PATTERN-DISCRIMINATION IN VERTEBRATES 



185 



TABLE 4 

 Threshold Conditions for Chick 2 



Remarks 



TABLE 5 

 Threshold Conditions for Monkey 2 



1 . 774 mm. 

 *1.561 " 



0.890 " 



*0.780 " 



0.610 " 



*0.520 " 



0.413 " 



*0.390 " 



0.321 " 



*0.312 " 



0.232 " 



*0.223 " 



0.190 " 



0.796 " 



*0.780 " 



*1.561 mm. 

 1 . 301 " 



*0.780 " 

 0.673 " 



*0.520 " 

 0.479 " 



*0.390 

 0.371 



*0.312 

 0.304 



*0.223 

 0.210 



*0.173 



*0.780 

 0.750 



14 



17 



14 

 14 



17 

 8 



5.9 

 4.9 



2.9 

 2.6 



4 

 5.8 



9.8 



2 

 3.8 



15.5 



14 

 11.5 



5.4 

 2.8 

 4.9 



Note training-effect 



2.9 Note training-effect 



* Standard stimulus. 



COMPARISON WITH HUMAN SUBJECTS 



A comparison of the relation between the absolute stimulus- 

 value (expressed in terms of width of striae on the standard 

 field) and the minimal effective differences for the animals with 

 that obtained for human subjects is of some interest. Accord- 

 ingly I determined this relation for two human subjects by means 

 of the method of limits, using the same visual conditions as for 

 the animals. The magnitudes of the thresholds obtained on 

 the human subjects by the method of limits are not to be com- 

 pared with those obtained by the discrimination-method on the 

 animals. A threshold-value obtained by the method of limits 



