This study examines the effects of a "transitional object" (surgical cloth)
on the thumb sucking of a 3-year-old boy in two conditions: while sitting
in the lap of his physical therapist and while alone in his crib. Sucking o
ccurred when the cloth was present and did not occur when it was absent, re
gardless of condition. These results are discussed in terms of establishing
operations, object attachment, and application.