The time it takes to make a decision increases with the number and complexity of choices.
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.
Productivity soars when a computer and its users interact at a pace (<400ms) that ensures that neither has to wait on the other.
Peak - End Rule
People judge an experience largely based on how they felt at its peak and at its end, rather than the total sum or average of every moment of the experience.