AN ANALYSIS OF THE LEARNING PROCESS IN THE SNAIL 73 



slightly when touched with the hair, showed conclusively that 

 the tactile stimulus was effective. A series of check tests in 

 which this stimulus alone was used showed that the irritation 

 thus caused was not severe enough to make it serve as a punish- 

 ment. Six snails were used and the usual method of recording 

 and curve plotting was followed. 



TABLE XII 



Showing the number of correct-by-chance, correct-by-association, and incorrect 

 trials in a series of tests in which an electric shock was used as punishment in 

 connection with a mechanical warning stimulus. The Y apparatus was used with 

 the arms shortened to 3 cm. and 1.5 cm. In case of error in choice the snail was 

 stroked across the dorsal head region with a hair and then given an electric shock. 

 The apparatus was cleaned between tests. Four individuals of Physa gyrina Say 

 were used. 



Snail No. 9 

 No. of No. of Choices Choices 



No. of trial trial correct correct 



days for for by by Incorrect 



tested series day chance association choices 



Totals. 



Totals. 



Totals. 



10 

 11 

 12 

 13 



14 

 15 



16 

 17 

 18 

 19 

 20 

 21 

 22 

 23 



Totals . 



24 

 25 

 26 

 27 

 28 

 29 

 30 



1 



2 



3 



3a 



4 



5 



6 



7 



1 

 2 

 3 

 4 

 5 

 6 

 6 



1 



2 



3 



3a 



4 



5 



5a 



6 



8 



1 

 2 

 3 

 4 

 5 

 6 

 7 

 7 





 1 

 

 

 

 

 



1 







2(22' 



o) 





 



1 





 



1 



2 (33%) 



1 

 1 

 

 

 

 

 



1 



3 (37%) 





 1 

 

 1 

 1 

 1 

 1 

 5(71%) 





 

 

 

 

 

 

 

 

 







1 







1 

 1 







3 (50%) 





 

 



1 





 





 



1 (12%) 



1 

 



1 





 

 







2(28%), 



1 

 

 1 

 1 

 1 

 1 

 1 

 



1 



7 (77%) 



1 

 

 

 

 

 

 1 (16%) 





 



1 







1 

 1 

 1 







4 (50%) 





 

 

 

 

 

 

 



