Sibling thumb sucking. Effects of treatment for targeted and untargeted siblings.
Taking a shared comfort object from one child cut thumb-sucking in both sisters through social contagion.
01Research in Context
What this study did
Watson et al. (2002) worked with two young sisters who both sucked their thumbs while holding the same pillow.
They first took the pillow away from the older girl only. Then they gave it back. Then they took it away again.
They counted thumb-sucking in both girls across all phases.
What they found
When the pillow left the older girl’s bed, thumb-sucking dropped in both sisters.
When the pillow returned, both girls started sucking again.
The untreated little sister changed her behavior simply by watching her big sister lose the object.
How this fits with other research
Friman (2000) first showed the same thing in one boy: no cloth, no thumb-sucking. Steuart extends that idea to siblings and adds a return phase.
Storch et al. (2012) tried adult control of stereotypy objects with mixed results. Their data remind us that simply removing an item may not work for every child.
Leon et al. (2013) paired extinction with FCT for ritual behavior. Steuart used extinction alone, but both teams saw large drops in problem behavior.
Why it matters
You can shrink thumb-sucking without treating every child in the house. Remove the cued object from the leader sibling and watch the follower copy the change. Track both kids to be sure the effect holds, and plan for the day you give the object back.
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02At a glance
03Original abstract
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.
Behavior modification, 2002 · doi:10.1177/0145445502026003007