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Self-control is of vital importance for human wellbeing. Hare et al. (2009) were among the first to provide empirical evidence on the neural correlates of self-control. This seminal study profoundly impacted theory and empirical work across multiple fields. To solidify the empirical evidence supporting self-control theory, we conducted a preregistered replication of this work. Further, we tested the robustness of the findings across analytic strategies. Participants underwent functional magnetic resonance imaging while rating 50 food items on healthiness and tastiness and making choices about food consumption. We closely replicated the original analysis pipeline and supplemented it with additional exploratory analyses to follow-up on unexpected findings and to test the sensitivity of results to key analytical choices. Our replication data provide support for the notion that decisions are associated with a value signal in ventromedial prefrontal cortex (vmPFC), which integrates relevant choice attributes to inform a final decision. We found that vmPFC activity was correlated with goal values regardless of the amount of self-control and it correlated with both taste and health in self-controllers but only taste in non-self-controllers. We did not find strong support for the hypothesized role of left dorsolateral prefrontal cortex (dlPFC) in self-control. The absence of statistically significant group differences in dlPFC activity during successful self-control in our sample contrasts with the notion that dlPFC involvement is required in order to effectively integrate longer-term goals into subjective value judgments. Exploratory analyses highlight the sensitivity of results (in terms of effect size) to the analytical strategy, for instance, concerning the approach to region-of-interest analysis.

The development of addictive behaviors has been suggested to be related to a transition from goal-directed to habitual decision making. Stress is a factor known to prompt habitual behavior and to increase the risk for addiction and relapse. In the current study, we therefore used functional MRI to investigate the balance between goal-directed 'model-based' and habitual 'model-free' control systems and whether acute stress would differentially shift this balance in gambling disorder (GD) patients compared to healthy controls (HCs). Using a within-subject design, 22 patients with GD and 20 HCs underwent stress induction or a control condition before performing a multistep decision-making task during fMRI. Salivary cortisol levels showed that the stress induction was successful. Contrary to our hypothesis, GD patients did not show impaired goal-directed 'model-based' decision making, which remained similar to HCs after stress induction. Bayes factors provided three times more evidence against a difference between the groups or a group-by-stress interaction on the balance between model-based and model-free decision making. Similarly, no differences were found between groups and conditions on the neural estimates of model-based or model-free decision making. These results challenge the notion that GD is related to an increased reliance on habitual (or decreased goal-directed) control, even during stress.

Background As snacking can be considered a cornerstone of an unhealthy diet, investigating psychological drivers of snacking behaviour is urgent, and therefore the purpose of this study. Socio-economic position (SEP) and stress are known to affect many behaviours and outcomes, and were therefore focal points in the study. Methods In a cross-sectional survey study, we examined whether Socio-economic position (SEP) would amplify associations between heightened stress levels and self-reported negative-affect related reasons for snacking. Next, we investigated whether Socio-economic position (SEP) predicted frequency of snacking behaviour, and how stress and other reasons for snacking could explain this association. Outcome measures were reasons people indicated for snacking, and frequency of snacking behaviour. Results Analyses revealed that people seem to find more reasons to snack when they are stressed, and that this association was more pronounced for people with a high compared to low socio-economic position. Furthermore, a higher socio-economic position was associated with a higher frequency of snacking, and both snacking to reward oneself and snacking because of the opportunity to do so remained significant mediators. Conclusion Whereas low socio-economic position was associated with higher stress levels, this did not translate into increased snacking. Contrarily, those with higher socio-economic position could be more prone to using ‘reasons to snack’, which may result in justification of unhealthy snacking behaviour.

On March 15, 2020, the Dutch Government implemented COVID-19 lockdown measures. Although self-quarantine and social-distancing measures were implemented, restrictions were less severe compared to several other countries. The aim of this study was to assess changes in eating behavior and food purchases among a representative adult sample in the Netherlands (n = 1030), five weeks into lockdown. The results show that most participants did not change their eating behaviors (83.0%) or food purchases (73.3%). However, socio-demographic differences were observed among those that reported changes during lockdown. For example, participants with overweight (OR = 2.26, 95%CI = 1.24–4.11) and obesity (OR = 4.21, 95%CI = 2.13–8.32) were more likely to indicate to eat unhealthier during lockdown compared to participants with a healthy weight. Those with a high educational level (OR = 2.25, 95%-CI = 1.03–4.93) were also more likely to indicate to eat unhealthier during lockdown compared to those with a low educational level. Older participants were more likely to indicate to experience no differences in their eating behaviors compared to those of younger age, who were more likely to indicate that they ate healthier (OR = 1.03, 95%CI = 1.01–1.04) as well as unhealthier (OR = 1.04, 95%CI = 1.02–1.06) during lockdown. Participants with obesity were more likely to indicate to purchase more chips/snacks (OR = 2.79, 95%CI = 1.43–5.45) and more nonalcoholic beverages (OR = 2.74, 95%CI = 1.36–5.50) during lockdown in comparison with those with a healthy weight. Of those that used meal delivery services before, 174 (29.5%) indicated to use meal delivery services more frequently during lockdown. Although the results confirm the persistence of dietary routines, profound socio-demographic differences were observed for those that did report changes. Especially for individuals with overweight and obesity, the lockdown has taken its toll on healthy dietary choices. Further research should unravel underlying mechanisms for these observations.

Nudges have been proposed as an effective tool to stimulate influenza vaccination uptake in healthcare workers. However, the success of such nudges in practice is heavily reliant on their acceptance by the intended healthcare worker population, which has not been thoroughly examined to date. This study investigated healthcare workers’ acceptability of diverse influenza vaccination nudges implemented in a real-world vaccination campaign and explored the relationship between nudge acceptability and vaccination uptake. A cross-sectional study was conducted among 244 Dutch hospital employees, following a hospital-wide influenza vaccination nudging intervention. A survey assessed healthcare workers’ perceived acceptability of ten distinct influenza vaccination nudges, along with their vaccination status and relevant covariates (e.g., general perceptions regarding influenza vaccination of healthcare workers). Influenza vaccination nudges in general were deemed acceptable, with reward-based nudges being the least accepted, while digital vaccination forms, a mobile vaccination post, peer vaccination, and digital vaccination reminders were most appreciated. A higher overall acceptance of these nudges was associated with a greater likelihood of being vaccinated, particularly in healthcare workers with favorable perceptions of influenza vaccination usefulness. Our findings suggest that influenza vaccination nudges are an accepted means to systematically promote immunization of healthcare workers, and thus present a viable strategy for public health policies aimed at this group.

SamenvattingVaccinatie is een belangrijk onderdeel in de bestrijding van het COVID-19-virus. Een voorspeller van het aandeel mensen dat daadwerkelijk een vaccinatie zal nemen is de vaccinatiebereidheid onder de bevolking. Uit buitenlandse literatuur blijkt dat de vaccinatiebereidheid onder mensen met een lagere sociaaleconomische status lager ligt dan onder andere groepen. In deze bijdrage beschrijven we in hoeverre dit ook in Nederland het geval is en laten we zien hoe risicoperceptie, vertrouwen in de werking en veiligheid van het vaccin en gezondheidsvaardigheden hier mogelijk mee samenhangen. Tot slot belichten we een aantal interventiestrategieën die positief aan de vaccinatiebereidheid onder laagopgeleiden kunnen bijdragen.

Vaccination of youth could be key to preventing future outbreaks of SARS-CoV-2. Given the limited direct health benefit for young people, it is important to understand how youth themselves perceive obtaining a vaccination. This survey study in a representative sample of Dutch youth aged 12–18 showed that 73% were willing to get vaccinated against COVID-19. In regression analyses, vaccination willingness was strongly related to age, perceived personal (protect own health) and societal benefits (to get rid of restrictive policies), and their peers’ and parents’ vaccination uptake. Negative associations with vaccination willingness were perceived side-effects and potential unknown long term consequences. On-going and transparent communication with up-to-date information about safety and risks, delivered by independent and trusted experts (as perceived by the recipients) seems important for addressing questions and concerns. Local information sessions for youth and parents where a vaccination can be obtained without appointment could have merit in addition to mass media communication.

The outbreak of COVID-19 has turned out to be a major challenge to societies all over the globe. Curbing the pandemic requires rapid and extensive behavioural change to limit social interaction, including physical distancing. In this study, we tested the notion that inducing empathy for people vulnerable to the virus may result in actual distancing behaviour beyond the mere motivation to do so. In a large field experiment with a sequential case–control design, we found that (a) empathy prompts may increase distancing as assessed by camera recordings and (b) effectiveness of prompts depends on the dynamics of the pandemic and associated public health policies. In sum, the present study demonstrates the potential of empathy-generating interventions to promote pro-social behaviour and emphasizes the necessity of field experiments to assess the role of context before advising policy makers to implement measures derived from behavioural science. Please refer to Supplementary Material to find this article's Community and Social Impact Statement.

Nudges are behavioral interventions to subtly steer citizens’ choices toward “desirable” options. An important topic of debate concerns the legitimacy of nudging as a policy instrument, and there is a focus on issues relating to nudge transparency, the role of preexisting preferences people may have, and the premise that nudges primarily affect people when they are in “irrational” modes of thinking. Empirical insights into how these factors affect the extent to which people are susceptible to nudge influence (i.e., “nudgeable”) are lacking in the debate. This article introduces the new concept of nudgeability and makes a first attempt to synthesize the evidence on when people are responsive to nudges. We find that nudge effects do not hinge on transparency or modes of thinking but that personal preferences moderate effects such that people cannot be nudged into something they do not want. We conclude that, in view of these findings, concerns about nudging legitimacy should be softened and that future research should attend to these and other conditions of nudgeability.

Background Few studies have assessed the use of dietary supplements, anabolic androgenic steroids (AAS) and selective androgen receptor modulators (SARM) in male gym users. The comparison of physical appearance with others on social media and the exposure to fitness-related content on social media (i.e., image-centric social media use) may have a profound role in using these compounds due to its role in creating negative body images in male gym users. Objective Provide contemporary data on the use of dietary supplements, AAS and SARM among young male gym users, and test the hypothesis that social media is associated with the use of dietary supplements, AAS and SARM, as a result of a negative body image. Methods In this cross-sectional study, conducted in the Netherlands, male gym users (N = 2269; 24 ± 6 years) completed an online questionnaire including self-reported measures regarding resistance training participation, image-centric social media use, dietary supplement intake, and body image. The prevalence of AAS and SARM use was assessed with randomized response, a technique to ask sensitive questions indirectly. Results Of all participants, 83% used ergogenic dietary supplements (mainly protein and creatine), and an estimated 9 versus 2.7% had ever used AAS versus SARM. Image-centric social media use was positively associated with the use of dietary supplements (r = .26; p p r = .34; p Conclusions The use of dietary supplements in young male gym users is exorbitant, with the use of AAS and SARM being substantial. Image-centric social media use is positively associated with the use of dietary supplements and AAS.

This erratum describes changes made in our previously published study protocol [1], as the occurrence of the COVID-19 pandemic has led to insurmountable challenges in feasibility to maintain the original design. The planned start of participant recruitment for the trial coincided with the first COVID-19 lockdown in the Netherlands starting March 16 2020. As a result, the start of the study was postponed by 11 months. The continued/renewed lockdown hampered face-to-face contact and thus some planned physical measurements. These circumstances required adaptation to remote data collection methods, revision of recruitment goals and of the primary study outcomes, and inclusion of additional study sites to secure adequate participant inclusion rates. Therefore, below we present the revised methodology of the Supreme Nudge parallel cluster-randomised controlled supermarket trial. All changes made to the original protocol were reviewed and approved by the Medical Ethics Review Committee of VU University Medical Center (reference number: 2019.334) prior to implementation. Study design As previously described [1], the Supreme Nudge supermarket trial is a cluster randomised controlled design, with nudging and pricing strategies implemented at the supermarket level (Fig. 1). The original protocol described two groups of intervention supermarkets (nudging or nudging and pricing) and one group of control supermarkets. This design is revised to two groups in total; supermarkets are randomized to an intervention group receiving the combination of healthy food nudges and pricing strategies or a control group receiving no intervention. The groups for the mobile physical activity (PA) coaching app remain unchanged; the coaching app is randomised at the individual level across all supermarket clusters. The original protocol described inclusion of eight supermarkets and an intervention duration and followup time of 12 months [1]. However, recruitment among eight supermarkets led to insufficient participant enrolment, which necessitated additional inclusion of four additional supermarket locations. As a result, eight out of 12 supermarkets were enrolled within the study in the spring of 2021 and the four additional supermarket locations in the autumn of 2021. For these four stores, the intervention implementation and the follow-up time is only feasible for a duration of six months due to ending of project funding by the summer of 2022. Supermarkets Twelve supermarkets of a Dutch supermarket chain that meet all of the following criteria are included in the study: i) Regular supermarket format, i.e., no compact store size (unchanged criterion); ii) Located in a lower SEP neighbourhood (below average postal code SEP-scores of The Netherlands Institute for Social Research [2]) (unchanged criterion); iii) Implemented a new cash register system which allowed implementation of pricing strategies (new criterion). Participants Participants are men and women living in a low SEP neighbourhood. Used inclusion criteria are: i) Aged 30–80 years (was 45–75 years in the original protocol); ii) Living in a lower SEP neighbourhood surrounding one of the participating supermarkets (was combined with having a practical vocational education level in the original protocol); iii) Self-report to do (or report their partner does) more than half of the household grocery shopping at the selected supermarket and plan to continue visiting for the next (half) year (unchanged criterion); iv) Provide written informed consent (unchanged criterion); v) Able to communicate in the Dutch language (unchanged criterion). Trial outcomes We revised our primary outcomes to changes in the dietary intake (DHD15-index scores [3]) over 6 or 12 months for all intervention supermarket participants compared to control participants. Secondary outcomes now include cardiometabolic outcomes, including HbA1c, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, total cholesterol (TC), TC/ HDL-ratio, triglycerides (TG) and waist circumference. The planned blood pressure measurement was excluded due to feasibility limitations when we needed to adapt to remote data collecting methods. Regarding the other previously described secondary outcomes, some questionnaire items relating to walking behaviours and social cognitive factors have been revised. Furthermore, we added healthy dietary intake per food group based on the sub-scores of the DHD15-index scores [3], items on selfreported walking behaviour, use of the coaching app and walking app, privacy concerns relating to the coaching app and on perceptions on healthy eating and on grocery shopping (described in detail below). Sample size The current set-up of the trial is powered to detect a mean change of 5 points on the DHD15-index, assuming a 15 point standard deviation of the mean change. This standard deviation is based on the first round of collected baseline data in the spring of 2021, where the standard deviation of the DHD15-index score was 19.9. To estimate a standard deviation around the mean difference, we used the formula σ √[2(1-ρ)], assuming a ρ of 0.75, resulting in a standard deviation of the mean difference of 14.1. With 80% power and a two-sided type 1 error rate of 0.05, the trial required 141 participants in each supermarket arm. To allow for 25% drop out, a minimum of 176 participants need to be recruited per arm, resulting in 352 participants in total. We set our recruitment goal at 360 participants, resulting in a mean of 30 participants per cluster (i.e., supermarket). We did not use a design factor, as our estimations based on our first round of baseline data showed no correlation for observations of DHD15-index scores between study sites. Recruitment As planned, a stepwise recruitment strategy was applied. However, active recruitment possibilities were limited due to the COVID-19 lockdown and planned neighbourhood tailored community-outreach methods and active recruitment at local events were not possible. As alternative active recruitment method participants were requested via a phone call to encourage their partner or neighbours to register for eligibility screening (promoting word-of-mouth). Recruiting in-store by the research team was conducted as soon as COVID-19 related restrictions allowed, which started approximately halfway through the recruitment period. Furthermore, additional passive recruitment strategies were applied throughout the whole recruitment period. The initial planned passive strategies started with local advertisements including news articles in local (online) media, flyers distributed in the supermarket and by mail, posters displayed in-store and at some other locations in the neighbourhood (e.g., physiotherapy practice), postal invitation letters sent to every household of the municipality around the included supermarkets, and municipality targeted Facebook advertisements. The additional passive strategies were an email invitation to the supermarket’s customer panels, Facebook posts on the participating supermarket pages, and advertisement on the website of the Dutch Heart Foundation (study funder). Study procedures All data collection procedures are adapted towards remote data collection methods, instead of inviting participants to a study location. The eligibility screening and inclusion procedure was as follows: Interested supermarket customers registered via the project website, by telephone, or mailing a register form which was included on the supermarket flyer. Next, they received an online screening questionnaire including all items regarding the inclusion and exclusions criteria. Those who appeared eligible based on the screening received a mail with participant information form and consent from and a free of charge reply envelope. Researchers called all eligible participants two or three days after sending the information form to elaborate on potential participation and to provide the opportunity the ask questions. Next, eligible participants were invited to sign the consent form and return it in the return envelope. Baseline data collection started as soon as the researchers received the completed consent form. Participants were sent an email explaining study procedures regarding the at-home-measurement kit for the cardiometabolic measurements, the online questionnaires, instructions for the use of a supermarket loyalty card, and, if applicable, instructions for downloading and installation of the step counter app and the coaching app. Instructions referenced a web-based step-by-step guide with pictures, including a video showing the same steps. On the same day of sending this email explaining study procedures, the at-home-measurement kit was sent to the participants home address by mail. The kit consisted of a blood test and a waist circumferences measuring tape, including an instruction letter referencing a web-based instruction video. Four to seven days after sending the athome- measurement kit, participants received two webbased questionnaires. The first questionnaire asked about lifestyle factors and provided opportunity to fill in the results from the at-home waist circumference measurement. The second questionnaire concerned questions on the dietary intake (DHD15-index). Participants not using email received the questionnaires via mail, including a free of charge return envelope. Collected data Table 1 presents an updated version of the study time line and included measurements and changes in collected data and questionnaire items are detailed below. The blood test measures lipid profile and HbA1c concentrations using a finger prick, collecting capillary blood into two small capillary tubes which are sent back to the lab via a medical reply envelope in the mail. Blood samples are collected non-fasted by the participant at home, or if desired by the participant with help from trained research staff during a home visit. Four blood drops are obtained with a single finger prick for the HbA1c test tube, and 16 blood drips for the lipid test tube. Participants are instructed to put their blood sample back in the package designed for medical postal service and ship the test at day of collection. When the outside temperature is 25 degrees of Celsius, the participant is instructed to drop the package at a postal office. Blood samples collected via the at-home measurement kit are analysed by the Amsterdam UMC – VUmc clinical laboratory. HbA1c in the whole blood remains stable at room temperature and the at-home-measurement via the finger prick test of HbA1c is therefore a standard procedure used in the hospital. However, the at-home-measurement of blood lipids was not a standard procedure at study conception. Therefore, the stability of the lipid profile in whole blood kept at room temperature was pilot tested by the laboratory prior to the study. Tubes partly prefilled with heparin were used to secure preservation of the sample for blood plasma analysis. The pilot test was conducted by leaving ten blood samples at room temperature for seven days. Up to day three, the absolute mean change in LDL was deemed acceptable (15% change) as compared to the samples directly analysed at day zero (Table 2). All blood test results were analysed by enzymatic colorimetric test via the Roche/Hitachi Cobas C systems. The lipid test directly measures total cholesterol (TC), HDL-cholesterol and triglycerides (TG). Based on these measurements, the TC/HDL-ratio and the LDL-cholesterol value was calculated following the Friedewald equation. During the baseline measurements, 89% of blood samples were analysed at day 1 after collection, confirming the feasibility of this procedure. Table 3 shows a revised version of all questionnaire items related to secondary outcomes. We have added items relating to perceptions on healthy eating, perceptions during grocery shopping, walking behaviours and social cognitive factors, self-reported walking behaviour and privacy concerns relating to the coaching app. Regarding covariates measured, we have added a question whether participants have been pregnant in the past year considering the waist circumference measurement. Statistical analysis Population baseline characteristics will be described stratified by trial arm, to examine adequate balance between intervention groups and to provide an overview of the study population. Baseline differences between intervention groups will be visually inspected to detect potential clinically relevant differences. Baseline characteristics will be summarised as mean and standard deviation for normally distributed continuous variables, and median and interquartile range for skewed continuous variables. Frequencies and percentages will be presented for each category of categorical variables. Collected data on the DHD15-index scores will be treated as continuous outcome variables. To investigate intervention effects a multilevel analysis (i.e. linear mixed models) will be applied. Analyses will be based on individual participant data, with a random intercept at the subject level and potentially including a random slope for supermarket location. The outcome model will be adjusted for the baseline value in order to take into account the regression to the mean phenomenon. Changes in the secondary outcomes, including all cardiometabolic outcomes, the percentage of healthy food purchase, food decision styles, social cognitive factors, perceptions, and customer satisfaction, will all be treated as continuous outcome variables and analysed following a similar procedure as described at the multilevel analysis for the primary outcome.

Landscape and urban planners, designers, as well as architects, can take up inclusive planning and design processes that acknowledge human needs and dignity, and foster participation in shared decision-making. Underpinning these processes are values of empathy, placation, accessibility, and identity essential to imagining and creating inclusive green cities. This chapter provides a deeper understanding of the different dimensions of an inclusive green city and how social equity is an integral part of any design effort. We begin by exploring our vision and the values necessary for green urban design. A framework for three aspects of equity – recognitional equity, procedural equity, and distributional equity – is presented with selected case studies that serve as evolving good practices for equitable green urban design. From this framework and resulting values, we built on a value-inclusive design canvas and present design principles that planners, designers and architects can adopt as their own.

In previous studies, it has been demonstrated that, similar to general practitioners, veterinarians find it difficult to discuss overweight in dogs. This study aimed to provide insight in the barriers and motivators for veterinarians to discuss overweight in dogs and to compare the results with findings from human medicine. Sub‐hypotheses were postulated based on existing literature to investigate if lack of time, fear of offending clients, or lack of skills were potential barriers, and if feeling responsible and feeling compassion were potential motivators for veterinarians to discuss overweight in dogs. To this end, an online survey (n = 59) was conducted. Furthermore, 15 small animal clinicians working in general practice were interviewed by semi‐structured face‐to‐face interviews. Results from the online survey indicated that veterinarians find it sometimes difficult to discuss overweight in dogs. Veterinarians who responded to the online survey did not experience strong barriers but did make use of motivators (e.g. feeling responsible and feeling compassion) when discussing overweight in dogs. Interestingly, results from the semi‐structured face‐to‐face interviews showed that the responding veterinarians did experience strong barriers, as well as motivators, when discussing overweight in dogs with their clients. The most prominent barrier was customer dissatisfaction, whereas lack of time and lack of skills were also experienced. The most prominent motivator was feeling responsible for animal health and preventive veterinary medicine. These findings were strikingly similar to previous research on discussing childhood overweight by general practitioners. To improve treatment and prevention of overweight in dogs, veterinarians need more communication skills and should be more aware of the motivators that drive their self‐motivation. Improving awareness on overweight and its comorbidities should be a One Health issue.

People are increasingly eating out in restaurants, where meals tend to be higher in calories, less nutritious, and contain more meat. In this paper, we argue that differences in the motivational processes underlying people’s food choices could help to explain why food choices made in restaurants are typically unhealthier and less sustainable than at home. Using online survey data from 301 Dutch participants, we compared the influence of stable personal values and transient food choice motives on the healthiness and sustainability of meals chosen in a hypothetical choice task, which was geared to the home and restaurant consumption contexts. As expected, participants opted for unhealthy and meat-based meals more often in the restaurant than the home context. Conservation values related negatively and self-transcendence values positively to choosing sustainable meals both in the home and in the restaurant context, although the relation with self-transcendence values was significantly weaker in the restaurant context. Also, taste and social eating were considered more important for choosing restaurant meals, while health was a more important motive for food choices at home. Finally, model comparisons revealed that motives were better predictors of healthy meal choices in both contexts, while the influence of values and motives on sustainable meal choices was more similar. In conclusion, the results from the present study enhance our understanding of differences between choosing home and restaurant meals by providing an account of the values and motives associated with the healthiness and sustainability of home and restaurant meal choices.

Self-control is considered a crucial capacity that helps people to achieve important objectives in the face of temptation. However, it is unknown to what extent self-control is a stable disposition that is unaffected by how often people engage in self-control, or more like a skill that develops and grows over time. In the present study, we employed an electronic diary to examine how regular engagement in self-control practice affects self-control capacity. A diverse community sample was followed for 4 months while they engaged in daily practice of a self-chosen self-control behavior. Consistent with our hypothesis, regular practice led to an improvement of medium effect size in self-control capacity. Critically, the level of improvement was dependent on the actual times of practice during a specific interval, and largely independent from beliefs about self-control or self-efficacy. We conclude that “just doing” self-control is the underlying mechanism of increased capacity for self-control. (PsycInfo Database Record (c) 2020 APA, all rights reserved)