Effect of varying the gain of a visual display of positional error on some aspects of human tracking performance

Abstract

The effects of varying the gain of a visual display of positional error by a factor of 4 on performance during a compensatory tracking task with zero input were studied. Measurements were confined to the movements occurring at 4–12 c/s. When the display gain was increased from an initial reference setting to 4 times this level, 9 subjects showed a reduction in error amplitude. Statistical analysis showed that this change was significant beyond the 5% or 1% level in 4 of these 9 subjects. One subject showed a small non-significant increase in error amplitude when the display gain was increased. Frequency analysis showed that the change in amplitude (usually a reduction) occurred throughout the 4–12 c/s range. Of the 9 subjects who showed a reduction in error with a high gain display of position, 5 showed a uniform diminution in amplitude throughout the 4–12 c/s frequency range, and 4 showed a relatively marked degree of attenuation of the peak in the spectrum at 7–10 c/s. The possible nature of the mechanism underlying these effects is discussed.