Given the Hick’s Law equation of RT = 290 + 100[log2N], what reaction time would be expected for 16 choices. Provide you answer in milliseconds and do not include units in your answer.

Delivering a good user experience requires that first you find out the functionalities that will answer their needs; second, you need to guide them to the specific functions they need most. If users end up stuck in the decision-making process of “what next?”, they may become confused, frustrated, or leave your website.

Hick’s Law is a simple idea that says that the more choices you present your users with, the longer it will take them to reach a decision. It’s common sense, but often neglected in the rush to cram too much functionality into a site or application. As a designer, you will use Hick’s Law to examine how many functions you should offer at any part of your website and how this will affect your users’ overall approach to decision making.

What Is Hick’s Law?

Hick’s Law (or the Hick-Hyman Law) is named after a British and an American psychologist team of William Edmund Hick and Ray Hyman. In 1952, this pair set out to examine the relationship between the number of stimuli present and an individual’s reaction time to any given stimulus. As you would expect, the more stimuli to choose from, the longer it takes the user to make a decision on which one to interact with. Users bombarded with choices have to take time to interpret and decide, giving them work they don’t want.

The formula for Hick’s Law is defined as follows:

RT = a + b log2 (n)

Where “RT” is the reaction time, “(n)” is the number of stimuli present, and “a” and “b” are arbitrary measurable constants that depend on the task that is to be carried out and the conditions under which it will be carried out. “A” could be finding the right present online for your mother-in-law; “B” could be an onscreen chat with your mother-in-law in which she reminds you it’s her birthday tomorrow.

Generally, the application of Hick’s Law is simple – reduce the number of stimuli and get a faster decision-making process — but there are exceptions to the rule. For example, a user may already have made a decision before seeing the stimuli. In that instance, the time it takes for him/her to act is likely to be less than if he/she had not already determined a course of action.

The Implementation of Hick’s Law

You can find applications of Hick’s Law everywhere, not just in web and app design. Hick’s Law determined the number of controls on your microwave or your washing machine. A design principle known as “K.I.S.S.” (“Keep It Short and Simple”) became recognized in the 1960s for its effectiveness in this regard. Echoing Hick’s Law, K.I.S.S. states that simplicity is the key for a system to work in the best way. First embraced by the U.S. Navy, the principle of “K.I.S.S.” was in general use in many industries by the 1970s. In some environments, K.I.S.S. gets translated as “Keep It Simple Stupid”.