The required size of cluster randomized trials of nonpharmaceutical interventions in epidemic settings.

To control the SARS-CoV-2 pandemic and future pathogen outbreaks requires an understanding of which nonpharmaceutical interventions are effective at reducing transmission. Observational studies, however, are subject to biases that could erroneously suggest an impact on transmission, even when there is no true effect. Cluster randomized trials permit valid hypothesis tests of the effect of interventions on community transmission.

Global Behaviors, Perceptions, and the Emergence of Social Norms at the Onset of the COVID-19 Pandemic.

We conducted a large-scale survey covering 58 countries and over 100,000 respondents between late March and early April 2020 to study beliefs and attitudes towards citizens' and governments' responses at the onset of the COVID-19 pandemic. Most respondents reported holding normative beliefs in support of COVID-19 containment measures, as well as high rates of adherence to these measures. They also believed that their government and their country's citizens were not doing enough and underestimated the degree to which others in their country supported strong behavioral and policy responses to the pandemic.

Falling living standards during the COVID-19 crisis: Quantitative evidence from nine developing countries.

Despite numerous journalistic accounts, systematic quantitative evidence on economic conditions during the ongoing COVID-19 pandemic remains scarce for most low- and middle-income countries, partly due to limitations of official economic statistics in environments with large informal sectors and subsistence agriculture. We assemble evidence from over 30,000 respondents in 16 original household surveys from nine countries in Africa (Burkina Faso, Ghana, Kenya, Rwanda, Sierra Leone), Asia (Bangladesh, Nepal, Philippines), and Latin America (Colombia). We document declines in employment and income in all settings beginning March 2020.

Interventions to improve adherence to antenatal and postnatal care regimens among pregnant women in sub-Saharan Africa: a systematic review.

Background: Pregnant women in sub-Saharan Africa tend to have low adherence to antenatal and postnatal care regimens, contributing to high infant and child mortality rates. Despite low adherence figures and the high returns from attending antenatal and postnatal care visits, research on interventions to improve adherence is in its infancy. Our aim was to determine the effectiveness of existing interventions to improve adherence to antenatal and postnatal care regimens among pregnant women in sub-Saharan Africa.

Psychological origins of the Industrial Revolution: Why we need causal methods and historians.

Did affluence lead to psychological changes such as reduced discounting, and did these changes facilitate the innovation associated with the Industrial Revolution? I argue that claims of this sort are best made when they can be supported by causal evidence and good psychological measurement. When we have neither identifying variation nor adequate measures, the toolbox of psychologists is not useful.

Is there a social cost of randomization?

Randomized controlled trials, which randomly allocate benefits to a treatment group and not a control group, ascribe differences in post-treatment welfare to the benefits being allocated. However, it is possible that potential recipients' welfare is not only affected by the receipt of the program, but also by the allocation mechanism (procedural utility). In this paper, we ask whether potential recipients support or oppose random allocation of financial benefits, by allowing them to reward or punish an allocator conditional on her choice of allocation mechanism: direct allocation to one recipient vs.

Social determinants of mental disorders and the Sustainable Development Goals: a systematic review of reviews.

Mental health has been included in the UN Sustainable Development Goals. However, uncertainty exists about the extent to which the major social determinants of mental disorders are addressed by these goals. The aim of this study was to develop a conceptual framework for the social determinants of mental disorders that is aligned with the Sustainable Development Goals, to use this framework to systematically review evidence regarding these social determinants, and to identify potential mechanisms and targets for interventions.

Stuff goes wrong, so act now.

Pepper & Nettle make an ambitious and compelling attempt to isolate a common cause of what they call the behavioral constellation of deprivation. We agree with the authors that limited control can indeed help explain part of the difference in observed present-oriented behavior between the poor and the rich. However, we suggest that mortality risk is not the primary mechanism leading to this apparent impatience.

The effect of hydrocortisone administration on intertemporal choice.

Intertemporal choices - decisions involving trade-offs of outcomes at different points in time - are often made under stress. Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, resulting in the release of corticosteroids. Recent studies provide evidence that corticosteroids can induce rapid non-genomic effects focused on immediate resolution of the stressful situation, followed by slower genomic effects focused on long-term recovery after stress.

Measuring self-efficacy, executive function, and temporal discounting in Kenya.

Developing countries have low adherence to medical regimens like water chlorination or antenatal and postnatal care, contributing to high infant and child mortality rates. We hypothesize that high levels of stress affect adherence through temporal discounting, self-efficacy, and executive control. Measurement of these constructs in developing countries requires adaptation of existing measures.

THE SHORT-TERM IMPACT OF UNCONDITIONAL CASH TRANSFERS TO THE POOR: EXPERIMENTAL EVIDENCE FROM KENYA.

We use a randomized controlled trial to study the response of poor households in rural Kenya to unconditional cash transfers from the NGO GiveDirectly. The transfers differ from other programs in that they are explicitly unconditional, large, and concentrated in time. We randomized at both the village and household levels; furthermore, within the treatment group, we randomized recipient gender (wife versus husband), transfer timing (lump-sum transfer versus monthly installments), and transfer magnitude (US$404 PPP versus US$1,525 PPP).

Development of Behavioral Control and Associated vmPFC-DLPFC Connectivity Explains Children's Increased Resistance to Temptation in Intertemporal Choice.

Human civilization is based on the successful pursuit of long-term goals, requiring the ability to forego immediate pleasure for the sake of larger future rewards. This ability improves with age, but the precise cognitive and neural mechanisms underlying its development remain elusive. The developmental changes could result either from younger children valuing immediate rewards more strongly or because older children become better at controlling their impulses.

On the psychology of poverty.

Poverty remains one of the most pressing problems facing the world; the mechanisms through which poverty arises and perpetuates itself, however, are not well understood. Here, we examine the evidence for the hypothesis that poverty may have particular psychological consequences that can lead to economic behaviors that make it difficult to escape poverty. The evidence indicates that poverty causes stress and negative affective states which in turn may lead to short-sighted and risk-averse decision-making, possibly by limiting attention and favoring habitual behaviors at the expense of goal-directed ones.

No effects of psychosocial stress on intertemporal choice.

Intertemporal choices - involving decisions which trade off instant and delayed outcomes - are often made under stress. It remains unknown, however, whether and how stress affects intertemporal choice. We subjected 142 healthy male subjects to a laboratory stress or control protocol, and asked them to make a series of intertemporal choices either directly after stress, or 20 minutes later (resulting in four experimental groups).

The role of testosterone in social interaction.

Although animal researchers established the role of testosterone as a 'social hormone' decades ago, the investigation of its causal influence on human social behaviors has only recently begun. Here, we review and discuss recent studies showing the causal effects of testosterone on social interactions in animals and humans, and outline the basic neurobiological mechanisms that might underlie these effects. Based on these recent findings, we argue that the role of testosterone in human social behavior might be best understood in terms of the search for, and maintenance of, social status.

Both sides retaliate in the Israeli-Palestinian conflict.

Ending violent international conflicts requires understanding the causal factors that perpetuate them. In the Israeli-Palestinian conflict, Israelis and Palestinians each tend to see themselves as victims, engaging in violence only in response to attacks initiated by a fundamentally and implacably violent foe bent on their destruction. Econometric techniques allow us to empirically test the degree to which violence on each side occurs in response to aggression by the other side.

You shouldn't have: your brain on others' crimes.

Our legal system requires assigning responsibility for crimes and deciding on appropriate punishments. A new fMRI study by Buckholtz et al. in this issue of Neuron reveals that the right dorsolateral prefrontal cortex (rDLPFC) plays a key role in these cognitive processes.

Multivariate patterns in object-selective cortex dissociate perceptual and physical shape similarity.

Prior research has identified the lateral occipital complex (LOC) as a critical cortical region for the representation of object shape in humans. However, little is known about the nature of the representations contained in the LOC and their relationship to the perceptual experience of shape. We used human functional MRI to measure the physical, behavioral, and neural similarity between pairs of novel shapes to ask whether the representations of shape contained in subregions of the LOC more closely reflect the physical stimuli themselves, or the perceptual experience of those stimuli.

Privileged coding of convex shapes in human object-selective cortex.

What is the neural code for object shape? Despite intensive research, the precise nature of object representations in high-level visual cortex remains elusive. Here we use functional magnetic resonance imaging (fMRI) to show that convex shapes are encoded in a privileged fashion by human lateral occipital complex (LOC), a region that has been implicated in object recognition. On each trial, two convex or two concave shapes that were either identical or different were presented sequentially.

For love or money: a common neural currency for social and monetary reward.

Two papers in the current issue of Neuron (Izuma et al. and Zink et al.) report that activity in specific regions of the brain, especially the striatum, reflects a common signal of reward in both the economic (e.

Interpreting fMRI data: maps, modules and dimensions.

Neuroimaging research over the past decade has revealed a detailed picture of the functional organization of the human brain. Here we focus on two fundamental questions that are raised by the detailed mapping of sensory and cognitive functions and illustrate these questions with findings from the object-vision pathway. First, are functionally specific regions that are located close together best understood as distinct cortical modules or as parts of a larger-scale cortical map? Second, what functional properties define each cortical map or module? We propose a model in which overlapping continuous maps of simple features give rise to discrete modules that are selective for complex stimuli.

In the eye of the beholder: visual experience and categories in the human brain.

How does experience change representations of visual objects in the brain? Do cortical object representations reflect category membership? In this issue of Neuron, Jiang et al. show that category training leads to sharpening of neural responses in high-level visual cortex; in contrast, category boundaries may be represented only in prefrontal cortex.