Cognitive delay

The Hick-Hyman Law [11,13] states that the time to make a decision based on $N$ distinct choices is given by

$$RT= a +b\log_2N (s)\vspace*{-2mm}$$

Parameters $a$ and $b$ are constants that can be empirically determined. Based on the information in [3], we assume $a$ to be $0$ and $b$ to be $\frac{1}{7}$.

The Hick-Hyman Law can be useful only if the number of different choices, $N$, is known. Unfortunately, it is hard or even impossible to estimate $N$ for many cognitive processes. A menu selection may actually involve more choices for a user than the number of menu items because the user may evaluate the consequence of selecting an item and the possible subsequent choices to decide whether to select that item or not. In this study, we conservatively assume $N$ to be the number of most direct choices like the number of menu items and the number of buttons to choose from.