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Poverty has a detrimental effect on children’s development and is associated with deficits in memory and learning, cognitive control, and emotional processing. Chronic poverty is especially damaging because the neurological and cognitive deficits accumulate over childhood.

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Forty-five percent of U.S. children under 3 years of age (including two thirds of Black, Hispanic, and Native American children) live in low-income families (income less than $48,000 per year for a family of four), and 23% live in poor families (income less than $24,000) (Koball & Jiang, 2018) (see Table 5.8). In 2013, the American Academy of Pediatrics added child poverty to its Agenda for Children in recognition of poverty’s broad and enduring effects on child health and development (American Academy of Pediatrics, 2017). Infants and children from poor families experience higher rates of malnutrition, growth stunting, and susceptibility to illness than do their peers (Yoshikawa, Aber, & Beardslee, 2012).

Exposure to chronic long-term poverty has negative effects on brain growth and is associated with lower volumes in parts of the brain associated with memory and learning, cognitive control, and emotional processing (Johnson, Riis, & Noble, 2016; Ursache & Noble, 2016). For example, a longitudinal study of 77 children from birth to age 4 revealed a link between poverty and lower gray matter volume especially in the frontal and parietal regions associated with executive function (Hanson et al., 2013). In another study, 5-week-old infants in low socioeconomic status (SES) homes tended to have smaller brain volumes than other infants, suggesting that poverty may influence biological and cognitive development during the first few weeks of life or earlier (Betancourt et al., 2016).

The effects of socioeconomic status on development vary. SES is more closely related with brain structure and cognition in children from poor homes than high SES homes (Hair, Hanson, Wolfe, Pollak, & Knight, 2015; Noble et al., 2015). That is, the detrimental effect of low SES contexts is a greater influence on children’s development than the positive effect of high SES contexts. Chronic poverty is especially damaging because the neurological and cognitive deficits accumulate over childhood (Dickerson & Popli, 2016). One way in which poverty affects development is through the quality of parent–infant interactions and infants’ exposure to language (Hackman, Gallop, Evans, & Farah, 2015). Infants in higher SES homes are talked to more and the speech they hear is often more stimulating and supportive of language development than is the case in lower SES homes (Fernald, Marchman, & Weisleder, 2013; Sheridan, Sarsour, Jutte, D’Esposito, & Boyce, 2012).

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Figure 5.8 Percentage of Children in Low-Income and Poor Families by Race/Ethnicity, 2016

Source: Koball & Jiang (2018).

Poverty is also thought to affect children’s outcomes indirectly by contributing to household chaos, a combination of household instability and disorder (Berry et al., 2016). Children reared in economic uncertainty are more likely to experience disruptions in home settings and relationships through household moves and adults moving in and out of the home (Pascoe, Wood, Duffee, & Kuo, 2016). Impoverished environments often include household crowding, lack of structure, and excessive ambient noise in the home or neighborhood (Evans & Kim, 2013). Infants and children reared in environments of household chaos may be overwhelmed by stimulation combined with little developmentally appropriate support with negative effects for cognitive development. The effects of a chaotic home environment begin early. For example, a chaotic environment has been shown to negatively affect visual processing speed for complex stimuli in 5.5-month-old infants (Tomalski et al., 2017). Poverty has early effects on children’s brain development that increase over time with lifelong implications for cognitive and language development.