“Yes, they have more weight,” as Ernest Hemingway might have said.
But they differ in other ways too. In a study of Columbia University students, Schachter, Goldman and Gordon (1) measured consumption of crackers in a supposed test of the effect of tactile sensation on taste, which was in fact, designed to determine the effect of emotion and fullness on eating behavior.
The students were classified according to weight, height and deviation from the norm in the ratio of weight to height. Students weighing 15% above the norm for their height were classified as obese (fat versus thin). Subjects were required to miss a meal before the experimental session, and were either fed roast beef sandwiches (full condition) or not fed (empty condition) before the initiation of the experiment.
The tactile stimulus, so subjects were told, would be an electric shock. Before administration, some subjects (calm condition) were told that the shocks would produce only a mild tingling sensation or, perhaps, would not be felt at all. Other subjects (frightened condition) were shown an eight-foot-high, jet black console loaded with electrical junk and told by the experimenter “That machine is the one we will be using. I am afraid that these shocks will be painful. To affect your sense of taste, they must be of a rather high voltage. There will, of course, be no permanent damage.” The subject was then connected to the console by attaching a large electrode to each ankle and asked in the process “You don’t have a heart condition do you?” (Devising Psych experiments must be a lot of laughs).
So prepared, subjects expected to do taste tests both before and after the administration of electric shocks. The pre-shock test consisted in a 15 minute session during which subjects tried five kinds of crackers, eating as many as they wished and recording their impressions about the taste on a complicated assessment sheet. After the pre-shock taste test, the experiment was terminated and the rationale for the study explained to the subjects.
The experimental measurement of principal interest was the weight of crackers consumed.
The results were remarkably clear-cut. When calm, thin subjects eat almost twice as many crackers on an empty stomach than on a full stomach (28 versus 17). When frightened, however, thin subjects eat no more when empty than when full (16 versus 14 crackers), this quantity, presumably, being about the minimum necessary to complete the taste assessment.
Fat subjects, however, showed little or no response to either treatment. They ate almost exactly as much when full as when empty (18 crackers in each case), and a similar amount whether frightened or calm (20 versus 17 crackers).
To summarize, when provided with an opportunity to snack on crackers, thin subjects eat more when empty than when full, but less when manipulated into a state of fear or anxiety than when calm. However, neither fear nor fullness had a significant effect on the number of crackers snacked by fat subjects.
The information presented here is derived from a chapter about the physiological correlates of hunger in the book Emotion Obesity and Crime (1971) by the late American psychologist, Stanley Schachter.
(1) Schachter, s., R. Goldman and A. Gordon. 1968. The effect of fear, food deprivation, and obesity on eating. J. Personality and Social Psychology. 10: 91-97.