Anger and disgust shape judgments of social sanctions across cultures, especially in high individual autonomy societies

When someone violates a social norm, others may think that some sanction would be appropriate. We examine how the experience of emotions like anger and disgust relate to the judged appropriateness of sanctions, in a pre-registered analysis of data from a large-scale study in 56 societies. Across the world, we find that individuals who experience anger and disgust over a norm violation are more likely to endorse confrontation, ostracism and, to a smaller extent, gossip. Moreover, we find that the experience of anger is consistently the strongest predictor of judgments of confrontation, compared to other emotions. Although the link between state-based emotions and judgments may seem universal, its strength varies across countries. Aligned with theoretical predictions, this link is stronger in societies, and among individuals, that place higher value on individual autonomy. Thus, autonomy values may increase the role that emotions play in guiding judgments of social sanctions.

Changes in social norms during the early stages of the COVID-19 pandemic across 43 countries

The emergence of COVID-19 dramatically changed social behavior across societies and contexts. Here we study whether social norms also changed. Specifically, we study this question for cultural tightness (the degree to which societies generally have strong norms), specific social norms (e.g. stealing, hand washing), and norms about enforcement, using survey data from 30,431 respondents in 43 countries recorded before and in the early stages following the emergence of COVID-19. Using variation in disease intensity, we shed light on the mechanisms predicting changes in social norm measures. We find evidence that, after the emergence of the COVID-19 pandemic, hand washing norms increased while tightness and punishing frequency slightly decreased but observe no evidence for a robust change in most other norms. Thus, at least in the short term, our findings suggest that cultures are largely stable to pandemic threats except in those norms, hand washing in this case, that are perceived to be directly relevant to dealing with the collective threat.

Signalling need for care: a neglected functional role of medical treatment

Background and Objectives

While the primary goals of medical treatment are typically to shorten illness or relieve symptoms, we explore the idea that an important additional goal for some patients is to communicate their needs. Drawing on signalling theory, we argue that undergoing treatments can help patients legitimize their illness and thereby enable access to crucial support during convalescence.

Methods and Results

Four pre-registered within-subjects experiments (n = 874) show that participants are more inclined to provide care to people who undergo treatment, especially when that treatment is painful. Results show this incentivizes the use of antibiotic treatments for viral infections as well as drug treatments for mental illness. A cross-sectional study of 194 chronic pain patients shows that those who experience stigma and doubt over the legitimacy of their illness are more likely to accept aversive treatments. Furthermore, two experiments (n = 653) indicate that subtle manipulations of one's sense of social support may increase willingness to accept treatment.

Conclusions and Implications

These results indicate that people make decisions to provide care in part based on the presence or absence of treatment and furthermore that patients' treatment decision-making is informed by the social consequences of their choices. Signalling theory may help explain the surprising longevity of some ineffective and costly medical procedures.

A Taxonomy of Non-honesty in Public Health Communication

This paper discusses the ethics of public health communication. We argue that a number of commonplace tools of public health communication risk qualifying as non-honest and question whether or not using such tools is ethically justified. First, we introduce the concept of honesty and suggest some reasons for thinking it is morally desirable. We then describe a number of common ways in which public health communication presents information about health-promoting interventions. These include the omission of information about the magnitude of benefits people can expect from health-promoting interventions, and failure to report uncertainty associated with the outcomes of interventions. Next we outline some forms of behaviour which are generally recognised by philosophers as being non-honest, including deception, manipulation, and so on. Finally, we suggest that many of the public health communicative practices identified earlier share features with the non-honest behaviours described and suggest this warrants reflection upon whether such non-honesty is justified by the goals of public health communication.

Broad Medical Uncertainty and the ethical obligation for openness

This paper argues that there exists a collective epistemic state of 'Broad Medical Uncertainty' (BMU) regarding the effectiveness of many medical interventions. We outline the features of BMU, and describe some of the main contributing factors. These include flaws in medical research methodologies, bias in publication practices, financial and other conflicts of interest, and features of how evidence is translated into practice. These result in a significant degree of uncertainty regarding the effectiveness of many medical treatments and unduly optimistic beliefs about the benefit/harm profiles of such treatments. We argue for an ethical presumption in favour of openness regarding BMU as part of a 'Corrective Response'. We then consider some objections to this position (the 'Anti-Corrective Response'), including concerns that public honesty about flaws in medical research could undermine trust in healthcare institutions. We suggest that, as it stands, the Anti-Corrective Response is unconvincing.

Disgust sensitivity relates to attitudes toward gay men and lesbian women across 31 nations

Previous work has reported a relation between pathogen-avoidance motivations and prejudice toward various social groups, including gay men and lesbian women. It is currently unknown whether this association is present across cultures, or specific to North America. Analyses of survey data from adult heterosexuals ( N = 11,200) from 31 countries showed a small relation between pathogen disgust sensitivity (an individual-difference measure of pathogen-avoidance motivations) and measures of antigay attitudes. Analyses also showed that pathogen disgust sensitivity relates not only to antipathy toward gay men and lesbians, but also to negativity toward other groups, in particular those associated with violations of traditional sexual norms (e.g., prostitutes). These results suggest that the association between pathogen-avoidance motivations and antigay attitudes is relatively stable across cultures and is a manifestation of a more general relation between pathogen-avoidance motivations and prejudice towards groups associated with sexual norm violations.

Perceptions of the appropriate response to norm violation in 57 societies

Norm enforcement may be important for resolving conflicts and promoting cooperation. However, little is known about how preferred responses to norm violations vary across cultures and across domains. In a preregistered study of 57 countries (using convenience samples of 22,863 students and non-students), we measured perceptions of the appropriateness of various responses to a violation of a cooperative norm and to atypical social behaviors. Our findings highlight both cultural universals and cultural variation. We find a universal negative relation between appropriateness ratings of norm violations and appropriateness ratings of responses in the form of confrontation, social ostracism and gossip. Moreover, we find the country variation in the appropriateness of sanctions to be consistent across different norm violations but not across different sanctions. Specifically, in those countries where use of physical confrontation and social ostracism is rated as less appropriate, gossip is rated as more appropriate.

Little is known about people’s preferred responses to norm violations across countries. Here, in a study of 57 countries, the authors highlight cultural similarities and differences in people’s perception of the appropriateness of norm violations.

Understanding infection prevention behaviour in maternity wards: A mixed-methods analysis of hand hygiene in Zanzibar

RATIONALE

Although women in low- and middle-income countries are increasingly encouraged to give birth at facilities, healthcare-associated infection of both the mother and newborn remain common. An important cause of infection is poor hand hygiene. There is a need to understand how environmental, behavioural, and organisational factors influence hygiene practice.

OBJECTIVE

To understand variations between facilities and between people in hygiene behaviour and to explore potential intervention targets in four labour wards in Zanzibar.

METHODS

Site visits including observation of deliveries and of day-to-day workings of the facilities. Thirty-three semi-structured interviews, totalling more than 46 hours, with birth attendants, orderlies, managerial staff and mothers. Transcribed interviews and observation notes were read and coded by two authors. Themes were developed and analysed in light of existing research.

RESULTS

The physical preconditions for hand hygiene were met more regularly in the two highvolume facilities, where soap, water, gloves were almost always available. However, in all of the facilities, hand hygiene appeared impeded by poor ergonomics, like, for example, physical distance between water taps, gloves, or delivery beds. Recontamination of gloved hands following good hand hygiene was commonly observed, a pattern that the birth attendants attributed to high and unpredictable workload and equipment shortages. Interviews and focus groups suggested that birth attendants typically understood when and why hand hygiene should be implemented, and that they were aware of low handwashing rates among co-workers. In poorer performing facilities, managers were less inclined to visit wards and more likely to perceive hand hygiene as beyond their influence.

CONCLUSIONS

Observations and interviews suggest improvements in the ergonomic design of delivery rooms, including convenient availability of sinks, soap, hand gel, hand towels and gloves, may be a low-cost way to reduce the infection burden from poor hand hygiene.

A Practical Guide to Using Time-and-Motion Methods to Monitor Compliance With Hand Hygiene Guidelines: Experience From Tanzanian Labor Wards

Understanding hand hygiene behaviors is critical in hospitals. We developed the HANDS at birth tool—and provide information on its design and implementation–to capture the complex patterns of health care workers’ hand hygiene including hand rubbing/washing, glove use, and recontamination.

Background: Good-quality evidence on hand hygiene compliance among birth attendants in low-resource labor wards is limited. The World Health Organization Hand Hygiene Observation Form is widely used for directly observing behaviors, but it does not support capturing complex patterns of behavior. We developed the HANDS at Birth tool for direct observational studies of complex patterns of hand rubbing/washing, glove use, recontamination, and their determinants among birth attendants. Understanding these behaviors is particularly critical in wards with variable patient volumes or unpredictable patient complications, such as emergency departments, operating wards, or triage and isolation wards during epidemics. Here we provide detailed information on the design and implementation of the HANDS at Birth tool, with a particular focus on low-resource settings. We developed the HANDS at Birth tool from available guidelines, unstructured observation, and iterative refinement based on consultation with collaborators and pilot results. We designed the tool with WOMBAT software, which supports collecting multidimensional time-and-motion data. Our analysis of the tool’s performance centered on interobserver agreement and convergent validity and the implications of the data structure for data analysis. The HANDS at Birth tool encompasses various hand actions and context-relevant information. Hand actions include procedures relevant during labor and delivery; hand hygiene or glove actions; and other types of touch. During field implementation, we used the tool for continuous observation of the birth attendant. Interobserver agreement was good (kappa range: 0.7–0.9), and the tool showed convergent validity. Using the HANDS at Birth tool is a feasible way to obtain useful information about compliance with hand hygiene procedures. The tool could be used after simple training and allows for collection of reliable information about the complex pattern of hygiene behaviors. Future studies should explore using this tool to observe behavior in labor wards in other settings and in other types of wards.

Birth attendants' hand hygiene compliance in healthcare facilities in low and middle-income countries: a systematic review

Background

With an increasing number of women delivering in healthcare facilities in Low and Middle Income Countries (LMICs), healthcare workers’ hand hygiene compliance on labour wards is pivotal to preventing infections. Currently there are no estimates of how often birth attendants comply with hand hygiene, or of the factors influencing compliance in healthcare facilities in LMICs.

Methods

We conducted a systematic review to investigate the a) level of compliance, b) determinants of compliance and c) interventions to improve hand hygiene during labour and delivery among birth attendants in healthcare facilities of LMICs. We also aimed to assess the quality of the included studies and to report the intra-cluster correlation for studies conducted in multiple facilities.

Results

We obtained 797 results across four databases and reviewed 71 full texts. Of these, fifteen met our inclusion criteria. Overall, the quality of the included studies was particularly compromised by poorly described sampling methods and definitions. Hand hygiene compliance varied substantially across studies from 0 to 100%; however, the heterogeneity in definitions of hand hygiene did not allow us to combine or compare these meaningfully. The five studies with larger sample sizes and clearer definitions estimated compliance before aseptic procedures opportunities, to be low (range: 1–38%). Three studies described two multi-component interventions, both were shown to be feasible.

Conclusions

Hand hygiene compliance was low for studies with larger sample sizes and clear definitions. This poses a substantial challenge to infection prevention during birth in LMICs facilities. We also found that the quality of many studies was suboptimal. Future studies of hand hygiene compliance on the labour ward should be designed with better sampling frames, assess inter-observer agreement, use measures to improve the quality of data collection, and report their hand hygiene definitions clearly.

Using the behaviour change technique taxonomy v1 (BCTTv1) to identify the active ingredients of pharmacist interventions to improve non-hospitalised patient health outcomes

OBJECTIVES

The aim of this study was to identify which behaviour change techniques (BCTs) were present in intervention and control groups of randomised controlled trials (RCTs) included in a Cochrane systematic review.

SETTING

The RCTs included were conducted in community, primary and/or ambulatory-care settings.

PARTICIPANTS

The data set was derived from 86 RCTs from an interim update of the Cochrane review of the effectiveness of pharmacist services on non-hospitalised patient outcomes.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the identification of BCTs scheduled for delivery in intervention and control groups of the RCTs. The secondary outcome measure was to identify which BCTs are not being utilised in intervention and control groups of the RCTs.

RESULTS

The intervention and control groups included 31 and 12 BCTs, respectively. The number of identifiable BCTs/study ranged from 0 to 12 in the intervention groups (mean 3.01 (SD 2.4)) and 0 to 6 in the control groups (mean 0.38 (SD 0.84)). The most commonly identified BCTs in the intervention groups were: instruction on how to perform the behaviour (55%, n=47) (also the most common BCT in control groups); problem solving (29%, n=25); information about health consequences (24%, n=21); social support (practical) (24%, n=21); and social support (unspecified) (23%, n=20) (the second most common BCT in control groups). Thirteen trials had no identifiable BCTs in either group.

CONCLUSION

The pharmacist interventions presented in this study did not use the full range of available BCTs. Furthermore, the reporting of BCTs was incomplete for both intervention and control groups, thereby limiting the utility and reproducibility of the interventions. Future interventions should be designed and reported using relevant taxonomies and checklists for example, BCT taxonomy and TIDieR (the template for intervention description and replication).

Behavioural Determinants of Hand Washing and Glove Recontamination before Aseptic Procedures at Birth: A Time-and-Motion Study and Survey in Zanzibar Labour Wards

Recent research calls for distinguishing whether the failure to comply with World Health Organisation hand hygiene guidelines is driven by omitting to rub/wash hands, or subsequently recontamination of clean hands or gloves prior to a procedure. This study examined the determinants of these two behaviours. Across the 10 highest-volume labour wards in Zanzibar, we observed 103 birth attendants across 779 hand hygiene opportunities before aseptic procedures (time-and-motion methods). They were then interviewed using a structured cross-sectional survey. We used mixed-effect multivariable logistic regressions to investigate the independent association of candidate determinants with hand rubbing/washing and avoiding glove recontamination. After controlling for confounders, we found that availability of single-use material to dry hands (OR:2.9; CI:1.58–5.14), a higher workload (OR:29.4; CI:12.9–67.0), more knowledge about hand hygiene (OR:1.89; CI:1.02–3.49), and an environment with more reminders from colleagues (OR:1.20; CI:0.98–1.46) were associated with more hand rubbing/washing. Only the length of time elapsed since donning gloves (OR:4.5; CI:2.5–8.0) was associated with avoiding glove recontamination. We identified multiple determinants of hand washing/rubbing. Only time elapsed since washing/rubbing was reliably associated with avoiding glove recontamination. In this setting, these two behaviours require different interventions. Future studies should measure them separately.

Do pharmacy intervention reports adequately describe their interventions? A template for intervention description and replication analysis of reports included in a systematic review

INTRODUCTION

Scientific progress and translation of evidence into practice is impeded by poorly described interventions. The Template for Intervention Description and Replication (TIDieR) was developed to specify the minimal intervention elements that should be reported.

OBJECTIVES

(1) To assess the extent to which outpatient pharmacy interventions were adequately reported. (2) To examine the dimension(s) across which reporting quality varies. (3) To examine trial characteristics that predict better reporting.

METHODS

The sample comprised 86 randomised controlled trials identified in a Cochrane review of the effectiveness of pharmacist interventions on patient health outcomes. Duplicate, independent application of a modified 15-item TIDieR checklist was undertaken to assess the intervention reporting. The reporting/non-reporting of TIDieR items was analysed with principal component analysis to evaluate the dimensionality of reporting quality and regression analyses to assess predictors of reporting quality RESULTS: In total, 422 (40%) TIDieR items were fully reported, 395 (38%) were partially reported and 231 (22%) were not reported. A further 242 items were deemed not applicable to the specific trials. Reporting quality loaded on one component which accounted for 26% of the variance in TIDieR scores. More recent trials reported a slightly greater number of TIDieR items (0.07 (95% CI 0.02 to 0.13) additional TIDieR items per year of publication). Trials reported an 0.09 (95% CI 0.04 to 0.14) additional TIDieR items per unit increase in impact factor (IF) of the journal in which the main report was published.

CONCLUSIONS

Most trials lacked adequate intervention reporting. This diminished the applied and scientific value of their research. The standard of intervention reporting is, however, gradually increasing and appears somewhat better in journals with higher IFs. The use of the TIDieR checklist to improve reporting could enhance the utility and replicability of trials, and reduce research waste.

Aversive medical treatments signal a need for support: a mathematical model

Ineffective, aversive and harmful medical treatments are common cross-culturally, historically and today. Using evolutionary game theory, we develop the following model to explain their persistence. Humans are often incapacitated by illness and injury, and are unusually dependent on care from others during convalescence. However, such caregiving is vulnerable to exploitation via illness deception, whereby people feign or exaggerate illness in order to gain access to care. Our model demonstrates that aversive treatments can counter-intuitively increase the range of conditions where caregiving is evolutionarily viable, because only individuals who stand to gain substantially from care will accept the treatment. Thus, contemporary and historical "ineffective" treatments may be solutions to the problem of allocating care to people whose true need is difficult to discern.

The structure and function of pathogen disgust

Researchers have long noted that many of the multiple elicitors of disgust have some relation to infectious disease. There is an emerging consensus that disgust evolved in Animalia to direct the behaviours that reduce risk of infection, so-called 'parasite avoidance theory'. If this is correct, then the disgust motive should be structured in a manner that reflects the ways in which infectious disease can be avoided. In this study, we generated a set of items based on the epidemiology of disease transmission. These were then rated for their capacity to elicit disgust by a large, predominantly North American/UK sample and subjected to factor analysis to identify latent variables. While a number of plausible factor solutions emerged, Velicer's MAP (minimum average partial) test suggested six domains: atypical appearance, lesions, sex, hygiene, food and animals. This structure did not exactly mirror the transmission routes of infections, as we initially predicted, but it may rather reflect distinct kinds of behavioural tasks involved in avoiding disease. This finding makes sense from the perspective of a cognitive system that evolved under selection for a behavioural response to threats from the social and biological environment. We suggest that regularly occurring types of infectious disease problems have produced regularities in the domain structure of pathogen disgust and discuss the implications of these results for understanding the structure, function and measurement of motives such as disgust in humans and other animals.This article is part of the Theo Murphy meeting issue 'Evolution of pathogen and parasite avoidance behaviours'.

Hands washing, glove use, and avoiding recontamination before aseptic procedures at birth: A multicenter time-and-motion study conducted in Zanzibar

BACKGROUND

Our primary objective was to assess hand hygiene (HH) compliance before aseptic procedures among birth attendants in the 10 highest-volume facilities in Zanzibar. We also examined the extent to which recontamination contributes to poor HH. Recording exact recontamination occurrences is not possible using the existing World Health Organization HH audit tool.

METHODS

In this time-and-motion study, 3 trained coders used WOMBATv2 software to record the hand actions of all birth attendants present in the study sites. The percentage compliance and 95% confidence intervals (CIs) for individual behaviors (hand washing/rubbing, avoiding recontamination and glove use) and for behavioral sequences during labor and delivery were calculated.

RESULTS

We observed 104 birth attendants and 781 HH opportunities before aseptic procedures. Compliance with hand rubbing/washing was 24.6% (95% CI, 21.6-27.8). Only 9.6% (95% CI, 7.6-11.9) of birth attendants also donned gloves and avoided recontamination. Half of the time when rubbing/washing or glove donning was performed, hands were recontaminated prior to the aseptic procedure.

CONCLUSIONS

In this study, HH compliance by birth attendants before aseptic procedures was poor. To our knowledge, this is the first study in a low- to middle-income country to show the large contribution to poor HH compliance from hand and glove recontamination before the procedure. Recontamination is an important driver of infection risk from poor HH. It should be understood for the purposes of improvement and therefore included in HH monitoring and interventions.

Pharmacist services for non-hospitalised patients

BACKGROUND

This review focuses on non-dispensing services from pharmacists, i.e. pharmacists in community, primary or ambulatory-care settings, to non-hospitalised patients, and is an update of a previously-published Cochrane Review.

OBJECTIVES

To examine the effect of pharmacists' non-dispensing services on non-hospitalised patient outcomes.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, two other databases and two trial registers in March 2015, together with reference checking and contact with study authors to identify additional studies. We included non-English language publications. We ran top-up searches in January 2018 and have added potentially eligible studies to 'Studies awaiting classification'.

SELECTION CRITERIA

Randomised trials of pharmacist services compared with the delivery of usual care or equivalent/similar services with the same objective delivered by other health professionals.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures of Cochrane and the Effective Practice and Organisation of Care Group. Two review authors independently checked studies for inclusion, extracted data and assessed risks of bias. We evaluated the overall certainty of evidence using GRADE.

MAIN RESULTS

We included 116 trials comprising 111 trials (39,729 participants) comparing pharmacist interventions with usual care and five trials (2122 participants) comparing pharmacist services with services from other healthcare professionals. Of the 116 trials, 76 were included in meta-analyses. The 40 remaining trials were not included in the meta-analyses because they each reported unique outcome measures which could not be combined. Most trials targeted chronic conditions and were conducted in a range of settings, mostly community pharmacies and hospital outpatient clinics, and were mainly but not exclusively conducted in high-income countries. Most trials had a low risk of reporting bias and about 25%-30% were at high risk of bias for performance, detection, and attrition. Selection bias was unclear for about half of the included studies.Compared with usual care, we are uncertain whether pharmacist services reduce the percentage of patients outside the glycated haemoglobin target range (5 trials, N = 558, odds ratio (OR) 0.29, 95% confidence interval (CI) 0.04 to 2.22; very low-certainty evidence). Pharmacist services may reduce the percentage of patients whose blood pressure is outside the target range (18 trials, N = 4107, OR 0.40, 95% CI 0.29 to 0.55; low-certainty evidence) and probably lead to little or no difference in hospital attendance or admissions (14 trials, N = 3631, OR 0.85, 95% CI 0.65 to 1.11; moderate-certainty evidence). Pharmacist services may make little or no difference to adverse drug effects (3 trials, N = 590, OR 1.65, 95% CI 0.84 to 3.24) and may slightly improve physical functioning (7 trials, N = 1329, mean difference (MD) 5.84, 95% CI 1.21 to 10.48; low-certainty evidence). Pharmacist services may make little or no difference to mortality (9 trials, N = 1980, OR 0.79, 95% CI 0.56 to 1.12, low-certaintly evidence).Of the five studies that compared services delivered by pharmacists with other health professionals, no studies evaluated the impact of the intervention on the percentage of patients outside blood pressure or glycated haemoglobin target range, hospital attendance and admission, adverse drug effects, or physical functioning.

AUTHORS' CONCLUSIONS

The results demonstrate that pharmacist services have varying effects on patient outcomes compared with usual care. We found no studies comparing services delivered by pharmacists with other healthcare professionals that evaluated the impact of the intervention on the six main outcome measures. The results need to be interpreted cautiously because there was major heterogeneity in study populations, types of interventions delivered and reported outcomes.There was considerable heterogeneity within many of the meta-analyses, as well as considerable variation in the risks of bias.

Cross-Cultural Differences in Emotional Selection on Transmission of Information

Research on cultural transmission among Americans has established a bias for transmitting stories that have disgusting elements (such as exposure to rats and maggots). Conceived of as a cultural evolutionary force, this phenomenon is one type of emotional selection. In a series of online studies with Americans and Indians we investigate whether there are cultural differences in emotional selection, such that the transmission process favours different kinds of content in different countries. The first study found a bias for disgusting content (rats and maggots) among Americans but not among Indians. Four subsequent studies focused on how country interacts with kind of emotional content (disgusting vs. happy surprises and good news) in reactions to transmission of stories or information. Whereas Indian participants, compared to Americans, tended to be less interested in, and excited by, transmission of stories and news involving common disgust-elicitors (like rats), the opposite pattern held for transmission of happy surprises and good news (e.g., the opening of a new public facility). We discuss various possible explanations and implications.

How feedback biases give ineffective medical treatments a good reputation

BACKGROUND

Medical treatments with no direct effect (like homeopathy) or that cause harm (like bloodletting) are common across cultures and throughout history. How do such treatments spread and persist? Most medical treatments result in a range of outcomes: some people improve while others deteriorate. If the people who improve are more inclined to tell others about their experiences than the people who deteriorate, ineffective or even harmful treatments can maintain a good reputation.

OBJECTIVE

The intent of this study was to test the hypothesis that positive outcomes are overrepresented in online medical product reviews, to examine if this reputational distortion is large enough to bias people's decisions, and to explore the implications of this bias for the cultural evolution of medical treatments.

METHODS

We compared outcomes of weight loss treatments and fertility treatments in clinical trials to outcomes reported in 1901 reviews on Amazon. Then, in a series of experiments, we evaluated people's choice of weight loss diet after reading different reviews. Finally, a mathematical model was used to examine if this bias could result in less effective treatments having a better reputation than more effective treatments.

RESULTS

Data are consistent with the hypothesis that people with better outcomes are more inclined to write reviews. After 6 months on the diet, 93% (64/69) of online reviewers reported a weight loss of 10 kg or more while just 27% (19/71) of clinical trial participants experienced this level of weight change. A similar positive distortion was found in fertility treatment reviews. In a series of experiments, we show that people are more inclined to begin a diet with many positive reviews, than a diet with reviews that are representative of the diet's true effect. A mathematical model of medical cultural evolution shows that the size of the positive distortion critically depends on the shape of the outcome distribution.

CONCLUSIONS

Online reviews overestimate the benefits of medical treatments, probably because people with negative outcomes are less inclined to tell others about their experiences. This bias can enable ineffective medical treatments to maintain a good reputation.

Disgust sensitivity is not associated with health in a rural Bangladeshi sample

Disgust can be considered a psychological arm of the immune system that acts to prevent exposure to infectious agents. High disgust sensitivity is associated with greater behavioral avoidance of disease vectors and thus may reduce infection risk. A cross-sectional survey in rural Bangladesh provided no strong support for this hypothesis. In many species, the expression of pathogen- and predator-avoidance mechanisms is contingent on early life exposure to predators and pathogens. Using childhood health data collected in the 1990s, we examined if adults with more infectious diseases in childhood showed greater adult disgust sensitivity: no support for this association was found. Explanations for these null finding and possible directions for future research are discussed.

Disgust as an adaptive system for disease avoidance behaviour

Disgust is an evolved psychological system for protecting organisms from infection through disease avoidant behaviour. This ‘behavioural immune system’, present in a diverse array of species, exhibits universal features that orchestrate hygienic behaviour in response to cues of risk of contact with pathogens. However, disgust is also a dynamic adaptive system. Individuals show variation in pathogen avoidance associated with psychological traits like having a neurotic personality, as well as a consequence of being in certain physiological states such as pregnancy or infancy. Three specialized learning mechanisms modify the disgust response: the Garcia effect, evaluative conditioning and the law of contagion. Hygiene behaviour is influenced at the group level through social learning heuristics such as ‘copy the frequent’. Finally, group hygiene is extended symbolically to cultural rules about purity and pollution, which create social separations and are enforced as manners. Cooperative hygiene endeavours such as sanitation also reduce pathogen prevalence. Our model allows us to integrate perspectives from psychology, ecology and cultural evolution with those of epidemiology and anthropology. Understanding the nature of disease avoidance psychology at all levels of human organization can inform the design of programmes to improve public health.

Male commuters in north and south England: risk factors for the presence of faecal bacteria on hands

Background

A previous study found that the prevalence of contamination with bacteria of faecal-origin on the hands of men differed across UK cities, with a general trend of increased contamination in northern cities. The aim of this study was to (1) confirm the north-south trend (2) identify causes for the trend.

Methods

Hand swabs from commuters (n = 308) at train stations in 4 cities were tested for the presence of faecal bacteria.

Results

The prevalence of hand contamination with faecal bacteria was again higher in cities in the north compared to the south (5% in London, 4% in Birmingham, 10% in Liverpool and 19% in Newcastle). Contamination risk decreased with age and better personal hygiene (self-reported). Soil contact and shaking hands increased contamination with faecal bacteria. However, in multivariable analysis, none of these factors fully explained the variation in contamination across cities.

Conclusion

The study confirmed the north-south differences in faecal contamination of hands without finding a clear cause for the trend. Faecal contamination of hands was associated with personal hygiene indicators suggesting that microbiological testing may contribute to evaluating hygiene promotion campaigns.

Sensor recorded changes in rates of hand washing with soap in response to the media reports of the H1N1 pandemic in Britain

Objectives To examine how the frequency of information regarding a real disease threat influences hand washing with soap. Design and setting The authors installed wireless devices in highway service station lavatories in England to record the proportion of individuals washing hands with soap from May 2009 to January 2010. Participants Participants were users of men's and women's toilets. Combined there was an average of 6800 participant entrances into the lavatories daily. Primary outcome measure The primary outcome measure is the proportion of soap usage to the number of entries into the lavatories. Results Hand-washing rates were positively related to both H1NI coverage in blogs and the news; however, these relationships were stronger for men than for women. Conclusions Hand washing with soap increases proportionally to the frequency of media key words related to H1N1. Women's hand washing was more strongly associated with incidence of media keywords than men's.