Contrasting speed and accuracy approaches to measure executive functions in three low-and middle-income countries.

Executive functions (EF) can be measured by tests assessing accuracy, reaction times and by computing scores which combine these two components. Interpretation issues can arise from the use of different scoring methods across studies. Given that EF measures and their scoring methods are predominantly developed and validated in high income countries, little is known about the generalisability of such methods cross- culturally. The current paper compares two different established scoring approaches for measures of inhibition and cognitive flexibility: difference scores (which utilise reaction time only) and computed scores (combining accuracy and reaction time). We utilised data collected in adulthood from three low- and middle-income birth cohorts (Guatemala, Philippines, South Africa). Non-normal distributions were observed for both scoring methods in all three samples; however, this was more pronounced for the difference score method. Differing distribution patterns were observed across the three cohorts, which was especially evident in the Guatemala cohort, highlighting potential issues with using these methods across diverse populations. The data suggest that the computed scores may be a reliable measure of EF. However, the different ways of scoring and interpreting EF instruments need to be considered carefully for each population before use.

Subjective social status is associated with happiness but not weight status or psychological distress: An analysis of three prospective birth cohorts from low- and middle-income countries.

Background: Subjective social status (SSS, perception of social position relative to a frame of reference) has been associated with physical, mental and socio-emotional wellbeing. However, these associations may be susceptible to unmeasured confounding by life course objective socio-economic position (SEP; such as wealth, education and employment) and life satisfaction. Purpose: To estimate the association of position on ladders of perceived community respect and perceived economic status with weight, distress and wellbeing, independent of objective SEP in cohorts from three low and middle-income countries. Methods: We used data from birth cohorts in Guatemala (n = 1258), Philippines (n = 1323) and South Africa (n = 1393). We estimated the association of perceived community respect and perceived economic status with body mass index (kg/m2), the World Health Organization's Self-Reported Questionnaire-20 (SRQ-20) for psychological distress, and Lyubomirsky's Subjective Happiness Scale. We estimated these associations using robust linear regression models adjusting for indicators of life course objective SEP, early life characteristics, adult covariates, and life satisfaction. Results: Participants in South Africa (age 27-28y) rated themselves higher on average for both the respect (7 vs 5 in Guatemala and 6 in Philippines) and economic (5 vs 3 in Guatemala and 4 in Philippines) ladder measures. Position on neither community respect nor economic ladders were associated with BMI or psychological distress. Higher position on community respect (Guatemala: 0.03, 95%CI: 0.01, 0.04; Philippines: 0.03, 95% CI: 0.02, 0.05; South Africa: 0.07, 95%CI: 0.04, 0.09) and economic (Guatemala: 0.02, 95%CI: 0, 0.04; Philippines: 0.04, 95%CI: 0.02, 0.07; South Africa: 0.07, 95%CI: 0.04, 0.10) ladders were associated with greater happiness. Conclusions: Subjective social status showed small but consistent associations with happiness in birth cohorts independent of life-course SEP.

Executive functions form a single construct and are associated with schooling: Evidence from three low- and middle- income countries.

Measuring executive function (EF) among adults is important, as the cognitive processes involved in EF are critical to academic achievement, job success and mental health. Current evidence on measurement and structure of EF largely come from Western, Educated, Industrialized, Rich and Democratic (WEIRD) countries. However, measuring EF in low-and-middle-income countries (LMICs) is challenging, because of the dearth of EF measures validated across LMICs, particularly measures that do not require extensive training, expensive equipment, or professional administration. This paper uses data from three LMIC cohorts to test the feasibility, validity and reliability of EF assessment in adults using three sub-tests (representing key components of EF) of the NIH Toolbox Cognitive battery. For each cohort, all three EF measures (inhibition, flexibility and working memory) loaded well onto a unidimensional latent factor of EF. Factor scores related well to measures of fluid intelligence, processing speed and schooling. All measures showed good test-retest reliability across countries. This study provides evidence for a set of sound measures of EF that could be used across different cultural, language and socio-economic backgrounds in future LMIC research. Furthermore, our findings extend conclusions on the structure of EF beyond those drawn from WEIRD countries.