Fitts's Law Task

Introduction

Eye-hand coordination is a complex and crucial process by which we respond to visual stimuli. For instance, when reaching for a coffee cup in front of you, you unconsciously gauge the distance between your hand and the cup before moving to grab it. This seemingly simple action has been extensively studied by psychologists interested in motor control and eye-hand coordination.

INFO: While this may appear trivial to adults, observing how babies develop their eye-hand coordination reveals its complexity. Although it is instinctive for adults, infants spend months refining these skills.

In the 1950s, American psychologist Paul Fitts explored the difficulty of moving our hands toward an object, and his mathematical model, known as Fitts's Law, quantifies this process. Fitts's Law is widely recognized in psychology and neuroscience, drawing inspiration from the laws of physics. Today, however, psychologists seldom refer to "laws" in this context; instead, they use various equations to describe motor control patterns, based on experimental parameters (see the Wikipedia page for more details).

Fitts's Law specifically addresses how long it takes to move a hand toward an object, asserting that the time it takes to perform a movement is a function of the object's distance and size. For example, it takes longer to grasp a small object that is farther away than a larger object at the same distance. On the other hand, a smaller object nearby can be just as easy to grasp as a larger object placed further away.

The essence of Fitts’s Law

Movement Time = Log2( Distance / Size + 1 ) (Shannon form, as computed by this implementation)

About this implementation

Fitts's original study focused on one-dimensional movement. However, this task extends the model to two dimensions.

After the experiment is finished, an XY plot will be generated based on the data collected from your 20 trials. The plot shows how closely your movement times follow Fitts's Law.

Run the demo

In each of the 20 trials, follow these steps:

1. Move the mouse cursor to the small yellow rectangle at the top-left of the screen, then click the left mouse button once.
2. A red rectangle of random size will appear. Your task is to move the cursor as quickly as possible into the red rectangle and click inside it.