Page:Popular Science Monthly Volume 40.djvu/769

 attention is perfect, while the movements are unusually direct and extensive. The originator of this record is the best of our subjects, in the sense that the involuntary movements are largest and most predictable.

We may substitute reading from a printed page for the naming of colors and obtain a very similar result. An example is given in Fig. 3, showing, as before, the movement of the hand toward the object of attention.



The attention may be directed to a sound as well as to a visual impression; this may be conveniently done by listening to the strokes of a metronome. In order to further strengthen the attention the subject is required to count the strokes, the usual rate being one hundred and forty per minute.



The result—a typical illustration is given in Fig. 4—shows that the hand moves toward the metronome. If the metronome be placed in front of the subject in one experiment and behind him in the next, an interesting contrast may be observed. The effect of close attention to the regular strokes of a metronome may show itself in another way. We all appreciate how strong is the tendency to beat time to enlivening music, by tapping with the hands, or stamping with the feet, or nodding with the head; and Dr. Lombard has shown that music is capable of effecting such thoroughly involuntary movements as a sudden rise of the leg when the patella of the knee is struck. It is not surprising, therefore, to find evidences of periodic movements in these automatograms, and in some instances, such