LABORATORY TESTS 137 



philosophy, I carried these tests somewhat further, vary- 

 ing them partly by increasing the number of sheets of 

 paper, partly by decreasing the distance between them. 

 The increase in the number of sheets made only a slight 

 difference in the results. With 200 tests in each case I 

 obtained the following results : 



With but few exceptions, the errors were, as a rule, of 

 one place. The series with an odd number of sheets (5, 

 7. 9) gave better results than those with an even number 

 (6, 8, 10). In the tests with the odd number of sheets 

 the experimenter (K.) stood in front of the middle sheet, 

 so that it was at the apex of a right angle made by the 

 series of papers and the median plane of the subject's 

 body; whereas in the case of the even number of papers 

 the subject stood opposite the space between the two 

 middle sheets, thus making the position of the sheets less 

 favorable. 



In the preceding tests the distance between the centers 

 of the neighboring sheets was always 50 centimeters, so 

 that the angle through which the median plane of the ex- 

 perimenter's body would have to turn in order to pass 

 from one sheet to the next, was about zVa degrees. In 

 the following tests these distances were gradually 

 decreased. The sheets, always five in number, were 

 replaced by ever narrower white strips of paper mounted 

 on dark cardboard and illumined by a Nernst lamp. 

 The following table shows the decrease in correct infer- 

 ences running parallel with the decrease of the angle 

 through which the subject would have to turn in order 

 to be in line with the several pieces of a series succes- 



