Recent research suggests that complex tasks that require self-control to complete, such as strenuous tests or complicated decisions, put a strain on the limited resource known as the ego. The ego is thought to be a kind of mental energy reserve that can be depleted with use. Previous studies have shown that, not only is it possible to deplete the ego, but this depletion leads to poor performance on various later tasks involving skills such as decision making, cognitive extrapolation, reasoning, and self-control. Two models in particular have gained support recently: the resource model –involving blood glucose– and the trade-off model – involving distribution of attention. Because both creativity and the ego are thought to be biologically based and because cognitive flexibility, which has been shown to be highly correlated with creativity, seems to require a fairly high level of processing like other processes on which ego depletion has been shown to have a negative effect, it is reasonable to suggest that ego depletion would cause a decrease in creativity as well.
Butler, Stoni; Little, Jessie; Walter, Dustin; and Phillips, B. Allyson, "Too Tired to Think Outside the Box? An Analysis of Ego Depletion's Effects on Creativity" (2015). Scholars Day. 11.