Verbally responsive input and language development in autistic two- and three-year olds

When parental input follows-in on a child’s focus of attention, it can effectively facilitate that child’s subsequent language acquisition (Bornstein et al., 1999; Hoff & Naigles, 2002; McCathren et al., 1995; McDuffie & Yoder, 2010; Siller & Sigman, 2002; Smith, et al., 1988). This kind of input, known as parental verbal responsiveness (PVR), provides labels for objects and actions which are immediately salient to the child (Baldwin, 1995; Tomasello & Farrar, 1986; Tomasello & Todd, 1983). It is also assumed to decrease the cognitive demands on the child, whose typical task of attention shifting is somewhat relieved (Adamson, Bakeman & Deckner, 2004; Atkinson & Shiffrin, 1971; Tomasello & Todd, 1983). This is especially pertinent where autistic children, some of whom have deficits in attention shifting, are concerned (Bruckner & Yoder, 2007; Haebig, et al., 2013; Mundy et al., 1986).

Different types of PVR have different impacts on language development. One such type is the follow-in comment, which provides lexical or grammatical information about the child’s focus without demanding a behavioural change. Imagine a child is playing with a toy car. A parental follow-in comment might say, “That’s a fast car you’ve got!”. Follow-in comments appear to predict an autistic child’s subsequent language level (Haebig et al., 2013; McDuffie & Yoder, 2010; Siller & Sigman, 2008). Follow-in directives are another key PVR type, and respond to the child’s focus by asking that

they change their behaviour. Their effectiveness is less well-understood: some findings imply directives

do facilitate acquisition, while others report that they fail, have an intermediary effect, or that their efficiency depends on their form (Akhtar, Dunham & Dunham, 1991; Haebig et al., 2013; McCathren, Yoder & Warren, 1995; McDuffie & Yoder, 2010; Siller & Sigman, 2002; Siller & Sigman, 2008). Following the example of more recent work, this study splits follow-in directives into two further functional categories: directives for language and directives for behaviour. Follow-in directives for language ask the child to make a linguistic production and appear to positively predict subsequent language development in autistic children (Haebig et al., 2013). A directive for language from our example parent could be, “What colour is your car?”. Alternatively, follow-in directives for behaviour ask a child to carry out an action, and appear ineffective in promoting linguistic acquisition in autistic children (Haebig et al., 2013). Our example parent might produce the directive for behaviour, “Push the car to mummy.”.

This work aims to clarify whether the three key types of PVR identified predict receptive and expressive language growth in autistic two- and three-year-olds. Comparisons are made between two sets of parental MCDI reporting which took place six-months apart, and entered into linear regression models alongside count measures of PVR obtained from videotaped parent-child free-play sessions (Fenson et al., 1993). These analyses reveal that follow-in comments are effective in facilitating receptive vocabulary until children reach a certain age, whereas their impact is limited overall for expressive language. Follow-in directives for language also appear to significantly predict receptive language growth, though their impact on expressive language is tempered by higher scoring on measures of autism profiling. Finally, directives for behaviour do not make a significant contribution to either receptive or expressive development, but do appear to moderate some of the negative effects a child’s autism profile would exert on receptive development were they not being received. These findings would imply that PVR is going some way to allowing autistic children to overcome the social barriers to language acquisition they face, especially where their receptive language development is concerned.

By further investigating and replicating these findings, future work might look to inform interventions aiming to develop linguistic competencies in minimally-verbal autistic children.