Microgenetic change in the quantity and quality of preschoolers' private speech

Forty preschool-aged children were videotaped while carrying out paper-folding and story-sequencing tasks, during a series of three experimental sessions. During the first session, participants worked on both easy and difficult items, and in the second and third sessions they worked on familiar items (the first session difficult items, presented repeatedly) and novel items, of each task type. Participants used more private speech on difficult/novel items than on easy/familiar items, during all three sessions. Private speech production declined across sessions when participants worked on the repeated items. A greater percentage of participants' private speech preceded action when they worked on difficult/novel items, compared with easy/familiar items. On the paper-folding items, a cross-session increase occurred in the percentage of private speech that preceded action, supporting some of Vygotsky's (1934/1987, 1978) claims about the emergence of verbal planning in private speech. The potential of microgenetic experimental methodology for research on private speech is emphasised.