This paper describes a study of factors that determine the perception of gastric motility. Our interest in this phenomenon was aroused by the results of an earlier investigation of the correlation of gastric motility and reports of hunger,7 which confirmed the Cannon-Carlson thesis that persons of normal weight tend to report "hunger" in the presence of gastric motility, as measured by an intragastric balloon, and
"no hunger" in its absence.3,4 This study revealed, further, that many obese persons do not make this association: their reports of hunger tend to be determined not by the presence or absence of gastric motility, but by a response bias. Many obese men reported hunger most of the time, whereas many obese women reported no hunger most of the time.
These findings raise the question whether some obese persons are unable to perceive gastric motility. Such an incapacity,