Reward is the pleasure of eating that comes form pleasing tastes and smells. Satiety is satisfied by digestion of food. Experiments on rats have suggested that the hypothalamus is the brain structure that controls hunger. Food intake is not only motivated by hunger, but also social factors. Eating is often an important ritual, and the desire to inhibit eating is often a result of social pressures to stay thin.
Emotions are feelings that influence behavior and that have physiological and cognitive elements.
Psychologists, such as Robert Plutchik have done work trying to determine what the basic, core emotions of human experience are. Elkman came up with nine factors that should be present in order to consider an emotion a basic, core emotion. Three of these factors are distinctive physiological arousal caused by the emotion, antecedents of the emotions are the same across cultures, and presence in other primates. William James and Carl Lange believed emotions are simply the result of physiological experience, but this theory has bee largely discredited. Walter Cannon and Phillip Bard proposed that emotions are caused by nerve impulses in the thalamus that simultaneously cause a physiological response.