Mickey Mouse's negative affect facing mistakes.

Many of the scientists working in the field of 'animal behaviour' and especially of 'animal cognition' consider the most obvious factors for fitness maximization - for instance, nutritional reward maximization - as the sole motivators when a course of action must be chosen. Sweis, Thomas, and Redish (2018, PLOS Biology, 16(6), e2005853) show that even in a food-restricted environment in which it is vital to maximize food gaining, other factors, not obviously linked to fitness, play a role for decision-making - in the present case, avoidance of a negative affect linked to changing one's mind (a factor which does not improve foraging efficiency), and individual flavour preference (a factor which even impairs foraging efficiency).