466 POPULAR SCIENCE MONTHLY 



tedious, and would demand a greater amount of space than this 

 magazine could be expected to furnish. The nature of the objections 

 to the article can, however, be made clear without so comprehensive and 

 minute an examination. 



Let us, in the first place, take a single one of the tests, that relating 

 to the size of the moon : 



My next question did not refer to immediate perception, but to a memory 

 image so vividly at every one's disposal that I assumed a right to substitute it 

 directly for a perception. I asked my men to compare the size of the full 

 moon to that of some object held in the hand at arm's length. I explained the 

 question carefully, and said that they were to describe an object just large 

 enough, when seen at arm's length, to cover the whole full moon. 



The answers ranged from a carriage-wheel to a pea; and on this result 

 Professor Miinsterberg makes a number of interesting comments. 

 " To the surprise of my readers, perhaps," he says, " it may be added 

 that the only man who was right was the one who compared it to a 

 pea. It is most probable that the results would not have been different 

 if I had asked the question on a moonlight night with the full moon 

 overhead. The substitution of the memory image for the immediate 

 perception can hardly have impaired the correctness of the judgments. 

 If in any court the size of a distant object were to be given by witnesses, 

 and one man declared it as large as a pea and the second as large as a 

 lemon-pie and the third ten feet in diameter, it would hardly be fair to 

 form an objective judgment till the psychologist had found out what 

 kind of a mind was producing that estimate." And elsewhere he refers 

 to the fact that his students do not know " whether the moon is small 

 as a pea or large as a man." 



Now, this experiment, damaging as Professor Miinsterberg con- 

 siders it, has, in point of fact, no bearing whatever upon the perceptive 

 powers of his students. If they understood perfectly what his question 

 meant, and shaped their answers accordingly, those answers were the 

 outcome of some kind of conscious mental calculation or experimenta- 

 tion (unless, indeed, we suppose that some of the students, for example 

 the one with the pea, had made the explicit experiment of the obscura- 

 tion of the moon by an object held at arm's length, and remembered 

 the result). There is absolutely nothing in our direct perception of 

 the moon to give us any idea of the angle it subtends, or of the size of 

 an object which, held at arm's length, would " just cover it." Pro- 

 fessor Miinsterberg is, indeed, in this dilemma : either he wants to know 

 what the intuitive feeling of a given man is as to the apparent size of 

 the moon when he looks up at it, or he wants to know just what he 

 explicitly declared — what object, held at arm's length, would cover it 

 from the eye (i. e., one eye). If he means the former, the intuitive 

 feeling, each person is the final arbiter of the question — he is either 

 lying or telling the truth; the moon either does or does not seem to 



