To date only a few
To date, only a few studies have evaluated SES-related disparities in neural mechanisms of selective attention in children. All these studies revealed neurophysiological differences in children from lower compared to higher SES backgrounds (D’Angiulli et al., 2008; Kishiyama et al., 2009; Stevens et al., 2009). In one study (D’Angiulli et al., 2008), pre-adolescents (12–13 years) from lower and higher SES backgrounds completed a pure-tone selective attention task while event-related order cycloheximide solubility potentials (ERPs) were recorded. Although both groups exhibited comparable accuracy and reaction times, the children from lower SES backgrounds did not exhibit the expected attention effect, indexed by larger early ERP responses to the attended compared to the unattended condition. Another study of slightly younger children (7–12 years) from lower and higher SES backgrounds evaluated neural processes for attention during a visual oddball task with novel stimuli (Kishiyama et al., 2009). Similar to findings by D’Angiulli et al. (2008), behavioral accuracy and reaction times were comparable between the two groups. However, children from lower SES backgrounds exhibited reduced amplitudes for early ERP components (P1, N1, N2) elicited by rare and novel stimuli, which are thought to reflect modulation of attention, compared to peers from higher SES backgrounds (Kishiyama et al., 2009). A third study (Stevens et al., 2009) evaluated selective attention in younger children, aged 3–8 years (mean age: 6 years), from lower and higher SES backgrounds using the same child-friendly dichotic listening task employed in the current study. Children heard two stories presented simultaneously but from separate speakers located to the left and right of the participant. Children were instructed to attend to one story and ignore the other. ERPs were compared to identical physical stimuli (probes) embedded in stories when attended versus unattended. The difference in neural responses to probes in the attended versus unattended story indexed the effects of selective attention on neural processing. While children from higher SES backgrounds showed robust effects of selective attention on neural processing, these attention effects were markedly smaller in children from lower SES backgrounds. Further, these group differences were specific to distractor suppression, with children from lower SES backgrounds less able to suppress the response to probe sounds in the ignored channel than their higher SES peers. Although these previous studies suggest that SES-related disparities in neural processes for attention are evident in childhood, several questions remain. First, the previous studies were conducted either with older children/adolescents or children across a relatively broad age range. Given that brain structure, function, and attention skills undergo significant development during the preschool-age years (e.g., Bates et al., 2003; Huttenlocher and Dabholkar, 1997; Posner and Rothbart, 2007; Sanders et al., 2006), it is critical to evaluate neural systems for attention within a narrow age range. This will allow for clearer delineation of neural processes during this critical period of neurodevelopment. Second, although we know that neural systems for attention differ as a function of SES background, it is unclear whether differences reflect a developmental delay or a divergence from developmental patterns observed in children from higher SES backgrounds, which requires a longitudinal design to assess. Elucidating these differences is relevant not only to our basic understanding of disparities related to SES, but may also have relevance for the timing or nature of interventions targeting attention skills. The current study aimed to address these questions by characterizing the development of neural processes for selective attention in young children from lower SES backgrounds. Focused on the narrow range of preschool-age children (3–5 years), neural systems for selective attention were compared between children from lower versus higher SES backgrounds using the same child-friendly dichotic listening task as Stevens et al., (2009. In addition, children from lower SES backgrounds were followed longitudinally for one year in order to trace developmental changes during the critical preschool-age time period. As suggested by previous research with this age group (Karns et al., 2015; Sanders et al., 2006), we expected an attention effect in the 4-year-olds from higher SES backgrounds. Furthermore, based on previous findings in preschool-age children from lower SES backgrounds (Isbell et al., 2016a; Neville et al., 2013), we hypothesized that 4-year-old children from lower SES backgrounds would not show a significant attention effect. We also hypothesized that group differences would be specific to deficits in distractor suppression in the children from lower SES backgrounds, as suggested by previous research (Stevens et al., 2009). For the longitudinal component of the study, in which the children from lower SES backgrounds were followed for one year, we hypothesized that the effects of selective attention on neural processes would either be absent or small but emerging at age five. We based this prediction on prior literature showing protracted development of neural processes for selective attention into adolescence (Karns et al., 2015) as well as research demonstrating that slightly older children from lower SES backgrounds exhibit a significant attention effect, albeit smaller than that observed in their age-matched peers from higher SES backgrounds (Stevens et al., 2009). Importantly, these findings will enhance our understanding of the vulnerability in and development of selective attention in young children from lower SES backgrounds.