PEBL Hub — IRB Fact Sheet — 2026-08-23
Fitts' Law Task
motor_control
psychomotor_speed
coordination
Category:Motor
Duration:~8 minutes
Ages:7+
Populations:adults, children, research, HCI, ergonomics
Parameters:12 configurable parameters including test type (3 modes), number of repetitions, target sizes and distances
Version:1.0
Description
Classic motor control task measuring the speed-accuracy tradeoff in rapid aimed movements. Tests the relationship between movement time, distance, and target size, following Fitts' Law (MT = a + b*log2(2D/W)).
Participants rapidly move the mouse cursor from a home position to rectangular targets of varying sizes and distances. Each trial begins at the home position on the left side of the screen. When ready, participants move to the target rectangle as quickly as possible. Movement time and accuracy are recorded for each trial.
Measures: Motor control, pointing accuracy, speed-accuracy tradeoff, psychomotor coordination
Notes
- Three test modes available: OS mouse with warping (native only), graphical cursor with clicking, graphical cursor with dwelling
- Targets vary in size (10-40px) and distance (50-700px)
- Web version uses manual cursor return to home position between trials
Key Parameters
| testtype | testtype == 1: use OS mouse, stop when you click; testtype == 2: move graphical cursor, stop when you click; log xy stream. testtype == 3: trial ends when you stop moving; logs xy stream (default: 2) |
| reps | Number of reps of sizexdistance design (default: 10) |
| allowYMovement | Should y dimension move? (default: 1) |
| targheight | Height of target in pixels (default: 50) |
| startx | Starting x position (default: 50) |
| ShowPreview | Can you see the target before you move? (default: 0) |
| dist1 | Distance of target (default: 50) |
| dist2 | Distance of target (default: 75) |
| dist3 | Distance of target (default: 100) |
| dist4 | Distance of target (default: 200) |
| dist5 | Distance of target (default: 350) |
| dist6 | Distance of target (default: 500) |
| dist7 | Distance of target (default: 700) |
| size1 | Width of target (default: 10) |
| size2 | Width of target (default: 20) |
| size3 | Width of target (default: 40) |
Scoring & Interpretation
| Validation | validated |
| Psychometric data | Available |
| Normative data | Not available |
References
Fitts, P. M. (1954). The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 47(6), 381-391.
MacKenzie, I. S. (1992). Fitts' law as a research and design tool in human-computer interaction. Human-Computer Interaction, 7(1), 91-139.