Abstract
Reading stories at bedtime was made contingent upon nonthumbsucking for girls 3, 6, and 8 yr old. According to their mothers, all had been persistent thumbsuckers since infancy. Two had accompanying dental disorders. During baseline conditions, continuous noncontingent reading occurred. During experimental conditions, reading terminated on each occasion thumbsucking was observed and resumed immediately when thumbsucking ceased. High percentages of thumbsucking occurred during baseline conditions when reading was noncontingent, and low percentages occurred during experimental conditions when reading was contingent. Bedtime thumbsucking was eliminated for all three girls.