FEBRUARY 9, 1912] 
to determine in a relatively small number 
of trials the character of the prospect that 
an individual may have for acquiring skill 
in any given activity. The plasticity may 
be measured in this way for any of the 
motor processes of musical training.. If 
but a single measure of plasticity is to be 
made, this may well be on the traiming in 
xceuracy of transition from one note to 
ynother, involving the elements of release 
and attack. 
As regards intensity of tone production, 
we are interested in the natural streneth 
and yolume of the tone and in the volun- 
tary control of these factors. The strength 
of tone is expressed in terms of amplitude 
of vibration and should be measured in 
representative parts of the register. In so 
far as they differ from strength, carrying 
power and volume may be judged essen- 
tially in terms of the mode of tone produc- 
tion. Voluntary control of the strength of 
tone may also be measured in terms of the 
amplitude of the vibration. The measure- 
ment of voluntary control in the making of 
fine differences in volume, or in the change 
of volume as distinct from intensity of 
tone, is too complicated for our present 
purpose, but systematic observation of this 
in ordinary singing is essential. 
Motor ability may be measured in terms 
of the degree of accuracy in the rapid 
enunciation of a selected list of syllables. 
The form of the attack is also an excellent 
measure of time-efficiency in musical ac- 
tion. But the most important of all time 
measurements is of course the ability to 
sing in accurate time and rhythm. For 
time alone, we test the singing of equal 
durations without accent. For rhythm, in 
the true sense, the singing must be with 
time and intensity variables together as in 
ordinary singing. The measure should be 
made for both simple and complex rhythm.® 
5Tn measurements of motor ability, and rhythm 
in actual singing, the dictograph or some similar 
SCIENCE 
205 
A number of tests may be grouped under 
the general head of association, and these 
may be subdivided somewhat arbitrarily as 
in the outlined list. We should first se- 
cure a quantitative picture of the relative 
vividness of images from the different 
senses. Then the auditory image should be 
tested for fidelity, stability and relevance, 
in such a way as to reflect the role and 
power of auditory imagery in singing. 
The same may also be done for motor 
imagery. 
The most fundamental fact about mem- 
ory is the memory span for musical tones. 
This may be measured in terms of the 
number of tones (taken from a single oc- 
tave, but not forming a known melody) the 
individual can remember for immediate 
reproduction or recognition. The power 
of retention may be measured by determin- 
ing roughly the extent to which the singer 
can recall music heard a day or a week be- 
fore. The power of musical redintegration 
may be tested by observing to what extent 
the individual can recall, in their true 
setting, the fine details of a complex musi- 
eal production. Here the phonograph can 
be used to good advantage. 
Association type may be given as the 
name for the sampling of the mental con- 
tent and the prevailing mode of reaction 
as determined by free association experi- 
ments in what is now called psychoanalysis. 
This will show, for example, whether the 
individual lives in music objectively or if 
the music is to him merely a series of af- 
fective stimuli which arouse a feeling of 
idealized beauty. Most of the relevant 
facts which may be determined objectively 
by such diagnostic association tests may, 
however, be obtained by the expert through 
direct and unaided observation. 
To the musical mind the sounds group 
themselves in large units, such as themes, 
movements, phrases, ete. The power of 
instrument may be used to excellent advantage. 
