ACKNOWLEDGMENTS 



Any psychological merit which this paper may possess is due 

 entirely to the teaching and inspiration of Professor James R. 

 Angell under whom I have worked. I am glad also here to 

 acknowledge my obligations to Professor Harvey Carr for help 

 in many ways in the animal experimentation and to Professor 

 J. B. Watson, now of the Johns Hopkins University, for advice 

 and encouragement. 



