Sibling thumb sucking. Effects of treatment for targeted and untargeted siblings

In this study, removal of a transitional object (pillow) was applied as the sole intervention for one of two siblings who sucked their thumbs. The intervention was applied only to the older sibling, whereas data were collected on the thumb sucking of both participants. Results indicated that removal of the transitional object for the older sibling reduced thumb sucking in both siblings and increased thumb sucking when the pillow was reintroduced. Discussion focuses on possible explanations for the effects of the intervention across both participants and the limitations of this study.