Some psychologists describe this effect as “ego-depletion,” meaning that higher-level cognitive areas involved in executive function and planning (for example, the prefrontal cortex) get fatigued. Willpower is a limited resource; we run low on it, just like a tank of fuel. In the case of the judges, the more cases they had to make decisions about (up to thirty-five in one sitting) the more energy-depleted their brains became. But after eating something like a sandwich and a piece of fruit, their energy stores were refueled and different drives had more power in steering decisions.
