Review
Socioeconomic status and the developing brain

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Childhood socioeconomic status (SES) is associated with cognitive achievement throughout life. How does SES relate to brain development, and what are the mechanisms by which SES might exert its influence? We review studies in which behavioral, electrophysiological and neuroimaging methods have been used to characterize SES disparities in neurocognitive function. These studies indicate that SES is an important predictor of neurocognitive performance, particularly of language and executive function, and that SES differences are found in neural processing even when performance levels are equal. Implications for basic cognitive neuroscience and for understanding and ameliorating the problems related to childhood poverty are discussed.

Section snippets

Why study the neuroscience of socioeconomic status?

What is socioeconomic status (SES), and why would a cognitive neuroscientist have anything to say about it? Volumes have been written about the first question, but for present purposes we will simply say that virtually all societies have better off and less well off citizens, and that differences in material wealth tend to be accompanied by noneconomic characteristics such as social prestige and education 1, 2, 3, 4, 5, 6 (Box 1). SES refers to this compound of material wealth and noneconomic

Neurocognitive performance

Although IQ tests reflect the function of the brain, they are relatively uninformative concerning the specific neurocognitive systems responsible for performance differences. Recent research has, therefore, incorporated behavioral tests that support more specific inferences. For purposes of relating task performance to underlying systems, we propose the following simple parse of brain function into five relatively independent neurocognitive systems defined anatomically based on studies of

Electrophysiological measures

To investigate SES disparities in brain development more directly, several research groups have recently turned to electrophysiological measures of neurocognitive processing. Baseline electroencephalographic (EEG) activity has been used to assess overall differences in resting brain function, and two studies have found differences in the pattern of EEG as a function of SES. In a study of Mexican preschool children, Otero and colleagues [38] found evidence consistent with a maturational lag in

Neuroimaging

For purposes of localizing differences in cognitive ability to specific, anatomically defined neural systems, magnetic resonance imaging (MRI) provides far more direct and accurate information than the most carefully chosen behavioral tasks or the densest array of scalp electrodes. Unfortunately, there are few studies of SES using functional or structural neuroimaging. Two studies have so far examined SES disparities in cognitive function with functional MRI (fMRI) in normal children and one

Manipulations of social status

The vast majority of cognitive neuroscience laboratories conduct research with participants of middle SES. The restricted range of SES in easily accessible subject populations is undoubtedly partly responsible for the neglect of SES as a variable in human brain development and function. Some researchers who are interested in the effects of social hierarchy on neurocognitive function have found a way to address the issue with middle SES subjects: they have manipulated subjects’ social status and

Mechanisms

What is the cause of SES differences in brain function? Is it contextual priming? Is it social causation, reflecting the influence of SES on brain development? Alternatively, is it social selection, in which abilities inherited from parents lead to lower SES [9]? Current research on SES and brain development is not designed to answer this question. However, research on SES and IQ is relevant and supports a substantial role of SES and its correlated experience as causal factors 1, 7, 8, 9, 10, 11

Current knowledge and future research directions

Although abundant research has documented the influence of SES on cognitive ability as measured by IQ tests and school achievement, we have only the most preliminary understanding of the specific neurocognitive effects of SES. Research to date indicates that SES disparities are most robust in language and executive functions, and perhaps also declarative memory, although they are not restricted to these functions, and much remains to be learned about the specific aspects of these functions

Acknowledgements

The writing of this article was supported by NIH grants R01-HD043078, R01-HD055689, R01-DA14129 and R01 DA0189913, as well as ONR grant N000140710034. The authors thank Kim Noble for her tremendous contributions to much of the research reviewed here and David Kraemer for assistance with figure preparation.

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