Specific and General Effects of Brain Injury in Man: Evidence of Both from a Single Task

Introduction  In several reports from this laboratory,^4,7,8 it has been pointed out that penetrating brain wounds in man tend to have twofold effects on behavior: specific effects, restricted to cases of injury in certain locations,^4,5 and general effects, which appear after injuries, irrespective of their site.^6,8 Until now, separate tasks have been necessary to demonstrate either kind of effect; the present report deals with a single experimental situation yielding evidence for both.The experiment is based on a classical perceptual task (first used by Aubert in 1861), that of setting a luminous line to the apparent vertical when the subject is tilted in a dark room.^1,2 Under conditions of moderate body tilt (up to 30 degrees) to his right, a normal adult makes constant errors by setting the line too far to the left of the plumb line, and conversely for body tilts to the left.