The ultimate level of causation refers to the behavior’s evolutionary significance; how the behavior enhances reproductive fitness. The proximate cause refers to the immediate cause of a behavior, whether that be hormonal, neurological, cognitive, interpersonal, or cultural. For example, the proximate cause of humans eating more cookies, cake, and ice cream involves the psychological tendency to desire and enjoy foods with high sugar and fat content. The ultimate cause involves the high caloric content of both sweet and high fat foods, which promotes physical survival in resource-scarce environments.
