The Aimed Movement Task has been designed to evaluate Fitts’ Law (Fitts, 1954) and consequently implemented using the PEBL (Psychology Experiment Building Language) system. Fitts’ Law (Fitts, 1954), developed by psychologist Paul Fitts, examines human psychomotor behavior in human-computer interaction. The model states that the time it takes to move or point to a target is dependent on the distance and the size of the target. This predictive model also explains the speed-accuracy trade-off characteristics of the human muscle movements, i.e., faster movements and smaller targets result in higher error rates. Fitt’s Law revolutionized the understanding of electronic systems, focusing on a human channel and the information metrics bits.
Note that the Aimed Movement Task is a computerized, refined, and modified version of the classic Reciprocal Tapping Task, which required the subjects to touch two metal plates with a stylus. In the original task, the size of the metal strips and the distance were altered to test motor capacity.
The Aimed Movement Task has evolved over the years and is now performed on a computer with the help of a mouse. The mouse cursor acts as a pointer moved across the screen towards the target. Now, the test is widely applied in user interface and user experience design. The Aimed Movement Task is easily modifiable for patients with brain disorders and cerebral palsy. For instance, a head-pointer instead of a hand mouse may be used to track the eye movements of patients with reduced mobility.