Measuring Hand/Eye Coordination

Scientists in the middle of the 20th Century developed several well-known pieces of laboratory equipment to study motor performance. Of particular interest was hand-eye coordination, the ability of humans to make complex hand movements that were adjusted to a continually changing visual input. Hand-eye coordination is required in many skilled tasks. Hand-eye coordination is required in many skilled tasks. Individual differences in this ability affect the performance of people in work and recreational settings such as assembly jobs and playing sports.

One widely used piece of machinary for studying hand-eye coordination was the pursuit rotor apparatus, shown in the following illustration.

What is the pursuit rotor task?


A pursuit rotor apparatus

A pursuit rotor consists of a turntable-like platter with a metal spot on it. The subject holds a wand with a metal tip. The subject tries to keep the tip on the metal spot (activating the timer) as the platter turns. To do this, the subject must track the circular movement of the turntable. The speed of rotation can be varied, to see how this affects the amount of time that the tip spends in contact with the metal spot on the platter.


A mirror tracing apparatus

What is mirror tracing?

A second tool commonly used to study motor control is the mirror-tracing apparatus. A subject is given a design, such as a star, to trace with a pencil. The subject views his or her hand in a mirror while a barrier blocks direct sight of the hand.

The mirror reverses and disrupts normal visual-motor coordination. Initially, the hand (seen in the mirror) moves in ways opposite to what the subject expects. People gradually learn to reverse the normal hand-eye relationship, and with practice they become increasingly adept at mirror tracing. Mirror-tracing was used to study the abilities of the famous memory patient H.M., to demonstrate that he could learn from practice sessions even though he remembered nothing of the sessions themselves.


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Copyright © 2007 Russ Dewey