Human hunger as a memory process

Hunger refers to: (1) the meaning of certain bodily sensations; (2) a mental state of anticipation that food will be good to eat; and (3) an organising principal, which prioritises feeding. Definition (1) and (2) is the focus here, as (3) can be considered their consequent. Definition (1) has been linked to energy-depletion models of hunger, but these are no longer thought viable. Definition (2) has been linked to learning and memory (L&M) models of hunger, but these apply just to palatable foods. Nonetheless, L&M probably forms the basis for hunger generally, as damage to declarative memory can eradicate the experience of hunger. Currently, there is no general L&M model of hunger, little understanding of how physiology intersects with a L&M approach, and no understanding of how definition (1) and (2) are related. We present a new L&M model of human hunger. People learn associations between internal (e.g., tummy-rumbles) and external cues (e.g., brand-names) and food. These associations can be to specific foods (episodic memories) or food-related categories (semantic memories). When a cue is encountered, it may lead to food-related memory retrieval. If retrieval occurs, the memory’s affective content allows one to know if food will be good to eat now - hunger - a cognitive operation learned in childhood. These memory processes are acutely inhibited during satiety, and chronically by multiple biological parameters, allowing physiology to modulate hunger. Implications are considered for the process of making hunger judgments, thirst, the cephalic phase response, and motivational and lay theories of hunger.