Maternal stress during pregnancy and children's diet: Evidence from a population of low socioeconomic status.

OBJECTIVES: This study examined the relationship between maternal exposure to stress during pregnancy and children's food preferences and diet in a population of low socioeconomic status. METHODS: Indices of exposure to stress were constructed based on retrospective self-reported experience of stressful events during pregnancy (e.g., death of close family member, relationship difficulties, legal issues, health issues, financial issues, or other potentially stressful event[s]). Data were collected for >200 mothers of a low socioeconomic status with a child age 2 to 12 y. Data on mothers' body mass index, current exposure to stress, current diet, and diet during pregnancy were collected at the same time, as well as data on children's food preferences and current diet as reported by the mothers. Indices of the healthiness of food preferences and diet were constructed and used as outcome variables. RESULTS: Maternal exposure to stress during pregnancy significantly predicts children's food and taste preferences, as well as their diet, in regression models controlling for maternal diet, current maternal stress, and demographic characteristics of both the child and mother. Higher average stress during pregnancy is linked with significantly less healthy food preferences and diet, as well as with weaker preferences for sour and bitter foods. This relationship is observed across different age groups. CONCLUSIONS: Maternal exposure to stress during pregnancy could have long-term detrimental effects on dietary outcomes and thereby on health conditions related to diet. Prenatal care and preconception counseling could be critical to develop preventive strategies to improve public health.

Mind training, stress and behaviour-A randomised experiment.

In this paper, we evaluate the effects of a psychological training, called Mindfulness-Based Stress Reduction (MBSR) on stress and risk and time preferences. MBSR is a well-known psychological technique, which is believed to improve self-control and reduce stress. We conduct the experiment with 139 participants, half of whom receive the MBSR training, while the other half are asked to watch a documentary series, both over 4 consecutive weeks. Using a range of self-reported and physiological measures (such as cortisol measures), we find evidence that mindfulness training reduces perceived stress, but we only find weak evidence of effects on risk and inter-temporal attitudes.

Rewarding behavior with a sweet food strengthens its valuation.

Sweet foods are commonly used as rewards for desirable behavior, specifically among children. This study examines whether such practice may contribute to reinforce the valuation of these foods. Two experiments were conducted, one with children, the other with rats. The first study, conducted with first graders (n = 214), shows that children who receive a food reward for performing a cognitive task subsequently value the food more compared to a control group who received the same food without performing any task. The second study, conducted on rats (n = 64), shows that rewarding with food also translates into higher calorie intake over a 24-hour period. These results suggest that the common practice of rewarding children with calorie-dense sweet foods is a plausible contributing factor to obesity and might therefore be ill advised.

Unequal consequences of Covid 19: representative evidence from six countries.

Covid-19 and the measures taken to contain it have led to unprecedented constraints on work and leisure activities, across the world. This paper uses nationally representative surveys to document how people of different ages and incomes have been affected in the early phase of the pandemic. The data was collected in six countries (China, South Korea, Japan, Italy, UK, and US) in the third week of April 2020. First, we document changes in job circumstances and social activities. Second, we document self-reported negative and positive consequences of the crisis on well-being. We find that young people have experienced more drastic changes to their life and have been most affected economically and psychologically. There is less of a systematic pattern across income groups. While lower income groups have been more affected economically, higher income groups have experienced more changes in their social life and spending. A large fraction of people of low and high income groups report negative effects on well-being.

Socio-demographic factors associated with self-protecting behavior during the Covid-19 pandemic.

Given the role of human behavior in the spread of disease, it is vital to understand what drives people to engage in or refrain from health-related behaviors during a pandemic. This paper examines factors associated with the adoption of self-protective health behaviors, such as social distancing and mask wearing, at the start of the Covid-19 pandemic in the USA. These behaviors not only reduce an individual's own risk of infection but also limit the spread of disease to others. Despite these dual benefits, universal adoption of these behaviors is not assured. We focus on the role of socioeconomic differences in explaining behavior, relying on data collected in April 2020 during the early stages of the Covid-19 pandemic. The data include information on income, gender and race along with unique variables relevant to the current pandemic, such as work arrangements and housing quality. We find that higher income is associated with larger changes in self-protective behaviors. These gradients are partially explained by the fact that people with less income are more likely to report circumstances that make adopting self-protective behaviors more difficult, such as an inability to tele-work. Both in the USA and elsewhere, policies that assume universal compliance with self-protective measures-or that otherwise do not account for socioeconomic differences in the costs of doing so-are unlikely to be effective or sustainable.

A computer-based incentivized food basket choice tool: Presentation and evaluation.

OBJECTIVE: To develop and evaluate a low-cost computer-based tool to elicit dietary choices in an incentive compatible manner, which can be used on-line or as part of a laboratory study. METHODS: The study was conducted with around 255 adults. Respondents were asked to allocate a fixed monetary budget across a choice of around a hundred grocery items with the prospect of receiving these items with some probability delivered to their home by a real supermarket. The tool covers a broad range of food items, allows inference of macro-nutrients and calories, and allows the researcher to fix the choice set participants can choose from. We compare the information derived from our incentivized tool, and compare it to alternative low-cost ways of measuring dietary intake, namely the food frequency questionnaire and a one-shot version of the 24-hour dietary recall, which are both based on self-reports. We compare the calorie intake indicators derived from each tool with a number of biometric measures for each subject, namely weight, body-mass-index (BMI) and waist size. RESULTS: The results show that the dietary information collected is only weakly correlated across the three methods. We find that only the calorie intake measure from our incentivized tool is positively and significantly related to each of the biometric indicators. Specifically, a 10% increase in calorie intake is associated with a 1.5% increase in BMI. By contrast, we find no significant correlations for either of the two measures based on self-reports. CONCLUSION: The computer-based tool is a promising new, low-cost measure of dietary choices, particularly in one-shot situations where such behaviours are only observed once, whereas other tools like 24-hour dietary recalls and food frequency questionnaires may be more suited when they are administered repeatedly. The tool may be useful for research conducted with limited time and budget.

How private is private information? The ability to spot deception in an economic game.

We provide experimental evidence on the ability to detect deceit in a buyer-seller game with asymmetric information. Sellers have private information about the value of a good and sometimes have incentives to mislead buyers. We examine if buyers can spot deception in face-to-face encounters. We vary whether buyers can interrogate the seller and the contextual richness. The buyers' prediction accuracy is above chance, and is substantial for confident buyers. There is no evidence that the option to interrogate is important and only weak support that contextual richness matters. These results show that the information asymmetry is partly eliminated by people's ability to spot deception.

The determinants of food choice.

Health nudge interventions to steer people into healthier lifestyles are increasingly applied by governments worldwide, and it is natural to look to such approaches to improve health by altering what people choose to eat. However, to produce policy recommendations that are likely to be effective, we need to be able to make valid predictions about the consequences of proposed interventions, and for this, we need a better understanding of the determinants of food choice. These determinants include dietary components (e.g. highly palatable foods and alcohol), but also diverse cultural and social pressures, cognitive-affective factors (perceived stress, health attitude, anxiety and depression), and familial, genetic and epigenetic influences on personality characteristics. In addition, our choices are influenced by an array of physiological mechanisms, including signals to the brain from the gastrointestinal tract and adipose tissue, which affect not only our hunger and satiety but also our motivation to eat particular nutrients, and the reward we experience from eating. Thus, to develop the evidence base necessary for effective policies, we need to build bridges across different levels of knowledge and understanding. This requires experimental models that can fill in the gaps in our understanding that are needed to inform policy, translational models that connect mechanistic understanding from laboratory studies to the real life human condition, and formal models that encapsulate scientific knowledge from diverse disciplines, and which embed understanding in a way that enables policy-relevant predictions to be made. Here we review recent developments in these areas.

Incentives and children's dietary choices: A field experiment in primary schools.

We conduct a field experiment in 31 primary schools in England to test the effectiveness of different temporary incentives on increasing choice and consumption of fruit and vegetables at lunchtime. In each treatment, pupils received a sticker for choosing a fruit or vegetable at lunch. They were eligible for an additional reward at the end of the week depending on the number of stickers accumulated, either individually (individual scheme) or in comparison to others (competition). Overall, we find no significant effect of the individual scheme, but positive effects of competition. For children who had margin to increase their consumption, competition increases choice of fruit and vegetables by 33% and consumption by 48%. These positive effects generally carry over to the week immediately following the treatment, but are not sustained effects six months later. We also find large differences in effectiveness across demographic characteristics such as age and gender.

Players of Matching Pennies automatically imitate opponents' gestures against strong incentives.

There is a large body of evidence of apparently spontaneous mimicry in humans. This phenomenon has been described as "automatic imitation" and attributed to a mirror neuron system, but there is little direct evidence that it is involuntary rather than intentional. Cook et al. supplied the first such evidence in a unique strategic game design that gave all subjects a pecuniary incentive to avoid imitation [Cook R, Bird G, Lünser G, Huck S, Heyes C (2012) Proc Biol Sci 279(1729):780-786]. Subjects played Rock-Paper-Scissors repeatedly in matches between fixed pairs, sometimes with one and sometimes with both subjects blindfolded. The frequency of draws in the blind-blind condition was at chance, but in the blind-sighted condition it was significantly higher, suggesting automatic imitation had occurred. Automatic imitation would raise novel issues concerning how strategic interactions are modeled in game theory and social science; however, inferring automatic imitation requires significant incentives to avoid it, and subjects' incentives were less than 3 US cents per 60-game match. We replaced Cook et al.'s Rock-Paper-Scissors with a Matching Pennies game, which allows far stronger incentives to avoid imitation for some subjects, with equally strong incentives to imitate for others. Our results are important in providing evidence of automatic imitation against significant incentives. That some of our subjects had incentives to imitate also enables us clearly to distinguish intentional responding from automatic imitation, and we find evidence that both occur. Thus, our results strongly confirm the occurrence of automatic imitation, and illuminate the way that automatic and intentional processes interact in a strategic context.

Healthy school meals and educational outcomes.

This paper provides field evidence on the effects of diet on educational outcomes, exploiting a campaign lead in the UK in 2004, which introduced drastic changes in the meals offered in the schools of one borough - Greenwich - shifting from low-budget processed meals towards healthier options. We evaluate the effect of the campaign on educational outcomes in primary schools using a difference in differences approach; comparing educational outcomes in primary schools (Key Stage 2 outcomes more specifically) before and after the reform, using the neighbouring Local Education Authorities as a control group. We find evidence that educational outcomes did improve significantly in English and Science. We also find that authorized absences - which are most likely linked to illness and health - fell by 14%.

Anthropometry of love: height and gender asymmetries in interethnic marriages.

Both in the UK and in the US, we observe puzzling gender asymmetries in the propensity to outmarry: Black men are more likely to have white spouses than Black women, but the opposite is true for Chinese: Chinese men are half less likely to be married to a White person than Chinese women. We argue that differences in height distributions, combined with a simple preference for the husband to be taller than the wife, can help explain these ethnic-specific gender asymmetries. Blacks are taller than Asians, and we argue that this significantly affects their marriage prospects with whites. We provide empirical support for this hypothesis using data from the Millennium Cohort Study. Specifically, we find that ethnic differences in propensity to intermarry with Whites shrink when we control for the proportion of suitable partners with respect to height.