International differences in the speed of cognitive development: A systematic examination of the existence of the Simber Effect

The Simber Effect refers to the phenomenon whereby, in Arabic countries, young children have an IQ that is little different from that of Western children but that these differences increase throughout childhood culminating in a difference of around 20 points by adulthood. The true nature of this phenomenon is revealed by an examination of 125 samples from all around the globe measured with Raven's Progressive Matrices. We show that in many cases different speeds of cognitive development increase the IQ score differences between countries mostly between 4 and 9 years of age, and that these increases can in part be explained by poor environmental conditions. However, the patterns are not completely clear, either in terms of regularity or strengths. Methodological problems, in particular the cross-sectional designs of the included samples, as well as the significance of the Simber Effect for country comparisons in intelligence are discussed.

Adolescent health series: Adolescent neurocognitive development in Western and Sub-Saharan African contexts

The transitional period of adolescence has long been associated with physical, social and behavioural change. During this time, adolescents start to develop their own self-identity, make important life decisions and acquire the necessary skills to successfully transition to adulthood. More recently, advances in brain imaging technology have enabled increased understanding of structural and functional changes in the human brain during this developmental period, and how they relate to social, emotional, motivational and cognitive development. The ability to integrate these developing cognitive processes in increasingly complex social contexts is a key aspect of mature decision-making, which has implications for adolescent health, educational, economic and social outcomes. Insights from the field of developmental cognitive neuroscience could increase our understanding of this influential stage of life and thus inform potential interventions to promote adolescent health, a critical goal for global health research. Many social changes occur during adolescence and the social environment shapes both brain and cognitive development and the decisions adolescents make. Thus, it is important to study adolescent neurocognitive development in socio-cultural context. Yet, despite evidence from Western studies that socio-cultural and economic factors impact on adolescent neurocognitive development, existing studies of adolescent neurocognitive development in sub-Saharan Africa are relatively scarce. We summarise research findings from Western and sub-Saharan African contexts and highlight areas where research is lacking. Longitudinal studies from more diverse global samples will be needed to build a comprehensive model of adolescent development, that characterises both commonalities in developmental trajectories, as well as the way these can meaningfully differ between both individuals and contexts.

Towards a South African model of language-based learning disability

Background

This conceptual article is inspired by the first phase of a doctoral research project that aimed to develop and validate a bilingual language assessment test for IsiZulu-English-speaking children in grades 1, 2 and 3 with language-based learning disabilities (L-b LDs) in South Africa.

Objectives

Phase 1, systematic literature review, pretesting and formulating of a theoretical framework, with the aim to determine early indicators of L-b LDs; this is important for developing a clinical language test as it determines its constructs.

Method

Thematic analysis was used to develop the models.

Results

This article reviews the literature on indicators and definitions of L-b LD, introduces models that were developed in the study to conceptualise L-b LD and discusses implications for language test development.

Conclusion

The models provided in this article conceptualise L-b LD and identify its early indicators. The application of these models in both educational and clinical settings is proposed for differentiation of L-b LD.

Habituation and novelty detection fNIRS brain responses in 5- and 8-month-old infants: The Gambia and UK

The first 1,000 days of life are a critical window of vulnerability to exposure to socioeconomic and health challenges (i.e. poverty/undernutrition). The Brain Imaging for Global Health (BRIGHT) project has been established to deliver longitudinal measures of brain development from 0 to 24 months in UK and Gambian infants and to assess the impact of early adversity. Here results from the Habituation-Novelty Detection (HaND) functional near-infrared spectroscopy (fNIRS) task at 5 and 8 months are presented (N = 62 UK; N = 115 Gambia). In the UK cohort distinct patterns of habituation and recovery of response to novelty are seen, becoming more robust from 5 to 8 months of age. In The Gambia, an attenuated habituation response is evident: a larger number of trials are required before the response sufficiently suppresses relative to the response during the first presented trials. Furthermore, recovery of response to novelty is not evident at 5 or 8 months of age. As this longitudinal study continues in The Gambia, the parallel collection of socioeconomic, caregiving, health and nutrition data will allow us to stratify how individual trajectories of habituation and recovery of response to novelty associate with different risk factors and adaptive mechanisms in greater depth. Given the increasing interest in the use of neuroimaging methods within global neurocognitive developmental studies, this study provides a novel cross-culturally appropriate paradigm for the study of brain responses associated with attention and learning mechanisms across early development.

Do Schooling and Urban Residence Develop Cognitive Skills at the Expense of Social Responsibility? A Study of Adolescents in the Gambia, West Africa

The recent growth of schooling and urban residence represents a major change to the cultural context of child development across Africa. The aim of this article is to examine the relationship between these social changes in the Gambia and the development of both cognitive skills and behaviors viewed by participant communities as the basis for success in village life, comprising six aspects of social responsibility. We compared these skills and behaviors in a sample of 562 Gambian adolescents ( M age = 17.1 years) from 10 villages who had either attended a government primary school ( n = 207; 36.8%) or a madrasa ( n = 355; 63.2%). A total of 235 participants (41.8%) had spent a short time living in the Gambia’s major urban center (median visit duration of 4.2 months). This temporary urban residence was associated with improved performance in all six cognitive tests and a decrease in five of the six social responsibility scores, as rated by adults in the community. Government schooling was associated with improved performance in five of the six cognitive tests, but there was no consistent relationship with social responsibility ratings. Associations may result from the profiles of young Gambians who choose or who are selected to go to school or live in the city, or they may result from the effects of those environments on their behaviors and skills. In either case, the implications of our findings are that schooling values certain cognitive abilities and urban life values these cognitive abilities too but devalues social responsibility.

Can Touch Screen Tablets be Used to Assess Cognitive and Motor Skills in Early Years Primary School Children? A Cross-Cultural Study

Assessment of cognitive and motor functions is fundamental for developmental and neuropsychological profiling. Assessments are usually conducted on an individual basis, with a trained examiner, using standardized paper and pencil tests, and can take up to an hour or more to complete, depending on the nature of the test. This makes traditional standardized assessments of child development largely unsuitable for use in low-income countries. Touch screen tablets afford the opportunity to assess cognitive functions in groups of participants, with untrained administrators, with precision recording of responses, thus automating the assessment process. In turn, this enables cognitive profiling to be conducted in contexts where access to qualified examiners and standardized assessments are rarely available. As such, touch screen assessments could provide a means of assessing child development in both low- and high-income countries, which would afford cross-cultural comparisons to be made with the same assessment tool. However, before touch screen tablet assessments can be used for cognitive profiling in low-to-high-income countries they need to be shown to provide reliable and valid measures of performance. We report the development of a new touch screen tablet assessment of basic cognitive and motor functions for use with early years primary school children in low- and high-income countries. Measures of spatial intelligence, visual attention, short-term memory, working memory, manual processing speed, and manual coordination are included as well as mathematical knowledge. To investigate if this new touch screen assessment tool can be used for cross-cultural comparisons we administered it to a sample of children (N = 283) spanning standards 1–3 in a low-income country, Malawi, and a smaller sample of children (N = 70) from first year of formal schooling from a high-income country, the UK. Split-half reliability, test-retest reliability, face validity, convergent construct validity, predictive criterion validity, and concurrent criterion validity were investigated. Results demonstrate “proof of concept” that touch screen tablet technology can provide reliable and valid psychometric measures of performance in the early years, highlighting its potential to be used in cross-cultural comparisons and research.

Design and validation of assessment tests for young children in Zambia

Early childhood education has received unprecedented attention among African policymakers in recent years, recognizing that the early years form an important foundation upon which later development is anchored and noting evidence that various Early Childhood Development (ECD) indicators are predictive of future academic success. Central to the provision of quality early childhood education is assessment of developmental outcomes. But currently there is little systematic documentation of culturally appropriate child assessment instruments in Africa. We briefly review the literature on cross-cultural issues in child assessment and identify a variety of approaches to test design and adaptation. We then describe the process through which two child assessment instruments were developed in the Zambian context and empirical evidence was collected of their ecocultural and psychometric validity: the Panga Munthu Test and the Zambia Child Assessment Tool (ZamCAT). Implications are derived from these examples for future development of culturally responsive child assessment instruments in Africa.

The impoverished brain: disparities in maternal education affect the neural response to sound

Despite the prevalence of poverty worldwide, little is known about how early socioeconomic adversity affects auditory brain function. Socioeconomically disadvantaged children are underexposed to linguistically and cognitively stimulating environments and overexposed to environmental toxins, including noise pollution. This kind of sensory impoverishment, we theorize, has extensive repercussions on how the brain processes sound. To characterize how this impoverishment affects auditory brain function, we compared two groups of normal-hearing human adolescents who attended the same schools and who were matched in age, sex, and ethnicity, but differed in their maternal education level, a correlate of socioeconomic status (SES). In addition to lower literacy levels and cognitive abilities, adolescents from lower maternal education backgrounds were found to have noisier neural activity than their classmates, as reflected by greater activity in the absence of auditory stimulation. Additionally, in the lower maternal education group, the neural response to speech was more erratic over repeated stimulation, with lower fidelity to the input signal. These weaker, more variable, and noisier responses are suggestive of an inefficient auditory system. By studying SES within a neuroscientific framework, we have the potential to expand our understanding of how experience molds the brain, in addition to informing intervention research aimed at closing the achievement gap between high-SES and low-SES children.

Student motivation for learning in Ghana: Relationships with caregivers’ values toward education, attendance, and academic achievement

This study examined the role that Ghanaian caregivers’ values toward education play in shaping students’ intrinsic versus extrinsic motivation for learning, and the ways these values and motivational orientations predict school attendance and achievement. Study participants included 88 students (M = 11.63 years; 48% female) from two primary schools in peri-urban Ghana and their 68 caregivers (M = 40.02 years; 60% female). Results revealed that caregivers’ perception of education as valuable was related to more intrinsically oriented profiles of motivation and higher attendance in students. Contrary to research results from Western contexts, students whose motivation was more extrinsically oriented attended school significantly more often than their intrinsically motivated peers. Finally, although attendance positively predicted academic achievement, neither caregiver values nor student motivational profiles were directly related to achievement. These findings suggest that caregivers’ values may have important implications for students’ academic thoughts and behaviours, and may be a central target for school staff aiming to improve student outcomes. These results also highlight the need for better understanding of motivational processes―both in terms of socialization and academic outcomes―in under-represented contexts where cultural values around education differ.

Schooling and variation in the COMT gene: the devil is in the details

BACKGROUND

Schooling is considered one of the major contributors to the development of intelligence within societies and individuals. Genetic variation might modulate the impact of schooling and explain, at least partially, the presence of individual differences in classrooms.

METHOD

We studied a sample of 1,502 children (mean age = 11.7 years) from Zambia. Approximately 57% of these children were enrolled in school, and the rest were not. To quantify genetic variation, we investigated a number of common polymorphisms in the catechol-O-methyltransferase (COMT) gene that controls the production of the protein thought to account for >60% of the dopamine degradation in the prefrontal cortex.

RESULTS

Haplotype analyses generated results ranging from the presence to absence of significant interactions between a number of COMT haplotypes and indicators of schooling (i.e., in- vs. out-of-school and grade completed) in the prediction of nonverbal intelligence, depending on the parameter specification. However, an investigation of the distribution of corresponding p-values suggested that these positive results were false.

CONCLUSIONS

Convincing evidence that the variation in the COMT gene is associated with individual differences in nonverbal intelligence either directly or through interactions with schooling was not found. p-values produced by the method of testing for haplotype effects employed here may be sensitive to parameter settings, invalid under default settings, and should be checked for validity through simulation.

Neuropsychological testing in a rural African school-age population: evaluating contributions to variability in test performance

This study investigated the psychometric properties of a number of neuropsychological tests adapted for use in sub-Saharan Africa. A total of 308 school-age children in a predominantly rural community completed the tests. These tests were developed to assess skills similar to those measured by assessments of cognitive development published for use in Western contexts. Culturally appropriate adaptations were made to enhance within-population variability. Internal consistency ranged from .70 to .84. Scores on individual tests were related to various background factors at the level of the child, household, and neighborhood. School experience was the most consistent predictor of outcome, accounting for up to 22.9% of the variance observed. Significant associations were identified to determine salient background characteristics that should be taken into account when measuring the discrete effects of disease exposure in similar sociocultural and economic settings.