Procedure. Tim was observed in two settings,
sitting in the lap of his physical therapist
and alone in his crib. Observations occurred
daily at 9:30 a.m. for approximately 5
min for 3 weeks and involved a 10-s partialinterval
recording system.
If his thumb simultaneously
touched two lips, a sucking interval
was recorded.
During baseline sessions,
all surgical cloth was removed from his visual
range. During testing sessions, a surgical
cloth was placed either in his lap or in his
crib depending on the condition.