What reinforces in a social reinforcement situation words or expressions?

Compares changes in preference and response rate in a study using 96 5-9 yr. old Ss for 3 conditions: verbal reinforcement, E present but silent, and the E removed from the immediate situation. Increases in rate of responding were greatest in the reinforcement conditions, but the increases occurred before reinforcement was initiated. Rate increases seemed to be a consequence of changes in S's emotional state, which were related to the E's treatment of the child. Preference shifts occur regardless of reinforcement as long as the E remained. E's expressive behavior appeared to cause such shifts. Although expressive communication plays an important role in changing task behavior, its effectiveness may depend upon S and E sharing particular conceptions of the teacher's and learner's role in the task. (17 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved).