46 G. V. HAMILTON 



manifested with invariable advantage is more apt to recur in 

 the behavior of the individual than is a still more frequently 

 manifested response which has not brought invariable advantage. 

 12. These studies suggest a possibility, which they by no 

 means prove, that with descent of the phyletic scale the factor 

 of recency increases in importance as a determinant of habit 

 formation whilst that of frequency relatively decreases. 



APPENDIX 



I. Individual Records of Tw^enty Girls. 

 II. Individual Record of White Rat 5. 

 III. Analysis of White Rat 5's Record (calculations for table 8). 



