Monitoring the reasons why a considerable number of people do not receive recommended vaccinations allows identification of important trends over time, and designing and evaluating strategies to address vaccine hesitancy and increase vaccine uptake. Existing validated measures assessing vaccine hesitancy focus primarily on confidence in vaccines and the system that delivers them. However, empirical and theoretical work has stated that complacency (not perceiving diseases as high risk), constraints (structural and psychological barriers), calculation (engagement in extensive information searching), and aspects pertaining to collective responsibility (willingness to protect others) also play a role in explaining vaccination behavior. The objective was therefore to develop a validated measure of these 5C psychological antecedents of vaccination. Three cross-sectional studies were conducted. Study 1 uses factor analysis to develop an initial scale and assesses the sub-scales’ convergent, discriminant, and concurrent validity (N = 1,445, two German convenience-samples). In Study 2, a sample representative regarding age and gender for the German population (N = 1,003) completed the measure for vaccination in general and for specific vaccinations to assess the potential need for a vaccine-specific wording of items. Study 3 compared the novel scale’s performance with six existing measures of vaccine hesitancy (N = 350, US convenience-sample). As an outcome, a long (15-item) and short (5-item) 5C scale were developed as reliable and valid indicators of confidence, complacency, constraints, calculation, and collective responsibility. The 5C sub-scales correlated with relevant psychological concepts, such as attitude (confidence), perceived personal health status and invulnerability (complacency), self-control (constraints), preference for deliberation (calculation), and communal orientation (collective responsibility), among others. The new scale provided similar results when formulated in a general vs. vaccine-specific way (Study 2). In a comparison of seven measures the 5C scale was constantly among the scales that explained the highest amounts of variance in analyses predicting single vaccinations (between 20% and 40%; Study 3). The present studies are limited to the concurrent validity of the scales. The 5C scale provides a novel tool to monitor psychological antecedents of vaccination and facilitates diagnosis, intervention design and evaluation. Its short version is suitable for field settings and regular global monitoring of relevant antecedents of vaccination.

Even though there are policies in place, and safe and effective vaccines available, almost every country struggles with vaccine hesitancy, that is, a delay in acceptance or refusal of vaccination. Consequently, it is important to understand the determinants of individual vaccination decisions to establish effective strategies to support the success of country-specific public health policies. Vaccine refusal can result from complacency, inconvenience, a lack of confidence, and a rational calculation of pros and cons. Interventions should, therefore, be carefully targeted to focus on the reason for non-vaccination. We suggest that there are several interventions that may be effective for complacent, convenient, and calculating individuals whereas interventions that might be effective for those who lack confidence are scarce. Thus, efforts should be concentrated on motivating the complacent, removing barriers for those for whom vaccination is inconvenient, and adding incentives and additional utility for the calculating. These strategies might be more promising, economic, and effective than convincing those who lack confidence in vaccination.

The use of service robots is on the rise. Characterized by technology autonomy with a physical embodiment, service robots have a higher level of social presence than other service technologies. This research focuses on one specific phenomenon of such social encounters: attribution of responsibility. Study 1 explores potential antecedents driving the attribution of responsibility in encounters with service robots. We derive a research model, which is tested and expanded in three subsequent scenario-based experiments. In Study 2, we find that technology’s autonomy decreases perceived behavioral control over the service robot, which in turn decreases perceived responsibility for positive outcomes but not for negative outcomes. Study 3 indicates that perceived ownership of the service robot accounts for the high responsibility for negative outcomes irrespective of perceived behavioral control. In Study 4, we show that the potential to interrupt the service robots’ autonomy increases perceived behavioral control and perceived responsibility for positive outcomes. Our results propose theoretical implications for responsibility perceptions and practical implications for customer satisfaction with service robots.

During COVID-19, conspiracy theories were intensely discussed in the media. Generally, both believing in conspiracy theories (i.e., explanations for events based on powerholders’ secret arrangements) and being confronted with a conspiracy theory have been found to predict cognition and behavior with negative societal effects, such as low institutional trust. Accordingly, believing in conspiracy theories around COVID-19 should reduce institutional trust, support of governmental regulations and their adoption, and social engagement (e.g., helping members of risk groups). We tested these predictions in a national random sample survey, an experiment, and a longitudinal study ( N _total = 1,213; all studies were preregistered). Indeed, believing in and being confronted with a COVID-19 conspiracy theory decreased institutional trust, support of governmental regulations, adoption of physical distancing, and—to some extent—social engagement. Findings underscore the severe societal effects of conspiracy theories in the context of COVID-19.

Mandatory and voluntary mask policies may have yet unknown social and behavioral consequences related to the effectiveness of the measure, stigmatization, and perceived fairness. Serial cross-sectional data (April 14 to May 26, 2020) from nearly 7,000 German participants demonstrate that implementing a mandatory policy increased actual compliance despite moderate acceptance; mask wearing correlated positively with other protective behaviors. A preregistered experiment ( n = 925) further indicates that a voluntary policy would likely lead to insufficient compliance, would be perceived as less fair, and could intensify stigmatization. A mandatory policy appears to be an effective, fair, and socially responsible solution to curb transmissions of airborne viruses.