PARENTAL TRAINING OF THE PLURAL MORPHEME IN NORMAL TODDLERS1

Abstract

Experimental studies with young normal children can provide useful strategy for the functional analysis of language. Research by Whitehurst (Journal of Experimental Child Psychology, 1972, 13, 502–515) exemplifies this approach, in which 2‐yr‐old children were exposed to a training procedure that involved imitation and differential reinforcement for a two‐word productive sequence of the adjective‐noun form. Results indicated that these young children could be trained to produce rudimentary novel utterances that were grammatically appropriate. More recently, Hursh and Sherman (Journal of Experimental Child Psychology, 1973, 15, 328–339) reported the existence of a functional relationship between parental modelling and reinforcement of vocalizations, and increased instances of these vocalizations in young (15‐ to 20‐month‐old) children. These demonstrations relate to a summary of findings with linguistically deviant populations discussed by Sherman (Advances in Child Development, 1971). The present study attempts to extend these “generative” investigations to normal children and to provide useful information for those interested in teaching speech forms to them. Modelling and differential reinforcement were used by three mothers to establish the use of the plural morpheme in the speech of their 19‐ to 25‐month‐old children. During training trials, verbal praise was presented contingent on correct labelling of singular and plural items, while correct labelling was modelled if the child responded incorrectly. Children learned to label specifically trained sets of singular and plural items and also exhibited correct labelling when asked to label never‐trained singular and plural items. After establishing correct usage, the same training procedures were used to train reversed labelling (plural responses to single items and singular responses to plural items). This produced a corresponding reversal of responding (both trained and untrained items) by each child for the plural items but not for singular items. Correct singular and plural labelling was recovered by returning to the initial procedures.