Experimental Manipulation of Verbal Behavior in Defectives

Abstract

Although the empirical basis of contemporary reinforcement theory consists largely of data on infrahuman Ss, there has been a strong tendency among psychologists to extend the principles to human behavior. One of the more notable attempts has been Skinner's treatment of verbal behavior ( 5 ) . According to this view, language is a form of operant behavior, highly contingent upon reinforcement parameters. A testable implication of the position is that the regularity with which a particular word is emitted is dependent upon the history of regularity and pattern of reward. Several experiments have provided data which support this notion. Greenspoon (4 ) found that the number of plural nouns voiced ad libitum by college students could be increased through reinforcement administered by having E say Umhmm after the response. Ss subsequently indicated that they were unaware of any contingency between their behavior and that of E. Taffel ( 6 ) , using a modification of Greenspoon's procedure, had adult psychiatric patients respond to discrete stimulus presentations. S was required to form a sentence when presented with a verb and a choice of one of six personal pronouns to be used in starting the sentence. It was found that the proportion of first person pronouns used by S could be readily increased by verbal reinforcement without S's awareness of reward contingencies. A more extensive investigation presenting similar findings has recently been reported by Cohen, et al. ( 1 ) . Fleishman ( 3 ) and Zigler ( 7 ) have suggested that the effectiveness of verbal rewards in controlling human behavior may be dependent upon Ss' intellectual level. Whether or not the principle applies to the behavior of humans with low adaptive skills, i.e., mental defectives, is the concern of the present experiment. Previous research pertaining to motivational phenomena in these Ss has yielded results which are apparently inconsistent, as indicated in a recent review by Ellis and Pryer ( 2 ) . The present study, following Greenspoon, attempts to manipulate verbal behavior in defectives with verbal reinforcement. METHOD Apparatzcs.-The materials consisted of 80 3 X 5 in. white index cards.