MAZE STUDIES WITH WHITE RAT 285 



time. The actual records secured in any experiment will thus 

 be a function of the relative strength of the two tendencies. 

 In one type of situation the sensitive function may be the more 

 effective in determining the character of the records, while the 

 adaptive function may be the more efficacious in another experi- 

 mental situation. The two experiments which deviated from the 

 usual rule were rotation of maze and rotation of cage. The 

 average error score of the normals was less than that of the blinds 

 with the exception of the maze rotation experiment. We have 

 here a rotation in reference to a predominantly optical situation, 

 and one would expect that the sensitive function of the eye 

 would predominate in effectiveness; the disturbance is so great 

 that the corrective effects are not sufficient to reduce the error 

 record below that of the blind animals. When the test was 

 repeated, we find that the normal groups made the greater 

 adaptive progress, and reduced their error score below that of 

 the blinds. When the corrective function is given time to 

 become efficacious, the error records no longer constitute an 

 exception to the rule. When the cage was rotated, normal 

 animals were not affected by a 15-min. exposure, while the blind 

 rats were. We may explain this difference in susceptibility on 

 the hypothesis that the corrective function of vision enabled the 

 normal animals to resist the disturbing effects of the new con- 

 ditions. With a 24-hr. exposure both groups wejre affected, but 

 the blinds manifested the greater disturbance and the normals 

 exhibited the greater tendency toward adaptation. The normal 

 rats thus were no longer able to resist the cumulative effects 

 of a prolonged exposure, but the corrective function of vision 

 enabled them to reduce the degree of the disturbance and hasten 

 adaptation. 



The corrective and sensitive functions of vision are also evi- 

 dent from a comparison of the records of normal rats in the 

 different experiments. When the maze was rotated in reference 

 to a stationary heterogeneous environment, the normal animals 

 were exceedingly disturbed but they made marked progress in 

 adaptation when the test was repeated. A rotation of the 

 maze and a uniform optical environment gave a lesser degree 

 of disturbance and no tendency toward adaptation. The dif- 

 ference in the two alterations was presumably optical in the 

 main. The greater the optical changes, the greater was the 



