The Myth of the Need for Diversity Among Subjects in Theory-Testing Research: Comments on "Racial Inequality in Psychological Research" by Roberts et al. (2020).

Roberts and colleagues focus on two aspects of racial inequality in psychological research, namely an alleged underrepresentation of racial minorities and the effects attributed to this state of affairs. My comment focuses only on one aspect, namely the assumed consequences of the lack of diversity in subject populations. Representativeness of samples is essential in survey research or applied research that examines whether a particular intervention will work for a particular population. Representativeness or diversity is not necessary in theory-testing research, where we attempt to establish laws of causality. Because theories typically apply to all of humanity, all members of humanity (even American undergraduates) are suitable for assessing the validity of theoretical hypotheses. Admittedly, the assumption that a theory applies to all of humanity is also a hypothesis that can be tested. However, to test it, we need theoretical hypotheses about specific moderating variables. Supporting a theory with a racially diverse sample does not make conclusions more valid than support from a nondiverse sample. In fact, cause-effect conclusions based on a diverse sample might not be valid for any member of that sample.

Passion for guns and beliefs in a dangerous world: An examination of defensive gun ownership.

This research examines the notion of defensive gun ownership using the Dualistic Model of Passion. We hypothesized that an obsessive (vs. harmonious) passion for guns would be associated with a belief in a dangerous world (BDW). We expected this relationship to intensify in threatening contexts, leading to a more expansive view on defensive gun ownership. We tested this hypothesis across three threat contexts: a gun-control message (Study 1, N = 342), a live shooting simulation (Study 2, N = 398), and the aftermath of the Christchurch mass shootings (Study 3, N = 314). In the experimental Study 1, exposure to a gun-control message increased the intention to purchase guns among those with an obsessive passion (OP) for guns. Study 2 revealed that BDW mediated the relationship between OP and assertive modes of protection, the desire to purchase high-stopping-power guns, and anti-Black racial bias in a shooting task. Study 3 showed that knowledge of the Christchurch attack intensified the link between OP and BDW, leading to increased support for gun access, a willingness to act as a citizen-protector, and prejudice against Muslims. Comprehending these dynamics can assist policymakers in crafting messaging campaigns for firearm regulation and public safety measures that are more effective.

Is the energy balance explanation of the obesity epidemic wrong?

There is a striking discrepancy in both U.S and the U.K data between obesity rates, which are increasing, and self-reported food consumption rates, which are decreasing. There are two possible explanations for this discrepancy, namely that the widely accepted energy balance interpretation of obesity is wrong or that food consumption data are somehow biased. In a comment entitled "Obesity-an unexplained epidemic", Mozaffarian (2022) challenged the Energy Balance Model (EBM) and argued for a need to replace it with a novel biological theory. This challenge is premature, because there are psychological explanations for this discrepancy, namely that individuals with overweight and obesity underreport their food consumption and that this tendency has increased in recent years. To support these hypotheses, U.S and U.K data are reviewed that used the Doubly Labelled Water method (DLW), which is the gold standard for estimating energy expenditure. Such studies find not only consistent evidence of underreporting, but also that the discrepancy between measured energy expenditure and reported calorie consumption increased over time. Two psychological explanations for this pattern are discussed.

Could implementation intentions improve the efficacy of behavioral weight-loss treatment?

Although behavioral weight loss treatment can result in health benefits, the effects on weight loss are generally disappointing, with lost weight regained within a few years. Because these problems appear to be due to a failure to execute the strong weight control intentions formed during treatment, the use of implementation intentions is suggested to bridge that intention-behavior gap. In contrast to behavioral intentions, implementation intentions specify the situation in which the behavior should be enacted. Although implementation intentions have generally been very effective in increasing the likelihood of goal attainment for a wide range of behaviors, results with regard to eating have been mixed. Especially disappointing have been the findings of a large study that added implementation intentions to a clinical weight loss treatment and found no effects either on weight loss or on weight loss maintenance (Knäuper et al., 2018). I argue that this failure is due to the use of implementation intentions that target specific eating behaviors. According to the goal conflict model of eating, implementation intentions are most effective if they prime the weight control goal; implementation intentions targeting specific behaviors do not reliably do that. I review evidence that the implementation intention to think of dieting when confronted with palatable food items primes weight control thoughts. It also reduces eating of primed foods and even result in weight loss.

Suicide in Switzerland: why gun ownership can be deadly.

There is a great deal of empirical evidence that owning a firearm increases the risk of dying from suicide. Most suicides are impulsive. Nearly 50% of survivors of suicide attempts report that they took less than 10 minutes between the decision to die and their suicide attempt. The great majority of these suicide survivors never make another attempt and die of natural causes. Because nearly 90% of firearm suicide attempts have a deadly outcome, gun owners are unlikely to have such a second chance. These impulsive suicide attempts are typically carried out with the means at hand. Swiss men have much higher firearm suicide rates than men in other European countries and this excess is likely to be due to their easy access to guns, because army conscripts have to keep their guns at home. When the number of conscripts was nearly halved in 2003/4 as a result of the Swiss Army Reform XXI, the number of army-issued firearms was reduced by an estimated 20%. An analysis of suicide rates before and after the reform indicated that male (but not female) suicide rates decreased by 8%, with no evidence of substitution with other means of suicide. If the army would require that the remaining half of conscripts had to keep their weapons at their barracks rather than at home, a further decrease in male suicide rates could be expected.

Why some people do not get vaccinated against COVID-19: Social-cognitive determinants of vaccination behavior.

It is puzzling that a sizeable percentage of people refuse to get vaccinated against COVID-19. This study aimed to examine social psychological factors influencing their vaccine hesitancy. This longitudinal study traced a cohort of 2663 individuals in 25 countries from the time before COVID-19 vaccines became available (March 2020) to July 2021, when vaccination was widely available. Multilevel logistic regressions were used to examine determinants of actual COVID-19 vaccination behavior by July 2021, with country-level intercept as random effect. Of the 2663 participants, 2186 (82.1%) had been vaccinated by July 2021. Participants' attitude toward COVID-19 vaccines was the strongest predictor of both vaccination intention and subsequent vaccination behavior (p < .001). Perceived risk of getting infected and perceived personal disturbance of infection were also associated with higher likelihood of getting vaccinated (p < .001). However, religiosity, right-wing political orientation, conspiracy beliefs, and low trust in government regarding COVID-19 were negative predictors of vaccination intention and behavior (p < .05). Our findings highlight the importance of attitude toward COVID-19 vaccines and also suggest that certain life-long held convictions that predate the pandemic make people distrustful of their government and likely to accept conspiracy beliefs and therefore less likely to adopt the vaccination behavior.

Using machine learning to identify important predictors of COVID-19 infection prevention behaviors during the early phase of the pandemic.

Before vaccines for coronavirus disease 2019 (COVID-19) became available, a set of infection-prevention behaviors constituted the primary means to mitigate the virus spread. Our study aimed to identify important predictors of this set of behaviors. Whereas social and health psychological theories suggest a limited set of predictors, machine-learning analyses can identify correlates from a larger pool of candidate predictors. We used random forests to rank 115 candidate correlates of infection-prevention behavior in 56,072 participants across 28 countries, administered in March to May 2020. The machine-learning model predicted 52% of the variance in infection-prevention behavior in a separate test sample-exceeding the performance of psychological models of health behavior. Results indicated the two most important predictors related to individual-level injunctive norms. Illustrating how data-driven methods can complement theory, some of the most important predictors were not derived from theories of health behavior-and some theoretically derived predictors were relatively unimportant.

Predictors of adherence to public health behaviors for fighting COVID-19 derived from longitudinal data.

The present paper examines longitudinally how subjective perceptions about COVID-19, one's community, and the government predict adherence to public health measures to reduce the spread of the virus. Using an international survey (N = 3040), we test how infection risk perception, trust in the governmental response and communications about COVID-19, conspiracy beliefs, social norms on distancing, tightness of culture, and community punishment predict various containment-related attitudes and behavior. Autoregressive analyses indicate that, at the personal level, personal hygiene behavior was predicted by personal infection risk perception. At social level, social distancing behaviors such as abstaining from face-to-face contact were predicted by perceived social norms. Support for behavioral mandates was predicted by confidence in the government and cultural tightness, whereas support for anti-lockdown protests was predicted by (lower) perceived clarity of communication about the virus. Results are discussed in light of policy implications and creating effective interventions.

Correction: Politicization of COVID-19 health-protective behaviors in the United States: Longitudinal and cross-national evidence.

[This corrects the article DOI: 10.1371/journal.pone.0256740.].

Politicization of COVID-19 health-protective behaviors in the United States: Longitudinal and cross-national evidence.

During the initial phase of the COVID-19 pandemic, U.S. conservative politicians and the media downplayed the risk of both contracting COVID-19 and the effectiveness of recommended health behaviors. Health behavior theories suggest perceived vulnerability to a health threat and perceived effectiveness of recommended health-protective behaviors determine motivation to follow recommendations. Accordingly, we predicted that-as a result of politicization of the pandemic-politically conservative Americans would be less likely to enact recommended health-protective behaviors. In two longitudinal studies of U.S. residents, political conservatism was inversely associated with perceived health risk and adoption of health-protective behaviors over time. The effects of political orientation on health-protective behaviors were mediated by perceived risk of infection, perceived severity of infection, and perceived effectiveness of the health-protective behaviors. In a global cross-national analysis, effects were stronger in the U.S. (N = 10,923) than in an international sample (total N = 51,986), highlighting the increased and overt politicization of health behaviors in the U.S.

Biased hate crime perceptions can reveal supremacist sympathies.

People may be sympathetic to violent extremism when it serves their own interests. Such support may manifest itself via biased recognition of hate crimes. Psychological surveys were conducted in the wakes of mass shootings in the United States, New Zealand, and the Netherlands (total n = 2,332), to test whether factors that typically predict endorsement of violent extremism also predict biased hate crime perceptions. Path analyses indicated a consistent pattern of motivated judgment: hate crime perceptions were directly biased by prejudicial attitudes and indirectly biased by an aggrieved sense of disempowerment and White/Christian nationalism. After the shooting at a synagogue in Pittsburgh, Pennsylvania, disempowerment-fueled anti-Semitism predicted lower perceptions that the gunman was motivated by hatred and prejudice (study 1). After the shootings that occurred at two mosques in Christchurch, New Zealand, disempowerment-fueled Islamoprejudice similarly predicted lower hate crime perceptions (study 2a). Conversely, after the tram shooting in Utrecht, Netherlands (which was perpetrated by a Turkish-born immigrant), disempowerment-fueled Islamoprejudice predicted higher hate crime perceptions (study 2b). Finally, after the Walmart shooting in El Paso, Texas, hate crime perceptions were specifically biased by an ethnonationalist view of Hispanic immigrants as a symbolic (rather than realistic) threat to America; that is, disempowered individuals deemphasized likely hate crimes due to symbolic concerns about cultural supremacy rather than material concerns about jobs or crime (study 3). Altogether, biased hate crime perceptions can be purposive and reveal supremacist sympathies.

Frustration-affirmation? Thwarted goals motivate compliance with social norms for violence and nonviolence.

When thwarted goals increase endorsement of violence, it may not always reflect antisocial tendencies or some breakdown of self-regulation per se; such responses can also reflect an active process of self-regulation, whose purpose is to comply with the norms of one's social environment. In the present experiments (total N = 2,145), the causal link between thwarted goals and endorsement of violent means (guns and war) was found to be contingent on perceptions that violence is normatively valued. Experiments 1-3 establish that thwarted goals increase endorsement of violence primarily among U.S. adults of a lower educational background and/or men who endorse a masculine honor culture. Experiment 4 manipulates the perceived normative consensus of college educated Americans, and demonstrates that thwarted goals increase college educated Americans' endorsement of whatever norm is salient: prowar or antiwar. Generalizing the model beyond violent means, Experiment 5 demonstrates that goal-thwarted Europeans report increased willingness to volunteer for refugee support activities if they perceive strong social norms to volunteer. Altogether, these findings support a frustration-affirmation model rather than frustration-aggression, whereby thwarted goals increase compliance with perceived norms for behavior, which can increase endorsement of violent means such as guns and war, but also nonviolent charitable actions. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Mass shootings and the salience of guns as means of compensation for thwarted goals.

Between 2016 and 2017, Americans suffered 3 of the deadliest mass shootings in modern history by a lone gunman: the Orlando nightclub shooting, the Las Vegas strip shooting, and the Texas church shooting. We studied American gun owners in the wakes of these tragedies, theorizing that a byproduct of the salience of mass shootings is to increase the salience of guns as means of individual empowerment and significance. We hypothesized that this increase in salience would be especially relevant in the context of thwarted goals, because such individuals may be seeking a compensatory means to interact more effectively with their environment. In 4 studies of U.S. gun owners (N = 2,442), we tested whether mass shooting salience interacted with thwarted goals to predict justification to shoot suspected criminals, as well as ideas about armed vigilantism and perceptions that guns are means of empowerment. The thwarting of goals was either experimentally induced via failure on an achievement task (Study 1), or measured via perceptions of disempowerment in society (Studies 2-4). Mass shooting salience was measured via perceptions of mass shooting threat, as well as temporal proximity and social proximity to specific mass shooting events. Across studies, results indicated an interaction between thwarted goals and mass shooting salience; temporal proximity yielded mixed results. Altogether, thwarted goals motivate people to seek effectiveness and mattering, and guns are more likely to be perceived as means to such ends when mass shootings loom large in the mind. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

What have we learned? What can we learn?

We advocate that replications should be an integral part of the scientific discourse and provide insights about the conditions under which an effect occurs. By themselves, mere nonreplications are not informative about the "truth" of an effect. As a consequence, the mechanistic continuation of multilab replications should be replaced by diagnostic studies providing insights about the underlying causes and mechanisms.

Is It a Dangerous World Out There? The Motivational Bases of American Gun Ownership.

Americans are the world's best armed citizens and public polling suggests protection/self-defense is their main reason for gun ownership. However, there is virtually no psychological research on gun ownership. The present article develops the first psychological process model of defensive gun ownership-specifically, a two-component model that considers both the antecedents and consequences of owning a gun for protection/self-defense. We demonstrate that different levels of threat construal-the specific perceived threat of assault and a diffuse threat of a dangerous world-independently predict handgun ownership; we also show how utility judgments can explain the motivated reasoning that drives beliefs about gun rights. We tested our model in two independent samples of gun owners (total N = 899), from just before and after the Orlando mass shooting. This study illustrates how social-cognitive theories can help explain what motivates Americans to own handguns and advocate for broad rights to carry and use them.

The impact of the Orlando mass shooting on fear of victimization and gun-purchasing intentions: Not what one might expect.

Mass public shootings are typically followed by a spike in gun sales as well as calls for stricter gun control laws. What remains unclear is whether the spike in gun sales is motivated by increased threat perceptions or by concerns about gun control, or whether the sales are mainly driven by non-owners purchasing guns or gun owners adding to their collection. Two surveys of gun owners and non-owners, conducted immediately before and after the Orlando shooting, allowed us to assess its impact on threat perceptions and on gun-purchasing intentions. Although there was a minor impact on threat perceptions of non-owners, neither group reported any increased gun-purchasing intentions or an increased need of a gun for protection and self-defense. We suggest that these responses are representative for the majority of Americans and, therefore, people who are influenced by mass shootings to buy guns are probably an atypical minority.

The impact of bereaved parents' perceived grief similarity on relationship satisfaction.

The present research focused on bereaved parents' perceived grief similarity, and aimed to investigate the concurrent and longitudinal effects of the perceptions that the partner has less, equal, or more grief intensity than oneself on relationship satisfaction. Participants of our longitudinal study were 229 heterosexual bereaved Dutch couples who completed questionnaires 6, 13, and 20 months after the loss of their child. Average age of participants was 40.7 (SD = 9.5). Across 3 study waves, participants' perceived grief similarity and relationship satisfaction were assessed. To control for their effects, own grief level, child's gender, expectedness of loss, parent's age, parent's gender, and time were also included in the analyses. Consistent with the hypotheses, cross-sectional results revealed that bereaved parents who perceived dissimilar levels of grief (less or more grief) had lower relationship satisfaction than bereaved parents who perceived similar levels of grief. This effect remained significant controlling for the effects of possible confounding variables and actual similarity in grief between partners. We also found that perceived grief similarity at the first study wave was related to the highest level of relationship satisfaction at the second study wave. Moreover, results showed that perceived grief similarity was associated with a higher level in partner's relationship satisfaction. Results are discussed considering the comparison and similarity in grief across bereaved partners after child loss. (PsycINFO Database Record

Why Good Teaching Evaluations May Reward Bad Teaching: On Grade Inflation and Other Unintended Consequences of Student Evaluations.

In this article, I address the paradox that university grade point averages have increased for decades, whereas the time students invest in their studies has decreased. I argue that one major contributor to this paradox is grading leniency, encouraged by the practice of university administrators to base important personnel decisions on student evaluations of teaching. Grading leniency creates strong incentives for instructors to teach in ways that would result in good student evaluations. Because many instructors believe that the average student prefers courses that are entertaining, require little work, and result in high grades, they feel under pressure to conform to those expectations. Evidence is presented that the positive association between student grades and their evaluation of teaching reflects a bias rather than teaching effectiveness. If good teaching evaluations reflected improved student learning due to effective teaching, they should be positively related to the grades received in subsequent courses that build on knowledge gained in the previous course. Findings that teaching evaluations of concurrent courses, though positively correlated with concurrent grades, are negatively related to student performance in subsequent courses are more consistent with the assumption that concurrent evaluations are the result of lenient grading rather than effective teaching. Policy implications are discussed.

Internet-Based Exposure and Behavioral Activation for Complicated Grief and Rumination: A Randomized Controlled Trial.

This study examined the effectiveness and feasibility of therapist-guided Internet-delivered exposure (EX) and behavioral activation (BA) for complicated grief and rumination. Forty-seven bereaved individuals with elevated levels of complicated grief and grief rumination were randomly assigned to three conditions: EX (N=18), BA (N=17), or a waiting-list (N=12). Treatment groups received 6 homework assignments over 6 to 8weeks. Intention-to-treat analyses showed that EX reduced complicated grief, posttraumatic stress, depression, grief rumination, and brooding levels relative to the control group at posttreatment (d=0.7-1.2). BA lowered complicated grief, posttraumatic stress, and grief rumination levels at posttreatment (d=0.8-0.9). At 3-month follow-up, effects of EX were maintained on complicated grief and grief rumination (d=0.6-1.2), and for BA on complicated grief, posttraumatic stress, and grief rumination (d=0.8-0.9). EX reduced depression more strongly than BA (d=0.6). Completers analyses corroborated results for EX, and partially those for BA, but no group differences were detected. BA suffered from high dropout (59%), relative to EX (33%) and the waiting-list (17%). Feasibility appeared higher for EX than BA. Results supported potential applicability of online exposure but not behavioral activation to decrease complicated grief and rumination.