Hick's Law

Hick's law, first proposed in 1952, states that response times increase in proportion to the logarithm of the number of potential stimulus-response alternatives; it is expressed in the equation TR+a+b{Log2 (N)}. In other words, the more choices you have to chose from, the longer it takes for you to make a decision.

Although, Hick did not state a certain number of milliseconds it takes to decide between options, nowadays, most researchers believe that the time it takes to decide on an action is about 150 milliseconds. Since there are 1,000 milliseconds in one second, this means it takes about a tenth of a second to decide on one action. Since each addition choice effectively doubles the decision time, if you have two choices, it will take about 300 milliseconds to make a decision; three choices will take about 600 milliseconds, etc.

While I was a design student at NC State University in the 1960's, I remember studying a football training method that was used to train quarterbacks to make instantaneous throwing decisions. A coach made a helmet that had an opaque visor that could be raised or lowered by pulling on a long cord attached to the back of the helmet. The quarterback wore the helmet and stood ready to throw the football with the visor down. Three receivers began to run patterns, the quarterback was told which receiver to throw to, the visor was raised by the coach for a tenth of a second, and then it was lowered. In that tenth of a second, the quarterback had to locate the correct receiver and compute all the throwing parameters, since he had to throw the ball after the visor had dropped. During the action of game, the time a quarterback had to make his throwing decision was very large in comparison to the tenth of second used in the training exercise.