Hunger in the Chemical andNon-Chemical Senses

There are two main forms of hunger (i.e. desire to eat): appetitive (food cues lead to hunger) and interoceptive/temporal (internal bodily/time cues lead to hunger). The focus here is to examine how these hungers relate to the chemical and non-chemical senses. Appetitive hunger arises from perceiving food cues via vision, olfaction and audition. This results in memory retrieval about the perceived food, both of its flavour/affect during eating and its consequences. The processes that take place when a visual/auditory food cue is perceived are different to those that occur when an olfactory food cue is perceived. An olfactory food cue automatically generates a mental image of its associated flavour (sensation and affect) while visual or auditory food cues require more controlled processing, and if a mental image is formed, they may draw more upon the affective nature of the eating experience. For interoceptive/temporal hunger, this involves a wide variety of internal bodily sensations and time, but how these translate into hunger is not so well understood. However, when hunger does occur it may be more akin to that resulting from visual/auditory food cues. Differences in hunger processing between olfaction and the other senses are discussed.