Many psychological experiments are designed to examine the impact of a specific variable (in the case of this paper: sleep deprivation) on different facets of human functioning (in the case of this paper: decision making). To examine this impact scientifically, two groups (also called conditions) are compared: the experimental condition in which the variable of interest is present (i.e., sleep deprivation) and a control condition in which the variable is not present (i.e., a well-rested group). Apart from the variable of interest, both conditions have to be as similar as possible. The difference in functioning (i.e., decision making) between both groups informs about the impact of the variable under study.
defined by Jan Alexander Häusser