The impact of a poverty reduction intervention on infant brain activity.

Early childhood poverty is a risk factor for lower school achievement, reduced earnings, and poorer health, and has been associated with differences in brain structure and function. Whether poverty causes differences in neurodevelopment, or is merely associated with factors that cause such differences, remains unclear. Here, we report estimates of the causal impact of a poverty reduction intervention on brain activity in the first year of life. We draw data from a subsample of the Baby's First Years study, which recruited 1,000 diverse low-income mother-infant dyads. Shortly after giving birth, mothers were randomized to receive either a large or nominal monthly unconditional cash gift. Infant brain activity was assessed at approximately 1 y of age in the child's home, using resting electroencephalography (EEG; n = 435). We hypothesized that infants in the high-cash gift group would have greater EEG power in the mid- to high-frequency bands and reduced power in a low-frequency band compared with infants in the low-cash gift group. Indeed, infants in the high-cash gift group showed more power in high-frequency bands. Effect sizes were similar in magnitude to many scalable education interventions, although the significance of estimates varied with the analytic specification. In sum, using a rigorous randomized design, we provide evidence that giving monthly unconditional cash transfers to mothers experiencing poverty in the first year of their children's lives may change infant brain activity. Such changes reflect neuroplasticity and environmental adaptation and display a pattern that has been associated with the development of subsequent cognitive skills.

Delay of gratification and adult outcomes: The Marshmallow Test does not reliably predict adult functioning.

This study extends the analytic approach conducted by Watts et al. (2018) to examine the long-term predictive validity of delay of gratification. Participants (n = 702; 83% White, 46% male) completed the Marshmallow Test at 54 months (1995-1996) and survey measures at age 26 (2017-2018). Using a preregistered analysis, Marshmallow Test performance was not strongly predictive of adult achievement, health, or behavior. Although modest bivariate associations were detected with educational attainment (r = .17) and body mass index (r = -.17), almost all regression-adjusted coefficients were nonsignificant. No clear pattern of moderation was detected between delay of gratification and either socioeconomic status or sex. Results indicate that Marshmallow Test performance does not reliably predict adult outcomes. The predictive and construct validity of the ability to delay of gratification are discussed.

Effects of homicide timing on test scores: Quasi-experimental evidence from two cities in Colombia.

This study examines the effect of homicides around schools on the standardized test scores of fifth and ninth graders (N = 4729; Mage = 12.71 years, SDage = 2.13) using a quasi-experimental design in two Colombian cities. Exposure to homicides occurring within 7 days of the test and within 500 m of the school decreases test scores by 0.10 SD. Effects show a greater sensitivity to timing than distance, becoming null as the time to the testing date increases but remaining consistent across larger radii. Since students in the study are on average exposed to 12.1 homicides per year, even short-lived learning losses can accumulate to impair learning for substantial portions of the school year. Findings are discussed, considering previous empirical work.

Child-directed speech in a large sample of U.S. mothers with low income.

Research on early language input and socioeconomic status typically relies on correlations in small convenience samples. Using data from Baby's First Years, this paper assesses the causal impact of monthly, unconditional cash transfers on child-directed speech and child vocalizations among a large, racially diverse sample of low-income U.S. mothers and their 1-year-olds (N = 563; 48% girls; 2019-2020). The monthly, unconditional cash transfers did not impact mothers' child-directed speech during a 10-min at-home play session (effect sizes range from -.08 to .02), though there was wide variability within this sample. Future work will assess the impact of the continued cash transfer on children's language input and development over time.

EVALUATING CONTRADICTORY EXPERIMENTAL AND NON-EXPERIMENTAL ESTIMATES OF NEIGHBORHOOD EFFECTS ON ECONOMIC OUTCOMES FOR ADULTS.

Although non-experimental studies find robust neighborhood effects on adults, such findings have been challenged by results from the Moving to Opportunity (MTO) residential mobility experiment. Using a within-study comparison design, this paper compares experimental and non-experimental estimates from MTO and a parallel analysis of the Panel Study of Income Dynamics (PSID). Striking similarities were found between non-experimental estimates based on MTO and PSID. No clear evidence was found that different estimates are related to duration of adult exposure to disadvantaged neighborhoods, non-linear effects of neighborhood conditions, magnitude of the change in neighborhood context, frequency of moves, treatment effect heterogeneity, or measurement, although uncertainty bands around our estimates were sometimes large. One other possibility is that MTO-induced moves might have been unusually disruptive, but results are inconsistent for that hypothesis. Taken together, the findings suggest that selection bias might account for evidence of neighborhood effects on adult economic outcomes in non-experimental studies.

Unconditional cash transfers and maternal substance use: findings from a randomized control trial of low-income mothers with infants in the U.S.

BACKGROUND: Policy debates over anti-poverty programs are often marked by pernicious stereotypes suggesting that direct cash transfers to people residing in poverty encourage health-risking behaviors such as smoking, drinking, and other substance use. Causal evidence on this issue is limited in the U.S. Given the prominent role of child allowances and other forms of cash assistance in the 2021 American Rescue Plan and proposed Build Back Better legislation, evidence on the extent to which a monthly unconditional cash gift changes substance use patterns among low-income mothers with infants warrants attention, particularly in the context of economic supports that can help improve early environments of children. METHOD: We employ a multi-site, parallel-group, randomized control trial in which 1,000 low-income mothers in the U.S. with newborns were recruited from hospitals shortly after the infant's birth and randomly assigned to receive either a substantial ($333) or a nominal ($20) monthly cash gift during the early years of the infant's life. We estimate the effect of the unconditional cash transfer on self-report measures of maternal substance use (i.e., alcohol, cigarette, or opioid use) and household expenditures on alcohol and cigarettes after one year of cash gifts. RESULTS: The cash gift difference of $313 per month had small and statistically nonsignificant impacts on group differences in maternal reports of substance use and household expenditures on alcohol or cigarettes. Effect sizes ranged between - 0.067 standard deviations and + 0.072 standard deviations. The estimated share of the $313 group difference spent on alcohol and tobacco was less than 1%. CONCLUSIONS: Our randomized control trial of monthly cash gifts to mothers with newborn infants finds that a cash gift difference of $313 per month did not significantly change maternal use of alcohol, cigarettes, or opioids or household expenditures on alcohol or cigarettes. Although the structure of our cash gifts differs somewhat from that of a government-provided child allowance, our null effect findings suggest that unconditional cash transfers aimed at families living in poverty are unlikely to induce large changes in substance use and expenditures by recipients. TRIAL REGISTRATION: Registered on Clinical Trials.gov NCT03593356 in July of 2018.

Chronic Demyelination and Axonal Degeneration in Multiple Sclerosis: Pathogenesis and Therapeutic Implications.

PURPOSE OF REVIEW: Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system (CNS). Inflammatory attacks in MS lead to both demyelination and axonal damage. However, due to incomplete remyelination most MS lesions remain chronically demyelinated. In parallel, there is axonal degeneration in the CNS of MS patients, contributing to progressive disability. There are currently no approved therapies that adequately restore myelin or protect axons from degeneration. In this review, we will discuss the pathophysiology of axonal loss and chronic demyelination in MS and how understanding this pathophysiology is leading to the development of new MS therapeutics. RECENT FINDINGS: Ongoing research into the function of oligodendrocytes and myelin has revealed the importance of their relationship with neuronal health. Demyelination in MS leads to a number of pathophysiologic changes contributing to axonal generation. Among these are mitochondrial dysfunction, persistent neuroinflammation, and the effects of reactive oxygen and nitrogen species. With this information, we review currently approved and investigational therapies designed to restore lost or damaged myelin and protect against neuronal degeneration. The development of therapies to restore lost myelin and protect neurons is a promising avenue of investigation for the benefit of patients with MS.

The fate and function of oligodendrocyte progenitor cells after traumatic spinal cord injury.

Oligodendrocyte progenitor cells (OPCs) are the most proliferative and dispersed population of progenitor cells in the adult central nervous system, which allows these cells to rapidly respond to damage. Oligodendrocytes and myelin are lost after traumatic spinal cord injury (SCI), compromising efficient conduction and, potentially, the long-term health of axons. In response, OPCs proliferate and then differentiate into new oligodendrocytes and Schwann cells to remyelinate axons. This culminates in highly efficient remyelination following experimental SCI in which nearly all intact demyelinated axons are remyelinated in rodent models. However, myelin regeneration comprises only one role of OPCs following SCI. OPCs contribute to scar formation after SCI and restrict the regeneration of injured axons. Moreover, OPCs alter their gene expression following demyelination, express cytokines and perpetuate the immune response. Here, we review the functional contribution of myelin regeneration and other recently uncovered roles of OPCs and their progeny to repair following SCI.

The Kindergarten Early Development Instrument Predicts Third Grade Academic Proficiency.

School readiness skills predict later educational achievement, health, and social-emotional outcomes. Measures of school readiness can provide valuable information to assess both the impact of strategies and policies that prepare children for school as well as informing strategies for improving children's educational trajectories across their school years. The Early Development Instrument (EDI) is a measure of school readiness skills based on teacher-reported observational recall. It has been used extensively in Canada and Australia and is in the early stages of adoption in a number of U.S. cities. The current study uses data from roughly 3,000 children followed longitudinally from kindergarten through third grade from 7 school districts in Orange County, California. The study assesses whether EDI ratings in kindergarten predict third grade proficiency in mathematics and English Language Arts on state assessments. Ratings on the EDI were strongly associated with proficiency in both academic areas, even in the presence of controls for child-level factors and neighborhood fixed effects. Among its components, ratings on the language and cognitive development, communication skills and general knowledge, and social competence domains strongly differentiated children's likelihood of later proficiency in both academic areas. Implications for improving comprehensive early childhood education and schooling policies based on indicators of school readiness are discussed.

The Roles of Transfer of Learning and Forgetting in the Persistence and Fadeout of Early Childhood Mathematics Interventions.

Although many interventions have generated immediate positive effects on mathematics achievement, these effects often diminish over time, leading to the important question of what causes fadeout and persistence of intervention effects. This study investigates how children's forgetting contributes to fadeout and how transfer contributes to the persistence of effects of early childhood mathematics interventions. We also test whether having a sustaining classroom environment following an intervention helps mitigate forgetting and promotes new learning. Students who received the intervention we studied forgot more in the following year than students who did not, but forgetting accounted for only about one-quarter of the fadeout effect. An offsetting but small and statistically non-significant transfer effect accounted for some of the persistence of the intervention effect - approximately one-tenth of the end-of-program treatment effect and a quarter of the treatment effect one year later. These findings suggest that most of the fadeout was attributable to control-group students catching up to the treatment-group students in the year following the intervention. Finding ways to facilitate more transfer of learning in subsequent schooling could improve the persistence of early intervention effects.

Myelinogenic Plasticity of Oligodendrocyte Precursor Cells following Spinal Cord Contusion Injury.

Spontaneous remyelination occurs after spinal cord injury (SCI), but the extent of myelin repair and identity of the cells responsible remain incompletely understood and contentious. We assessed the cellular origin of new myelin by fate mapping platelet-derived growth factor receptor α (PDGFRα), Olig2+, and P0+ cells following contusion SCI in mice. Oligodendrocyte precursor cells (OPCs; PDGFRα+) produced oligodendrocytes responsible for de novo ensheathment of ∼30% of myelinated spinal axons at injury epicenter 3 months after SCI, demonstrating that these resident cells are a major contributor to oligodendrocyte regeneration. OPCs also produced the majority of myelinating Schwann cells in the injured spinal cord; invasion of peripheral myelinating (P0+) Schwann cells made only a limited contribution. These findings reveal that PDGFRα+ cells perform diverse roles in CNS repair, as multipotential progenitors that generate both classes of myelinating cells. This endogenous repair might be exploited as a therapeutic target for CNS trauma and disease.SIGNIFICANCE STATEMENT Spinal cord injury (SCI) leads to profound functional deficits, though substantial numbers of axons often survive. One possible explanation for these deficits is loss of myelin, creating conduction block at the site of injury. SCI leads to oligodendrocyte death and demyelination, and clinical trials have tested glial transplants to promote myelin repair. However, the degree and duration of myelin loss, and the extent and mechanisms of endogenous repair, have been contentious issues. Here, we use genetic fate mapping to demonstrate that spontaneous myelin repair by endogenous oligodendrocyte precursors is much more robust than previously recognized. These findings are relevant to many types of CNS pathology, raising the possibility that CNS precursors could be manipulated to repair myelin in lieu of glial transplantation.

Revisiting the Marshmallow Test: A Conceptual Replication Investigating Links Between Early Delay of Gratification and Later Outcomes.

We replicated and extended Shoda, Mischel, and Peake's (1990) famous marshmallow study, which showed strong bivariate correlations between a child's ability to delay gratification just before entering school and both adolescent achievement and socioemotional behaviors. Concentrating on children whose mothers had not completed college, we found that an additional minute waited at age 4 predicted a gain of approximately one tenth of a standard deviation in achievement at age 15. But this bivariate correlation was only half the size of those reported in the original studies and was reduced by two thirds in the presence of controls for family background, early cognitive ability, and the home environment. Most of the variation in adolescent achievement came from being able to wait at least 20 s. Associations between delay time and measures of behavioral outcomes at age 15 were much smaller and rarely statistically significant.

Moving Beyond Correlations in Assessing the Consequences of Poverty.

In the United States, does growing up in a poor household cause negative developmental outcomes for children? Hundreds of studies have documented statistical associations between family income in childhood and a host of outcomes in childhood, adolescence, and adulthood. Many of these studies have used correlational evidence to draw policy conclusions regarding the benefits of added family income for children, in particular children in families with incomes below the poverty line. Are these conclusions warranted? After a review of possible mechanisms linking poverty to negative childhood outcomes, we summarize the evidence for income's effects on children, paying particular attention to the strength of the evidence and the timing of economic deprivation. We demonstrate that, in contrast to the nearly universal associations between poverty and children's outcomes in the correlational literature, impacts estimated from social experiments and quasi-experiments are more selective. In particular, these stronger studies have linked increases in family income to increased school achievement in middle childhood and to greater educational attainment in adolescence and early adulthood. There is no experimental or quasi-experimental evidence in the United States that links child outcomes to economic deprivation in the first several years of life. Understanding the nature of socioeconomic influences, as well as their potential use in evidence-based policy recommendations, requires greater attention to identifying causal effects.

What Is the Long-Run Impact of Learning Mathematics During Preschool?

The current study estimated the causal links between preschool mathematics learning and late elementary school mathematics achievement using variation in treatment assignment to an early mathematics intervention as an instrument for preschool mathematics change. Estimates indicate (n = 410) that a standard deviation of intervention-produced change at age 4 is associated with a 0.24-SD gain in achievement in late elementary school. This impact is approximately half the size of the association produced by correlational models relating later achievement to preschool math change, and is approximately 35% smaller than the effect reported by highly controlled ordinary least squares (OLS) regression models (Claessens et al., 2009; Watts et al., ) using national data sets. Implications for developmental theory and practice are discussed.

Maternal Age and Child Development.

Although the consequences of teen births for both mothers and children have been studied for decades, few studies have taken a broader look at the potential payoffs-and drawbacks-of being born to older mothers. A broader examination is important given the growing gap in maternal ages at birth for children born to mothers with low and high socioeconomic status. Drawing data from the Children of the NLSY79, our examination of this topic distinguishes between the value for children of being born to a mother who delayed her first birth and the value of the additional years between her first birth and the birth of the child whose achievements and behaviors at ages 10-13 are under study. We find that each year the mother delays a first birth is associated with a 0.02 to 0.04 standard deviation increase in school achievement and a similar-sized reduction in behavior problems. Coefficients are generally as large for additional years between the first and given birth. Results are fairly robust to the inclusion of cousin and sibling fixed effects, which attempt to address some omitted variable concerns. Our mediational analyses show that the primary pathway by which delaying first births benefits children is by enabling mothers to complete more years of schooling.

Neighborhood effects on use of African-American Vernacular English.

African-American Vernacular English (AAVE) is systematic, rooted in history, and important as an identity marker and expressive resource for its speakers. In these respects, it resembles other vernacular or nonstandard varieties, like Cockney or Appalachian English. But like them, AAVE can trigger discrimination in the workplace, housing market, and schools. Understanding what shapes the relative use of AAVE vs. Standard American English (SAE) is important for policy and scientific reasons. This work presents, to our knowledge, the first experimental estimates of the effects of moving into lower-poverty neighborhoods on AAVE use. We use data on non-Hispanic African-American youth (n = 629) from a large-scale, randomized residential mobility experiment called Moving to Opportunity (MTO), which enrolled a sample of mostly minority families originally living in distressed public housing. Audio recordings of the youth were transcribed and coded for the use of five grammatical and five phonological AAVE features to construct a measure of the proportion of possible instances, or tokens, in which speakers use AAVE rather than SAE speech features. Random assignment to receive a housing voucher to move into a lower-poverty area (the intention-to-treat effect) led youth to live in neighborhoods (census tracts) with an 11 percentage point lower poverty rate on average over the next 10-15 y and reduced the share of AAVE tokens by ∼3 percentage points compared with the MTO control group youth. The MTO effect on AAVE use equals approximately half of the difference in AAVE frequency observed between youth whose parents have a high school diploma and those whose parents do not.

Parental Income and Children's Life Course: Lessons from the Panel Study of Income Dynamics.

This article reviews how the Panel Study of Income Dynamics (PSID) has contributed to our understanding of the links between childhood economic conditions- in particular, the household incomes with very young children-and the economic attainment and health of those children when they reach adulthood. From its beginning, the PSID has provided data useful for addressing intergenerational questions. In the mid-1990s, PSID data supported a series of studies that link early childhood income to early adult attainments, particularly to completed schooling. At the same time, discoveries in neurobiology and epidemiology were beginning to provide details on the processes producing the observed correlations. These discoveries led to a more recent set of PSID-based studies that focus not only on labor market and behavioral outcomes, but also on links between income in the earliest stages of life (including the prenatal period) and adult health. Links between economic disadvantage in childhood and adult health, and the developmental neuroscience underlying those links, are promising areas for future research.

Boosting School Readiness: Should Preschool Teachers Target Skills or the Whole Child?

We use experimental data to estimate impacts on school readiness of different kinds of preschool curricula - a largely neglected preschool input and measure of preschool quality. We find that the widely-used "whole-child" curricula found in most Head Start and pre-K classrooms produced higher classroom process quality than did locally-developed curricula, but failed to improve children's school readiness. A curriculum focused on building mathematics skills increased both classroom math activities and children's math achievement relative to the whole-child curricula. Similarly, curricula focused on literacy skills increased literacy achievement relative to whole-child curricula, despite failing to boost measured classroom process quality.