Hunger and Decision-Making: State-dependent learned valuation in humans

State-dependent learned valuation seems to be an important factor in decision-making across species, however has not been investigated in humans yet. In our study, we could show that a sample of 16 male students aged 20 to 30 years preferred candies of exactly the same color that had been presented to them before in a state of hunger. In two training sessions, a simple board game was played: Whenever volunteers reached a specific field on a two-dimensional parcours, they received a chocolate drop from a bowl in which 50% of either red or yellow chocolate drops representing the two index colors, and 50% of indifferent colors were assorted. One training sessions was preceded by a standardized test meal, the other training session took place in a state of hunger with no meal since breakfast. During a test session, they played the same game but were invited to choose the chocolate drops themselves from a bowl in which we had put both index colors (30% each) and 40% of indifferent colors. Volunteers chose the color that was predominant during the hunger-associated training session significantly more often than the satiety-associated color (p < 0.05). While the difference between ghrelin levels during learning sessions did not seem to be related to preference of the hunger-associated color at retest (r = 0.3, p > 0.2), insulin levels during learning showed a slight trend to predict the color choice in the retest session (p = 0.11, Bonferroni-corrected).