1. Tactual Localization of a Point. --Mark off an area 50 millimeters wide and 100 millimeters long from the wrist upward, on the volar (inner) surface of the forearm by ink-dots at the corners of the parallelogram. Make a similar plot in the note-book. Working within this area, touch O, who sits with eyes closed, lightly with the point of a pencil and require him to try to locate this spot, eyes opened, by touching with another pencil.* Mark the relative positions of the two spots by dots in the note-book plot, and connect them by a light line to indicate the magnitude of the error. Label the dots S (stimulus) and L (location) respectively. Make 15 trials. Record O's analysis of what constitutes the "local sign"--the terms in which he recognizes the location of a touch.†
There are three factors in the record: the measurement of accuracy of localization in terms of the magnitude of the error; the direction of the error; and the analysis of the local sign.
Accuracy of localization varies for different parts ofthe skin; in general, the portions of the skin which are____________________