Self-directed speech in atypical development

If the developmental origins of speech for problem-solving/self-regulation and speech for memory are different, we might expect them not to be uniformly spared or impaired in atypical development, even if they tend to go hand-in-hand in typical development. In addition, we might expect dissociations within the problem- solving/self-regulation category: Considering that individuals with autism have problems monitoring their own mental states (Williams, 2010), we might expect speech for self-regulation to be impaired as a direct result of problems of self- awareness (see Fernyhough & Meins, 2009). Speech for problem-solving, on the other hand, would be impaired to the extent that its development relies on syntactic and pragmatic language abilities, and the experience of verbally-mediated joint problem-solving. Therefore, in future studies of self-directed speech in autism, it might be unwise to rely solely on the dual task paradigm: Recording private speech and its apparent function could also provide some valuable insights. Another reason for recording private speech is to measure its internalisation level, as in Chapter 4.

Note, though, that private speech rates cannot tell us everything we need to know. Recall that, in Chapter 4, rates of private speech were not deemed useful for comparing the extent to which two groups of children’s cognition was verbally mediated. This was because there are conflicting perspectives on what private speech frequency means, especially in middle childhood. As explained in Chapter 4, the frequency of participants’ private speech production can be taken as a measure of the extent to which cognition is verbally mediated, with more private speech indicating more typical development (Winsler, Abar, Feder, Schunn, & Rubio, 2007).

However, in middle childhood, more frequent private speech production could be viewed as a sign of immaturity in self-directed speech development, as children should by then be on a downward slope of private speech production, as it is internalised to form inner speech (Fernyhough & Meins, 2009). Given these conflicting perspectives, the frequency of private speech production is not a useful measure of the extent to which cognition is verbally mediated, but the measurement of this can be achieved with the dual task paradigm. A recommendation for future research is to analyse both the content and the internalisation level of children’s private speech in a dual task paradigm.

Thus the combination of methods—as used in Chapters 2 and 4—might prove particularly fruitful in the study of self-directed speech in atypical

development. The preceding discussion illustrates that researchers should be looking at different types of self-directed speech as though they might be separate, allowing for the possibility that different types of self-directed speech are less closely

associated in atypical development than in typical development.

Another point in relation to self-directed speech in atypical development is that it would be useful to have more details on exactly what aspects of joint activity

contribute to the development of problem-solving/self-regulatory private speech. NeoVygotskian theory (Fernyhough, 1996) and associated evidence (see Section 4.2) suggest that joint activity contributes to private speech development via the

internalisation of activity-related dialogue, and this was the basis for predicting disruption to self-directed speech development in both autism and SLI. However, the extent to which adults’ nonverbal behaviour during joint activity contributes to private speech development is not known. Berk and Winsler (1995) identify two nonverbal aspects of high-quality scaffolding that could be important for private speech development: (a) sensitive modulation of task difficulty and the amount of adult assistance, influencing the extent to which the task is kept at an appropriately challenging level for the child, and (b) contingent withdrawal of adult control and assistance as soon as the child is able to take on more responsibility. Winsler and colleagues (Winsler, Diaz, McCarthy, Atencio, & Adams Chabay, 1999), in their study of joint puzzle-solving activity, measured these aspects of nonverbal

scaffolding by recording the frequency with which mothers touched the puzzle and

the extent to which this decreased during the session. They found that children of mothers who withdrew control produced more partially-internalised private speech than their peers. Measures of maternal verbal tutoring and verbal modelling, on the other hand, were not related to children’s private speech production. This raises the possibility that private speech production is advanced by carefully structuring the child’s activity rather than by helping to create a dialogue that can be internalised. If so, we might expect little effect of receptive language impairment on private speech development in SLI, whereas the social impairments, sensory abnormalities, and restricted and repetitive behaviours found in autism, would present more of a barrier to participating in sustained well-structured activity. To summarise, the relative

importance of caregivers’ verbal and nonverbal behaviour for self-directed speech development will shape our predictions regarding patterns of self-directed speech development in atypically developing children. We would expect expressive language impairment to have an effect on the online use of language regardless of whether it is caregivers’ verbal or nonverbal behaviour that proves to be more important.

For the discovery of the crucial element of joint activity for self-directed speech development, again, a training study might be useful. An experimenter could investigate the effects of verbal and nonverbal scaffolding (compared to a control condition) on typically developing children’s subsequent private speech production during a task. This would be an important step in gaining an understanding of how private speech emerges from joint activity, and would allow us to formulate more specific hypotheses with regard to self-directed speech development in SLI and autism.