Cardiac self-perception in obese and normal persons.

Cardiac self-perception was measured in obese and normal weight subjects. Subjects had to judge whether a tone was coincident with their own heartbeat or slightly mismatched. A signal-detection analysis was used to measure sensory sensitivity to the heartbeat separate from nonsensory, response-bias factors. Subjects were able to perform the heartbeat-detection task, with an average sensory sensitivity d' of .58. No significant differences in sensory sensitivity were found between obese and normal-weight subjects, nor were any sex differences noted. Measurement of response bias (Ln beta) indicated that obese subjects had a significantly more lax response criterion than normal-weight subjects. Results are discussed in terms of Schachter's (1971) internality-externality theory of obesity and ramifications for weight control are discussed.