1907] Jennings. — Behavior of the StarfisJi. 153 



a better insight into the problem by inquiring as to just what 

 phenomena formed the basis of this idea, than by merely crying 

 out against anthropomorphism, or by showing on the basis of 

 definitions made since the time of the author in question, that 

 he is wrong. Preyer's view that the brittle star shows intelli- 

 gence in this behavior is evidently due to the fact that the 

 animal does not move at random, but sets to work by such a com- 

 bination of activities as is actually well fitted to remove the 

 source of irritation. Preyer could therefore argue that the 

 action requires something like an understanding of the relation 

 of means to end. and this indeed in a somewhat complicated 

 combination; this (he would say) requires intelligence. Preyer 

 would be further confirmed in this view by the fact that when one 

 of these well-directed combinations of movements is not success- 

 ful, another is tried. 



To Preyer's characterization of this behavior as intelligent, 

 of course the objection can very properly be made that it does 

 not fulfill the objective definition or test for intelligent action 

 that is now commonly accepted (see Glaser, 1907). But this 

 does not do away with the actual problem which Preyer had in 

 mind, — namely, how does the brittle-star happen to be able to 

 make so purposive a combination of movements, in circumstances 

 that required it? This seems to require at least something like 

 what Driesch (1903) has more recently characterized as "ob- 

 jective knowledge". A similar problem comes up in connection 

 with the righting reaction, and it will there be more fully dis- 

 cussed (see p. 173). The older investigators would probably 

 have maintained that the use of these purposive combinations of 

 movements (in cases that clearly do not come under the accepted 

 definition of instinct), requires that they should have been reached 

 by such adaptive modifications as would come clearly under even 

 the modern objective definition of intelligence. 



But of course it will not do to abandon the direct experi- 

 mental test for adaptive modifiability and Glaser (1907) has 

 recently repeated these experiments of Preyer to see if such 

 modification can be demonstrated. He repeated the experiment 

 with the rubber tube many times on the same individual, to see 

 whether it would improve in removing the tube. — either by 



