Pursuit Rotor

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Screen shot of PEBL's Pursuit Rotor Task


[edit] About

The pursuit rotor task is a task used in common use in the mid 20th century which involved a participant trying to follow (pursue) a small disc on a rotating turntable. Original mechanical versions had typical rotation rates of 60 RPM, which is probably too fast for mouse-controlled versions. The PEBL version offers a simple version with multiple trials and controllable parameters that can be used as a test of hand-eye coordination.

As with the original test, the main performance metric is time-on target. For a 15-second test, participant may have the cursor on target for perhaps 10 seconds. A second metric output is mean deviation from the target center, in pixels.

By default, there are 4 15-second trials, which means the entire test can be performed in just a minute or two.

[edit] Notes

By default, the task runs for 4 15-second trials. Rotation speed is 1 rotation every 7.5 seconds, for 2 rotations/trial.

In the task, the target changes color from dark red to bright red when the cursor is on top of it, giving extra feedback about correct performance.

By default, the experiment is set to run with a screen size of 800x600 pixels. If your screen does not have a 4x3 aspect ratio, stretching this screen size will create a path that is not a circle. Adjust gVideoWidth and gVideoHeight to choose an appropriate aspect ratio for your computer.

[edit] Options

Edit pursuitrotor.pbl in battery/pursuitrotor.pbl to change options

 * trialtime is the number of seconds per trial (default 15)
 * trials is the number of trials in the experiment (default 4) 
 * gSpeed is the number of rotations/second.  (default is 1/7.5)  Good values seem to be between .1 and .2.
 * gTargSize is the radius of the target (default is 25 pixels)
 * gVideoWidth and gVideoHeight control the pixel size of your screen (default is 800 x 600)  

[edit] Data Output

Data are saved into two files in battery/pursuitrotor/ directory. The file pursuitrotor-X.txt is a moment-by-nmoment log of cursor position. Columns are:

subject_id trial cycle absolute_time elapsed_time targx targy time-on-target  mouseX mouseY inside time_diff ttime_on_target miss miss_total

The file pursuitrotor-report-X.txt save the summary data printed out at the end of the test.

[edit] Norms

A norm study on middle school children is available:

  • Piper, B. J. (2010). Age, handedness, and sex contribute to fine motor behavior in children. Journal of Neuroscience Methods. doi:10.1016/j.jneumeth.2010.11.018

[edit] To Cite

Mueller, S. T. (2012). The PEBL Pursuit Rotor Task. Computer software retrieved from http://pebl.sourceforge.net

[edit] Historical References

  • Adams, J. A. (1952). Warm-up decrement in performance on the pursuit-rotor. The American Journal of Psychology, 404-414.
  • Ammons, R. B. (1955). Rotary pursuit apparatus: I. Survey of variables. Psychol. Bull, 52, 69-76.

[edit] Used PEBL Version

[edit] See Also

PEBL Test Battery

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