Project XS-F2-U25

Some 5,000 persons, one by one, climbed into the driver's seat, took hold of the steering wheel, put right foot on the accelerator, left foot on the floorboards, looked at the green traffic light in the pillar before them. The scene was not a highway but the psychological laboratory of Massachusetts State College at Amherst, or the 1935 Boston automobile show, or the 1934 Eastern States Exposition at Springfield, Mass. When the person being tested put his foot on the accelerator, the cam of a motor selector switch was set revolving, turning the green light to amber in two seconds. Thereafter, at an unpredictable interval, the amber light turned red. As soon as he saw the red light the subject removed his foot from the accelerator, applied the brake. The time interval was electrically measured. The average reaction time was .43 sec. The fastest was .26 sec. The slowest was .90 sec. It was found that tall persons generally react a little more slowly than short people, no doubt because motor nerve impulses travel through the body at about 300 ft. per sec. and thus for tall persons the motor impulse would take longer to go from the brain to the foot. Another theory is that short people simply have less leg to deal with.

This test was a prime part of Project XS-F2-U25--a scientific investigation of driving skill begun with $14,000 of FERA funds last September under the direction of Professor Harry Reginald DeSilva. Born 37 years ago in Pensacola, Fla., Harry DeSilva got a Ph. D. from Harvard, another from England's Cambridge, lectured at Canada's McGill. When he took charge of Massachusetts State's psychological laboratory three years ago, he was an imaginative, and mechanical-minded scientist, disillusioned with what he calls "pencil-&-paper" psychology and with antiquated gadgets which had changed little since Germany's Wundt, father of experimental psychology, devised them half a century ago. Dr. DeSilva studied the most modern apparatus he could find in the U. S. and abroad, became convinced that he could measure ability to handle a motor car with considerable precision. Last week he polished up a report of his work under FERA, prepared a request for funds to continue his research under WPA.

Dr. DeSilva believes that the dismal U. S. toll of injury, death and property loss exacted by automobile accidents (TIME, Aug. 12) is largely due to the fact that entirely too many drivers take their driving for granted, fail to assess and try to improve their skill as they would if they were fishermen or golfers or chess players. He scoffs at the typical test for an operator's license, in which a bored policeman rides slowly around the block with the candidate, who meets no emergency and performs nothing more difficult than turning around in a dead-end street or backing into a parking space. Laboratory tests would compel the candidate to demonstrate ability to cope with all sorts of situations, would eliminate as factors the strictness or leniency of the examining officer. Finally, Dr. DeSilva urges that laboratory equipment helps beginners learn in safety and provides them with accurate progress reports.

Quickness. The time it takes for brain and muscles to respond to a situation seems to be part of an individual's natural endowment, like sensory or temperamental defects. In Dr. DeSilva's brake test, assiduous practice brought some improvement, but never more than one-tenth of a second. Since all persons, whether slower fast, can improve the same amount. practice thus does not change the ranking. The average person's reaction time quickens to a peak at about 25 years of age, after which there is a steady decline.

Steering. In this test, the driver sits in an automobile cab and looks at an imitation highway, the scenery moving past him on each side and the road underneath. An irregular cam keeps the hood of his "car" bobbing off the road, a "situation" that must be corrected by use of the steering wheel. Scores are on the basis of percentage of time the car is kept on the road. Men with six to ten years of driving experience steer best, and better than women. But women continue to improve as long as they drive, and after about 25 years of handling a car they have the edge on men of the same age and experience.

Speed Estimation. The subject sits before an apparatus showing two miniature cars moving from left to right, the rear car traveling the faster. Before it overtakes the one in front the two cars disappear behind a low screen bearing a scale. The subject is asked to estimate the point on the scale at which the cars pass. The average error is about four inches, some subjects erring as much as 20 inches. The general tendency is to pick a point somewhat short of the actual overtaking point.

Vision. Dr. DeSilva gave his subjects tests for visual keenness, color perception, "tunnel vision" (inability to detect movements from the side when looking straight ahead), depth perception (estimation of distance). A prime vision test was that for "glare blindness." The subject looked into an illuminated box. What he seemed to see was a car with glaring lights approaching on the left and the light of his own lamps illuminating the right side of the road. The subject was asked to turn a dial, increasing the power of his own lights, until he could make out the dim figure of a pedestrian in front of him. Some people could not see the figure no matter how much they turned up their lights. The psychologist found that most of these "glare-blind"' persons were unaware of their defect, believing that everyone else had the same difficulty.

Judgment When further funds are available, Dr. DeSilva plans to have the subject confront motion picture films showing a moving roadscape. Unexpected things will happen--cars will back suddenly out of driveways, pedestrians will dart across, two cars will approach abreast--and the psychologist will observe the driver's response.

For the present, to test judgment, he works with an apparatus which has two endless belts moving over a narrow table about 20 ft. long, representing a quarter-mile of highway. One belt carries cars approaching on the left, the other cars receding on the right. The driver can pass the cars going in his direction by pressing the accelerator (altering the speed of the belt) but he must estimate their speed and distance properly and be careful of oncoming cars. If he makes a miscalculation, there is a loud crash and the windshield swings back violently.

Few weeks ago Dr. DeSilva announced invention of a portable device which records the speed of passing cars instantly. From one side of the road two parallel beams of light, 18 inches apart, play into photoelectric "eyes" on the other side. An automobile traveling in either direction interrupts one beam first, the other a tiny fraction of a second later. This small interval is electrically measured, translated into miles per hour and read off on a dial at once.

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