LABORATORY TESTS 103 



of some simple problem in addition. Then I would 

 begin to tap, — but in human fashion with my right hand, 

 rather than with my foot — and continued until I be- 

 lieved that I had perceived a final signal. I thus tested, 

 all in all, twenty-five persons, of every age and sex (in- 

 cluding children of five and six years), differing also in 

 nationality and occupation. None of them was aware 

 of the purpose of the experiments. It could not escape 

 them, to be sure, that they were being watched. It was 

 also evident to them that the things noted were certain 

 tensions and movements; but none of my subjects dis- 

 covered what the particular phenomena were that I was 

 looking for. Only in a few isolated instances did they 

 report that they were conscious of any movements on 

 their part. With the exception of two persons, they all 

 made the same involuntary movements which were de- 

 scribed in chapter II, the most important of which was 

 the sudden slight upward jerk of the head when the final 

 number was reached. It was at once evident that the di- 

 rection of this jerk depended upon the position which one 

 had asked the subject to assume at the beginning of the 

 test, the direction changing whenever the position was 

 changed. Thus, if the subject stood with head bowed — 

 the body either being held erect or likewise bowed, — then 

 release of tension would be expressed physically by an 

 upward jerk. (Occasionally the entire trunk is slightly 

 raised, so that it was possible to observe this physical 

 reaction when standing behind the subject). If the sub- 

 ject had bent his head backward, the " psychological mo- 

 ment " was marked by a forward movement, (although 

 under certain conditions the head was, in such a case, 

 observed to bend still farther backward). If during the 

 tests the head was bent slightly to the right, then the re- 



