Happy in the service of the Company: the purchasing power of VOC salaries at the Cape in the 18th century

This paper contributes to the debate on the level and trajectory of welfare at the Cape of Good Hope during the 18th century. Recent scholarship (for example, Allen 2005) has calculated and compared the levels and evolution of real wages in various European and Asian economies since the early modern period. To this lit-erature we add evidence for unskilled and skilled workers of the Dutch East India Company at the Cape of Good Hope during the 18th century, following De Zwart (2009; 2011), who recently presented evidence for unskilled workers in the Cape for the latter half of the 17th century and the 18th century. We calculate job-specific real wages in a three-step argument; from the narrowest international comparison of wage rates in terms of silver content to one based on a basket of widely consumed goods. The paper’s contributions lie in the breadth of the com-parisons, the inclusion of skilled workers in the comparison and the adaptation of the consumption basket to local conditions and relative prices at the Cape. The results support the hypothesis that at the start of the 18th century, the Cape Col-ony was relatively poor on an international comparison, but as the century un-folded, gained considerably on even the richest contemporary societies.Real wages, Dutch East India Company (VOC), Cape Colony, Compari-sons of living standards, Economic history of South Africa, Economic history of the Cape Colony

A new and direct test of the ‘gender bias’ in multiple-choice questions

Local and international research has identified a bias in favour of male students with MCQs. If correctly identified, this bias holds implications for reasonable assessment strategies in economics courses. A standard method used in the literature is to relate student performance to various features of the learning environment (such as the type of question) and to student-specific characteristics (such as past performance and lecture attendance). A more direct approach is possible: we set comparable questions (in three categories – graphs, quantitative and theory) in the written and MCQ sections of three tests in the introductory microeconomics course at the University of Stellenbosch. This allows a direct comparison between the performance of male and female students (overall and per question category), without the need to model overall student performance. The number of students in this course, almost 2000, offers a suitably large sample for studying this question. Our evidence does not confirm the strong claims about gender bias in the literature; indeed we find the opposite: a strong positive female gender effect, but for written questions only. We also find no evidence of higher risk-aversion by female students towards MCQ questions with negative marking.Gender bias, Economics education

Democracy and the feedback mechanism in Botswana

No country knows what the right policy choices are because we live in a world of uncertainty. One way to improve policy choices is to ensure a good feedback mechanism. With feedback, current policy choices might be altered to ensure a better fit with prevailing circumstances. Botswana seems to be an interesting case study, where the deportation of a well-known academic placed a lid on its history of openness and public debate. This paper explores why a government respected for good management would choose to display such signs of autocracy, and how it is possible within the prevailing government institutions.Poverty, Botswana, Botswana government, Democracy, Feedback mechanism, Institutions

Institutions and Institutional Change in Zambia

Research has shown a positive correlation between extractive colonisation and low post-colonial economic growth. This paper provides case study research to explore the possibility that post-colonial extractive institutions were already present in pre-colonial times. In Zambia’s case this is indeed true. Extractive institutions existed in Zambia before colonisation, and colonisation certainly did not improve on them. The question whether countries like Zambia are doomed for failure is also considered, and it is concluded that an environment that allows experimentation is supportive of economic growth and development. With an authoritative regime during the Second Republic, feedback on policy decisions was limited and may provide more of an answer to bad post-colonial economic performance than extractive colonisation.Institutions, Institutional Change, Colonisation, Zambia

The limits of laws : traffic law enforcement in South Africa

CITATION: Du Plessis, S., Jansen, A. & Siebrits, K. 2020. The limits of laws : traffic law enforcement in South Africa. South African Journal of Economic and Management Sciences, 23(1):a3430, doi:10.4102/sajems.v23i1.3430.The original publication is available at https://sajems.orgBackground: The aim of many public policies is to change behaviour. Governments tend to rely on regulations, taxes and subsidies to effect such change. These measures, which affect agents’ economic incentives, have a mixed record. A key insight of the New Institutional Economics is that the efficacy of such formal institutions depends on the strength of their enforcement and the extent to which they are compatible with prevailing informal institutions. Aim: This article uses the road safety situation in South Africa as a case study to explore aspects of the relationships among formal institutions, law enforcement and informal institutions. Setting: South Africa has a strong suite of road safety laws but poor road safety outcomes. Methods: The article draws on ideas about the relationships between formal institutions, law enforcement and informal institutions to undertake a case study of the road safety situation in South Africa. Results: The article argues that improved law enforcement cannot fully solve the problem; complementary changes to the informal institutions shaping the behaviour of road users are essential. Conclusion: Institutional economists have to take a greater interest in the insights of research in behavioural economics, behavioural and cognitive science and other disciplines in order to provide useful advice in settings where such change is an important policy objective.https://sajems.org/index.php/sajems/article/view/3430Publisher's versio

Brain ageing in schizophrenia: evidence from 26 international cohorts via the ENIGMA Schizophrenia consortium

Schizophrenia (SZ) is associated with an increased risk of life-long cognitive impairments, age-related chronic disease, and premature mortality. We investigated evidence for advanced brain ageing in adult SZ patients, and whether this was associated with clinical characteristics in a prospective meta-analytic study conducted by the ENIGMA Schizophrenia Working Group. The study included data from 26 cohorts worldwide, with a total of 2803 SZ patients (mean age 34.2 years; range 18-72 years; 67% male) and 2598 healthy controls (mean age 33.8 years, range 18-73 years, 55% male). Brain-predicted age was individually estimated using a model trained on independent data based on 68 measures of cortical thickness and surface area, 7 subcortical volumes, lateral ventricular volumes and total intracranial volume, all derived from T1-weighted brain magnetic resonance imaging (MRI) scans. Deviations from a healthy brain ageing trajectory were assessed by the difference between brain-predicted age and chronological age (brain-predicted age difference [brain-PAD]). On average, SZ patients showed a higher brain-PAD of +3.55 years (95% CI: 2.91, 4.19; I2 = 57.53%) compared to controls, after adjusting for age, sex and site (Cohen's d = 0.48). Among SZ patients, brain-PAD was not associated with specific clinical characteristics (age of onset, duration of illness, symptom severity, or antipsychotic use and dose). This large-scale collaborative study suggests advanced structural brain ageing in SZ. Longitudinal studies of SZ and a range of mental and somatic health outcomes will help to further evaluate the clinical implications of increased brain-PAD and its ability to be influenced by interventions

Remodeling of the Cortical Structural Connectome in Posttraumatic Stress Disorder:Results from the ENIGMA-PGC PTSD Consortium

BACKGROUND: Posttraumatic stress disorder (PTSD) is accompanied by disrupted cortical neuroanatomy. We investigated alteration in covariance of structural networks associated with PTSD in regions that demonstrate the case-control differences in cortical thickness (CT) and surface area (SA). METHODS: Neuroimaging and clinical data were aggregated from 29 research sites in >1,300 PTSD cases and >2,000 trauma-exposed controls (age 6.2-85.2 years) by the ENIGMA-PGC PTSD working group. Cortical regions in the network were rank-ordered by effect size of PTSD-related cortical differences in CT and SA. The top-n (n = 2 to 148) regions with the largest effect size for PTSD > non-PTSD formed hypertrophic networks, the largest effect size for PTSD < non-PTSD formed atrophic networks, and the smallest effect size of between-group differences formed stable networks. The mean structural covariance (SC) of a given n-region network was the average of all positive pairwise correlations and was compared to the mean SC of 5,000 randomly generated n-region networks. RESULTS: Patients with PTSD, relative to non-PTSD controls, exhibited lower mean SC in CT-based and SA-based atrophic networks. Comorbid depression, sex and age modulated covariance differences of PTSD-related structural networks. CONCLUSIONS: Covariance of structural networks based on CT and cortical SA are affected by PTSD and further modulated by comorbid depression, sex, and age. The structural covariance networks that are perturbed in PTSD comport with converging evidence from resting state functional connectivity networks and networks impacted by inflammatory processes, and stress hormones in PTSD

A Comparison of Methods to Harmonize Cortical Thickness Measurements Across Scanners and Sites

Results of neuroimaging datasets aggregated from multiple sites may be biased by site-specific profiles in participants’ demographic and clinical characteristics, as well as MRI acquisition protocols and scanning platforms. We compared the impact of four different harmonization methods on results obtained from analyses of cortical thickness data: (1) linear mixed-effects model (LME) that models site-specific random intercepts (LME INT), (2) LME that models both site-specific random intercepts and age-related random slopes (LME INT+SLP), (3) ComBat, and (4) ComBat with a generalized additive model (ComBat-GAM). Our test case for comparing harmonization methods was cortical thickness data aggregated from 29 sites, which included 1,340 cases with posttraumatic stress disorder (PTSD) (6.2–81.8 years old) and 2,057 trauma-exposed controls without PTSD (6.3–85.2 years old). We found that, compared to the other data harmonization methods, data processed with ComBat-GAM was more sensitive to the detection of significant case-control differences (Χ 2(3) = 63.704, p < 0.001) as well as case-control differences in age-related cortical thinning (Χ 2(3) = 12.082, p = 0.007). Both ComBat and ComBat-GAM outperformed LME methods in detecting sex differences (Χ 2(3) = 9.114, p = 0.028) in regional cortical thickness. ComBat-GAM also led to stronger estimates of age-related declines in cortical thickness (corrected p-values < 0.001), stronger estimates of case-related cortical thickness reduction (corrected p-values < 0.001), weaker estimates of age-related declines in cortical thickness in cases than controls (corrected p-values < 0.001), stronger estimates of cortical thickness reduction in females than males (corrected p-values < 0.001), and stronger estimates of cortical thickness reduction in females relative to males in cases than controls (corrected p-values < 0.001). Our results support the use of ComBat-GAM to minimize confounds and increase statistical power when harmonizing data with non-linear effects, and the use of either ComBat or ComBat-GAM for harmonizing data with linear effects

Smaller total and subregional cerebellar volumes in posttraumatic stress disorder:a mega-analysis by the ENIGMA-PGC PTSD workgroup

Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p -FDR &lt; 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.</p

Smaller total and subregional cerebellar volumes in posttraumatic stress disorder:a mega-analysis by the ENIGMA-PGC PTSD workgroup

Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p -FDR &lt; 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.</p