| Popis: |
‘Executive function’ (EF) is an umbrella term that encompasses the processes responsible for purposeful, goal-directed behaviour (Anderson, 2002; Diamond & Lee, 2011). In this study we examine the two core components of executive function that have been identified in children (Lee et al., 2013; St Clair-Thompson & Gathercole, 2004): (1) Working Memory (WM), a limited capacity system that allows the storage and manipulation of information over short time periods (Baddeley, 2010; Cowan, 2017), sometimes referred to as updating in the EF literature (2) Inhibition, which can be defined as the ability to deliberately inhibit dominant or automatic responses (Aron, 2007) We are also looking at processing speed, which relates to the speed of information processing and is normally measured using a simple reaction-time task (Coyle et al., 2011). It is well established that higher childhood socioeconomic status (SES) is associated with both higher scores on tasks of different executive functions (Lawson et al., 2018; Mooney et al., 2021, 2022), and better levels of academic attainment in childhood (Sirin, 2005; Waters et al., 2021). Higher scores on EF tasks are also associated with better academic attainment (Coyle et al., 2011; Gathercole et al., 2003; Mulder et al., 2010; St Clair-Thompson & Gathercole, 2006). More recently, some longitudinal studies have looked at whether executive functions mediate the association between SES and academic attainment. However, several of these studies used a composite measure of EF, combining tasks that measure different elements of EF, test whether the association between SES and academic attainment is mediated by ‘global’ EF (Deer et al., 2020; Ellefson et al., 2020; Lawson & Farah, 2017; Nesbitt et al., 2013). For example, Ellefson et al (2020) and Lawson & Farah (2017) found that global EF mediated the association between SES and numeracy or maths, and Nesbitt et al (2013) found that global EF mediated the association between SES and broader educational attainment. Whilst it is important to establish that EFs are mediating this association, this does not establish which of the EFs may be most important in this relationship. Only three studies have looked within different EF components to find which may be the most important mediator. In a relatively small sample of 203 children (aged 9–13 years), Albert et al (2020) found that verbal WM was the only EF measure that mediated the association between SES and both reading and maths achievement at 7th grade. Similarly, Poon et al (2022) found that WM and cognitive flexibility, but not inhibition, mediated the association between SES and a teacher report of educational attainment in a sample of 385 children aged 8 years old. Finally, in a larger study (N=1273) of infants and young children (aged 1-54 months), Waters et al (2021) found that WM was the only EF that mediated the association between SES and two subtests of the Woodcock Johnson tests of achievement battery. Therefore, when separating out different EF components, the limited studies in this area suggest that WM is the key factor mediating the relationship between SES and academic attainment. However, only one of these three studies used a measure that reflected children’s actual academic attainment on a nationally administered test (Albert et al, 2020), with the others using teacher reports (Poon et al., 2022) or the Woodcock Johnson test (Waters et al., 2021). Whilst associations between SES and tests such as the Woodcock Johnson are informative, it is important to look at the impact of SES and EF on children’s performance on nationally administered tests (e.g., Key Stage tests, A Levels). It is nationally administered tests which predicts a child’s life outcomes terms of their socioeconomic mobility (Breen & Karlson, 2014), as a child’s attainment at GCSE or A-Level determines their future chances of obtaining further qualifications in higher education, or for obtaining future employment. It is therefore important to use these types of tests as the outcome variable to fully understand how different aspects of EF mediate the relationship between SES and academic outcomes. Further, the majority of these studies lack ethnic diversity in their samples (e.g. the Deer et al., 2020 sample was 96% White). We have previously found ethnic group variation in tasks of WM in BiB (Mooney et al, 2021). It is therefore possible that the associations between SES, EF, and attainment may vary within different ethnic groups. There are fewer studies that have linked childhood SES to childhood processing speed ability. A study of 121 children aged 4-5 years tested the association between SES, EF (working memory and inhibitory control), and a proxy measure of processing speed (reaction times to the EF tasks) (St. John et al., 2019). They found that SES was related to both working memory and inhibitory control, as well as to working memory reaction times (proxy PS measure). In a study of 166 children aged 7-11, Buckhalt et al., (2007) examined whether ethnicity and SES moderated the link between children’s sleep and cognitive functioning (including processing speed), and found direct associations between SES and a standard measure of processing speed (measured via a visual matching task from Woodcock Johnson III). Several studies have directly linked processing speed to educational attainment, with some demonstrating it has distinct associations with children’s attainment that are separable from the influence that WM has with attainment (Davies et al., 2016; Mulder et al., 2010; Passolunghi & Lanfranchi, 2012). Further, Gordon et al. (2018) have proposed that processing speed within EF tasks can be used to predict academic attainment. However, in contrast to the growing body of research that examines EF as a mediator between SES and attainment, no studies have looked at whether processing speed mediates this association. In this study, we therefore test the contribution of EF versus processing speed in mediating the association between SES and children’s attainment. We also test the contribution of distinct EF’s (WM and inhibition) in mediating the association between SES and children’s attainment. |
