How does classroom background noise affect inner speech development in children?

Inner speech (IS) refers to the internal language that individuals experience in their minds, often described as a form of self-directed verbal thinking or a conversation with oneself (Fernyhough, 2010). Recent insights emphasize that inner speech plays a functional role in cognition and executive function (Alderson-Day & Fernyhough, 2015), such as planning (Wallace et al., 2017), behavioural regulation (Dolcos & Albarracin, 2014) and emotional regulation (Fossa et al., 2020). These cognitive functions, mediated by IS, have been linked to positive educational attainment and cognitive development (Lövdén et al., 2020). So far much of the research focusing on IS, has been investigated in adult populations. This PhD project will expand the field into the development of IS in children.

Inner speech enhances cognition by transforming complex sensory information into abstract symbolic representations, making cognitive processes operations more efficient and flexible (Alderson-Day & Fernyhough, 2015). Previous studies have examined inner speech within children aged 5-7 years old (Doebel & Munakata, 2017, Manfra, 2006) showing the children presented with clear inner speech abilities. Poulton (1977) established that irrelevant noise can disrupt inner speech and therefore negatively impact children's cognitive development across these domains. Furthermore, both internal and external classroom noise have a negative effect on verbal and non-verbal cognitive tasks and academic performance in children (Shield & Dockrell, 2008, Klatte et al., 2013).

Children with hearing loss are falling behind both in academic performance and cognitive development in general (Khairi Md Daud et al., 2010). Children with hearing loss are particularly vulnerable to the negative effects of classroom noise (Crandell, 1993) and struggle to recognise speech in a noisy environment, even when wearing hearing aids, compared to typically developing children (Stewart et al., 2022). Therefore, the...