Effects of degree of obesity, age of onset, and weight loss on responsiveness to sensory and external stimuli.

Four experiments tested responsiveness to external and sensory stimuli in female human subjects who differed in degree of overweight and in age of onset of their obesity. The effects of weight loss upon external responsiveness were assessed by testing subjects before and after weight reduction in order to determine the role of energy deficit and deprivation in mediating heightened responsiveness to external cues. There was no significant positive correlation between degree of overweight and degree of external responsiveness. In general, the age of onset of the obesity was also not a relevant factor in the degree of externality. Weight loss did not change responses to visual and cognitive cue salience manipulations in measures of feeding, emotionality, time perception, and short-term recall, whereas responsiveness to variations in palatability increased following weight reduction. While external cue responsiveness does not appear to result from adiposity per se or from deprivation, responsiveness to taste stimuli may reflect these parameters. The role of external and sensory cues in the development and maintenance of obesity is discussed.