1897.] Psychology. ; 913 
The experiments on memory, whether made collectively on an as- 
semblage of persons, as (e. g.), on an entire class of students, or individ- 
ually upon single subjects, or again on the experimenter himself, who 
serves as his own subject—these experiments, I say, consist chiefly in 
giving the subject a certain impression, and then seeking to find out 
what becomes of this impression in his memory at the end of a certain 
time. The experimenter endeavors above all to take account of the 
greater or lesser transformation which the memory causes the impres- 
sion to undergo. To discover this, three principal methods are em- 
ployed. 
1. Method of reproduction—This consists in making the subject 
reproduce his impression ; if it is a story that he has listened to, he re- 
peats or writes it ; if it is a visible form, he sketches it; if it is a sound 
or an inflection, or some visible movement, he imitates it; if it is a 
color, he reproduces it by mixing the tints on a palette or varying the 
sectors of rotating discs. This is certainly the most natural method, in 
that it follows closely our ordinary procedure; but as a method of 
studying the memory it is somewhat indirect; it requires a translation 
or transposition of the impression, and a special aptitude, e. g., in 
sketching or painting; it should, therefore, be expressly reserved for 
the verbal memory. 2. Method of selection.—This consists in the rec- 
ognition of the impression when it is presented again in company with 
others; thus a tint is exhibited at first and the subject must remember 
it; at the end of a certain time he is shown a graded series of the same 
color, comprising fifteen different tints, and must recognize the one 
which was shown him before; the second presentation may give the 
whole series simultaneously or successively. This method is simpler 
than the preceding, since it bears more directly on the memory ; there 
remains to consider the sources of error which it contains. One has 
already been noted. Whenever we have to make a choice from among 
a set of objects our attention is drawn towards the centre of the series ; 
if the impression to be recognized is the sixth in a series of 15, the 
Seventh impression is more apt to be indicated than the fifth, because 
the former is nearer the centre; consequently the arrangement of the 
Series, that is, the application of the method, exerts some influence upon 
the character of the results. 3. Method of comparison.—The subject 
compares the remembered impression with another impression which is 
shown him, and answers that the latter is “equal, greater or smaller.” 
* This classification of the methods for the study of memory was first proposed 
by V. Henri and myself; Baldwin has arrived at analogous methods quite inde- 
pendently. 
