Treatment of unobserved trichotillomania by attention-reflection and punishment of an apparent covariant.

Frequent but primarily unobserved hairpulling, by a 3-yr-old girl was followed by a differential reinforcement procedure, attention-reflection, and punishment of thumbsucking, a possibly covarying behavior. Initially, attention-reflection reduced the hairpulling, but not to a clinically significant level. Dramatic decreases in hairpulling were achieved when thumbsucking was punished by application of a "bad tasting" substance. A brief reversal supports the contention that the two behaviors were correlated and suggests that behaviors may be controlled by targeting observable covariants.