DELAYED REACTION 69 



conduct, and on this hypothesis the assumption of the effective 

 presence of after-images is an explanatory luxury. 



3. Motor attitudes of orientation as cues of response. The 

 data of the preceding section conclusively prove that main- 

 tenance of orientation during delay was an essential condition 

 for correct response with the rats and dogs, and that such motor 

 attitudes exerted a strong influence upon the behavior of the 

 raccoons. Either these attitudes serve as the substituted cues 

 and control conduct directly, or they function indirectly as a 

 means of support to some such cue as an after-image. The 

 evidence unambiguously favors the first supposition. These 

 orientation attitudes, like any sensory process, may be a stim- 

 ulus to definite movements. This tendency of the animal to 

 run in the direction of their orientation at the moment of re- 

 lease was natural and habitual. The tendency was present in 

 full strength at the beginning of the experiment. The tests 

 merely developed the maintenance of orientation for longer and 

 longer periods. This fact indicates that the motor attitude 

 functions directly upon subsequent conduct. If the attitudes 

 were but a means of support to some other cue, one would 

 expect that this relationship of means and end would need to 

 be acquired gradually during the experiment. An alternative 

 theor}^ presents many theoretical and factual objections. Any 

 such roundabout and forced type of explanation is entirely 

 unnecessary when we know that motor attitudes are a natural 

 guide to the direction of subsequent responses. The mechanism 

 of such a cue may be entirely automatic and mechanical. It 

 requires nothing more for its explanation than does any habit. 

 A stimulus initiates a certain act whose completion is prevented 

 by external means. This initial activity persists unchanged so 

 far as its directional aspect is concerned until the raising of the 

 release permits it to function in a normal and habitual manner. 



4. Some unknown intra-organic cue non-observable by the 

 experimenter. Our data prove conclusively that some such 

 cue was utilized by the raccoons and the children. Our proof 

 of this statement is based upon the method of exclusion and 

 the nature of such a factor must necessarily be defined at pre- 

 sent in negative terms. We have exhausted our ingenuity as 

 to objective possibilities of explanation, and as a consequence 



