10 HAROLD C. BINGHAM 



wheat without pecking at the glued rice. The observers had 

 two quantitative measurements for the rapidity of learning: 

 (1) The number of series necessary for a perfect habit; (2) the 

 number of reactions to rice. To make sure that the errorless 

 chicks did not avoid the rice by means of the glue which might 

 be visible on the pasted kernels, the rice was scattered loosely 

 upon the cardboard in the same manner as the wheat. The 

 wheat w^as again eaten by the errorless chicks and the rice was 

 left. The discrimination, the authors concluded, was between 

 wheat and rice. 



Having found that the chick could pick up wheat and avoid 

 rice, Katz and Revesz sought an answer to the question: By 

 what means does the chick discriminate the grains? Accord- 

 ingly they turned to a study of size and form discrimination. 

 Because the chicks could be trained to eat only half grains of 

 rice when scattered among whole grains, the authors were con- 

 vinced that there was discrimination of size and form. Further 

 observation leads them to conclude that the chick discriminates 

 squares and triangles. They say: 



Knowledge of this fact we secured through a variation of the experimental pro- 

 cedure. Out of green peas (some of which had been readily eaten), we cut three 

 and four cornered pieces. On account of their moisture, they could not be glued 

 down, so we laid the four sided pieces upon a glass plate and the three sided pieces 

 under it. The chick found that the three sided pieces could not be reached and 

 soon ceased to peck at them. Then if we laid both forms upon the glass plate, 

 only the squares were picked up. By means of the same method we found that 

 the chick discriminates between triangles and circles as well -as squares and 

 triangles. 



The report of Katz and Revesz leaves the reader too often 

 uncertain of the experimental conditions. They have tried to 

 do too much and have not treated any one task intensively. 

 Their report indicates carelessness and indifference to details. 

 No doubt the assertion that the chick discriminates squares and 

 triangles as well as triangles and circles is true for the conditions 

 under which the experiment was made. But from the written 

 account, one cannot tell what the conditions were. One does 

 not know, for example, the relative sizes of the different forms. 

 Were they equal in area? Was the square an inscription or a 

 circumscription of the circle? Was the diameter of the circle 

 equal to the side of the square or the altitude of the triangle? 



