painful experience felt during intense hunger owing to contraction of the stomach. The definite sensory experience arising out of this gastric contraction is known as hunger pang. But this physiological condition is neither the chief nor the sole factor of hunger.The body, according to its needs, as is abvious in animal's behaviour, seeks food and selectsfood. Either due to some metabolic disorder or due to the deficiency of some diet the systemfeels hungry and satiates its 'specific hunger' with the particular food in demand. This 'specific hunger', according to physiological psychology, are of many kinds which may not have any connection with the contraction of stomach walls. In such cases we eat, though the stomach may be full. In some pathological cases the patient whose stomach has been removed had shown desire for food and ate normally. Many children due to abnormal habits or internal disorders are so fond of sweets that at the very sight of a sweet they want to eat, no matter how full the stomach may be. Morgan and stellar have cited illustrations of 'pregnancy and lactation', 'endocrine factors' 'vitamin deficiencies', etc.., as the sources of specific hungers. From these observations it is proved that gastric contraction; though one of the factors of hunger, is not essential to it.
Some psychologists have, therefore, made a distinction between hunger pangs and hunger-as-appetite. Psychology however, understands hunger in both senses. By hunger are meant both the sensation-pattern of the hunger pangs as well as the motive to eat.