Age-related effects in delay discounting for food

Abstract

Developmental influences of growth, such as hormones and metabolic factors, increase food intake and weight across the lifespan. Delay discounting (DD), a choice procedure that characterizes preferences for immediate rewards, such as food, over larger, more delayed ones may be useful in understanding developmental and metabolic changes in decision making processes related to food intake. The present study examined the relation between age and food DD in a cross-sectional design. Other variables, such as pubertal stage, were examined also as these may influence discounting. Participants (N = 114; 28 children and 86 adult) from a community sample completed measures of food and money delay discounting to determine if age-related variation in discounting tendencies is food-specific or more general. Both measures yield an omnibus discounting value and three additional values for small, medium, and large magnitudes. Analyses first revealed magnitude effects-- smaller magnitudes of both food and money were discounted more steeply than larger magnitudes. Hierarchical regressions indicated subjective hunger predicted steeper food discounting. When subjective hunger was controlled, age, but not puberty, significantly predicted food discounting for omnibus, medium, and large magnitudes of food. In children, food discounting decreased from early childhood to late adolescence. In adults, food discounting increased from early to late adulthood. Neither age, puberty, nor obesity status predicted any measure of monetary discounting. Food discounting, then, appears to change across the lifespan, and therefore, may be appropriate to examine psychological processes that accompany developmental and metabolic changes across the lifespan.