Lab1: Human Performance, Fitt's Law

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Note:2 or more subjects required. Can be students themselves.

Paul Fitts found a predictable relationship between the size of a target, the distance we have to move to it, and the speed at which we can tap, point at, click, or whatever on it. Today we'll do experiments to try to determine this relationship. The typical Fitts' Law experiment involves alternating tapping on two targets. Another variant involves targets appearing randomly in a field, and tapping those.

• The first experiments you'll do will involve measuring Fitt's Law using good old pencil and paper. The tapping task template can be found here:

  Tapping task template.

  Print out a number of these and run at least two people (not yourself) on the experiment described. If you've got time, run lots of people.

• To continue with pencil and paper, now run a number of people on the signature task:

  Signature task template.

• For the final set of experiments, you'll use the Fitts' Law "IDTest" from IBM Almaden.
  Measure any two devices of choice (e.g. large vs. small mouse, mouse vs. trackball, touchpad vs. trackpoint, mice with very difference shape)

  Analyze and compare performance of the two devices

  HINTS:

  Find tasks with big differences between devices.

  IDTest.exe produces a text file called IDTest.dat. Rename it, save it, ship it home, copy it into a spread sheet.

  Plot time vs DI (ID?); compare to Fitts' model (intercept+slope*time).

  You shouldn't need the sources, because we've already installed it on the lab machines. In case you'd like to try to run these on your own machine at home, here are the files.

  Source files for Lab 1 Java program from IBM.

  You may have to thrash around with java to get things to work, though. Better to run it in the warm, secure, and comfortable HCI Lab.

• Compare your device results with hand/pencil results.

• Discuss the validity/benefits of Fitts' Law in your study.

• Discuss pros and cons of the devices: suggest improvements or new designs

The ID Test is written by Shuman Zhai's colleague (and manager) Barton Smith, in Java, partially for this class. You can download it Here

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CS377a/MUS252: HCI Technology Stanford University, Autumn 1999

CS 436: HCI Technology Princeton University, Autumn 1999

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