 

 electric stimulus, for the modified behavior affected only the 

 caterpillar which gave the disagreeable stimulus. Compared 

 with the strength of the eating instinct the caterpillars were 

 only mildly disagreeable, for the frogs made several tests in 

 quick succession. We have therefore to deal here with actual in- 

 telligence and not with physiologic shock. 



Did the frog on seeing the hairy caterpillar, after the avoiding 

 habit was formed, recall the previous disagreeable experience 

 with it? Miss Washburn writes that "where the learning is 

 very rapid this always remains possible." But " where the 



process is slower the simpler hypothesis would be that 



the pleasure and pain of the results operate directly on the 



