Spaulding, Association in Her j nit Crabs. 6i 



the "constructs" of two "sense fields," vision and taste. The 

 existence of this association is proved by its effectiveness in 

 subsequently bringing about, with only one stimulus presented, 

 the same reaction against a natural positive heliotropism, as pre- 

 viously occurred with two stimuli present. The reaction here 

 is therefore conditioned internally, as well as externally. The 

 internal condition must be identical with either the excitation 

 of, or with that and the reproduction from the "after-effect" of 

 the second, the "taste-stimulus;" if there is only excitation 

 then the internal event is only physiological ; if there is also re- 

 production then it is psychical as well as physiological. 



Both interpretations agree equally well with the data ob- 

 tained, for the reason that even in the second case there must 

 be a physiological basis for the psychical events if present, and 

 consequently, the two being quite compatible as ultimately reg- 

 ular and uniform series of events, there is theoretically no cer- 

 tain objective criterion for the presence here of consciousness. 



Practically there is, however, such an objective criterion 

 which we make use of in our intercourse with other men, and 

 if the above data are interpreted in as strict analogy to this as 

 possible, it seems justified to consider that the Hermit Crab 

 "reproduces" or, if one will, remembers vaguely. 



The author, as a holder of one of its "research rooms" at 

 Woods Hole wishes to acknowledge his indebtedness to the 

 Carnegie Institution for the opportunities thus presented for the 

 carrying on of this and other investigations. 



Jan. 12, igo^. 



