Hans IJzerman’s research while affiliated with Institut Universitaire de France and other places

According to the justified true belief (JTB) account of knowledge, people can truly know something only if they have a belief that is both justified and true (i.e., knowledge is JTB). This account was challenged by Gettier, who argued that JTB does not explain knowledge attributions in certain situations, later called “Gettier-type cases,” wherein protagonists are justified in believing something to be true, but their belief was correct only because of luck. Laypeople may not attribute knowledge to protagonists with justified but only luckily true beliefs. Although some research has found evidence for these so-called Gettier intuitions, Turri et al. found no evidence that participants attributed knowledge in a counterfeit-object Gettier-type case differently than in a matched case of JTB. In a large-scale, cross-cultural conceptual replication of Turri and colleagues’ Experiment 1 (N = 4,724) using a within-participants design and three vignettes across 19 geopolitical regions, we did find evidence for Gettier intuitions; participants were 1.86 times more likely to attribute knowledge to protagonists in standard cases of JTB than to protagonists in Gettier-type cases. These results suggest that Gettier intuitions may be detectable across different scenarios and cultural contexts. However, the size of the Gettier intuition effect did vary by vignette, and the Turri et al. vignette produced the smallest effect, which was similar in size to that observed in the original study. Differences across vignettes suggest that epistemic intuitions may also depend on contextual factors unrelated to the criteria of knowledge, such as the characteristics of the protagonist being evaluated.

This Registered Report provides the first test of measurement invariance across time points and estimates of test-retest reliability for the Social Thermoregulation, Risk Avoidance Questionnaire (STRAQ-1, Vergara et al., 2019). The scale was developed and validated to understand the physiological drives underlying interpersonal bonding, measured by four constructs: the desire to socially regulate one’s temperature, the desire to solitary regulate one’s temperature, the sensitivity to higher temperatures, and the desire to avoid risk. Previous studies with large samples across 12 countries showed that the STRAQ-1 has a stable factorial structure, satisfying internal consistencies for the temperature subscales, and expected correlations in its nomological network. However, to date, this instrument has no estimates of test-retest reliability. Throughout four academic years (from 2018 to 2022), N = 183 French student participants took the STRAQ-1 at least two times. Out of the four STRAQ-1 subscales, only two were longitudinally invariant across two-time points. Thus, half of the STRAQ-1 constructs and latent scores were dissimilar and incomparable across time. We then conducted test-retest reliability using Intra Class Correlation coefficient (ICC) for the Social Thermoregulation, Solitary Thermoregulation, High-Temperature Sensitivity, and Risk Avoidance subscales. ICCs estimates were respectively for agreement and consistency: .70, .70 overall moderate to good, .62, .62 overall moderate, .67, .67 overall moderate, and .53, .53 overall poor to moderate, respectively. Our study suggests that test-retest reliability was insufficient for psychological diagnosis, and that future studies should address the problem of low generalizability of the constructs.

Mindfulness witnessed a substantial popularity surge in the past decade, especially as digitally self-administered interventions became available at relatively low costs. Yet, it is uncertain whether they effectively help reduce stress. In a preregistered (OSF https://doi.org/10.17605/OSF.IO/UF4JZ; retrospective registration at ClinicalTrials.gov NCT06308744) multi-site study (nsites = 37, nparticipants = 2,239, 70.4% women, Mage = 22.4, s.d.age = 10.1, all fluent English speakers), we experimentally tested whether four single, standalone mindfulness exercises effectively reduced stress, using Bayesian mixed-effects models. All exercises proved to be more efficacious than the active control. We observed a mean difference of 0.27 (d = −0.56; 95% confidence interval, −0.43 to −0.69) between the control condition (M = 1.95, s.d. = 0.50) and the condition with the largest stress reduction (body scan: M = 1.68, s.d. = 0.46). Our findings suggest that mindfulness may be beneficial for reducing self-reported short-term stress for English speakers from higher-income countries.

Loneliness has been associated with a number of detrimental effects for individuals and societies, making it a priority for monitoring across the European Union. While many loneliness measures currently exist, notable gaps exist regarding knowledge of their psychometric structure, reliability, comparability, and validity, particularly as it pertains to their suitability for EU-wide population surveys. Relying on data from the EU Loneliness Survey representing the 27 EU member states (N=25,646), we examined the factor structure, internal consistency, measurement invariance, and construct validity of the six-item De Jong Gierveld Loneliness Scale (DJGLS-6), the three-item UCLA Loneliness Scale (T-ILS), and a single-item measure of loneliness. Following a process of pre-registered analyses in an exploratory fold, followed by pre-registered confirmatory analyses testing the model sharpened in the exploratory fold, we found (a) the DJGLS-6 to show [poor/acceptable/very good] fit to a [one/two] factor structure for XX countries, [sufficient/insufficient] internal consistency for XX countries, [measurement invariance property described here], and [sufficient/insufficient] construct validity for XX countries, (b) the T-ILS to show [poor/acceptable/very good] fit to a one factor structure for XX countries, [sufficient/insufficient] internal consistency for XX countries, [measurement invariance property described here], and [sufficient/insufficient] construct validity for XX countries, and (c) the single-item measure of loneliness to show [sufficient/insufficient] construct validity for XX countries. Overall, the evidence suggests [based on the results described above, we will conclude on the suitability of the DJGLS-6, T-ILS, and single-item measure for monitoring loneliness in the European Union].

The authors use infrared thermography measurements of skin temperature to non-invasively assess the heat production of Brown Adipose Tissue (BAT). In species other than humans, BAT has been linked to maternal care, and may thus be crucial for understanding differences in attachment security. Whereas early BAT research measured its relative presence in the human body through radioactive tracers, researchers have recently used infrared thermography measurement of skin temperature in cold conditions to study BAT thermogenesis outside of medical facilities. Infrared thermography relies on comparing skin temperature in the supraclavicular region (where a BAT depot is located) with skin temperature in the sternal region (which contains no BAT depots) in cold conditions, when the supraclavicular BAT depot produces heat. We replicated an infrared thermography protocol, which previously reported an increase of 0.2 °C in supraclavicular (vs. sternal) skin temperature in cold (vs. control) conditions in only 7 adults, which probably led to overestimation of the effect. With a much larger sample size (N = 94 young adults) and a similar protocol, we did not find any significant variation in relative, Cohen’s d = 0.10, 95% CI [-0.31, 0.50], or absolute supraclavicular skin temperature, Cohen’s d = 0.11, 95% CI [-0.30, 0.52]. Using conditional random forests, we also excluded a variety of alternative explanations for why the method failed to achieve an effect. This protocol of infrared thermography cannot measure BAT thermogenesis and is thus not recommended for future studies to study individual differences in attachment.

Social connection is vital to health and longevity. To date, a plethora of instruments exists to measure social connection, assessing a variety of aspects of social connection like loneliness, social isolation, or social support. For comparability and consistency of the published literature and for policy recommendations, consolidation and evaluation of the quality of measures is crucial. To answer the call for comparability, in Study 1a, we conducted a systematic review to create a database of social connection measures (N=xx) for its structure (N=xx), function (N=xx), and quality components (N=xx), spanning [YEAR] to [YEAR]; after which, in Study 1b, we assessed the heterogeneity of these existing measures through an item-content analysis relying both on human coders, as well as ChatGPT. We identified a total of XX item categories (XX for structure, XX for function, and XX for quality components) with a Jaccard index of XX for structure, XX for function, and XX for quality components. To answer the call for quality assessment, in Study 2a, we conducted a second systematic review on the measures found in Study 1a, creating a database documenting overall validity evidence. In Study 2b, we then evaluated the measurement properties using the COnsensus-based Standards for the Selection of health Measurement Instruments. We found the measurement properties to be [sufficient / insufficient / inconsistent / indeterminate], [sufficient / insufficient / inconsistent / indeterminate], and [sufficient / insufficient / inconsistent / indeterminate]; with [high/moderate/low/very low], [high/moderate/low/very low], and [high/moderate/low/very low] quality of evidence for the structure, function, and quality components, respectively. Finally, we identified the country of origin of the measures and the population groups with which they were developed, using data from Study 1a. Most of the measures were developed in [country name] (XX%) and for [add population characteristics] (XX%). [Overall conclusion].

Authors rely on a range of devices and techniques to attract and maintain the interest of readers, and to convince them of the merits of the author’s point of view. However, when writing a scientific article, authors must use these ‘persuasive communication devices’ carefully. In particular, they must be explicit about the limitations of their work, avoid obfuscation, and resist the temptation to oversell their results. Here we discuss a list of persuasive communication devices and we encourage authors, as well as reviewers and editors, to think carefully about their use.

In this meta-analysis, the authors investigated whether being in nature and emotional social support are reliable strategies to downregulate stress. We retrieved all the relevant articles that investigated a connection between one of these two strategies and stress. For being in nature we found 54 effects reported in 16 papers (total N = 1,697, MdnN = 52.5), while for emotional social support we found 18 effects reported in 13 papers (total N = 3,787, MdnN = 186). Although we initially found an effect for being in nature and emotional social support on stress (Hedges’ g = -.42; Hedges’ g = -.14, respectively), the effect only held for being in nature after applying our main publication bias correction technique (Hedges’ g = -.60). The emotional social support literature also had a high risk of bias. Although the being-in-nature literature was moderately powered (.72) to detect effects of Cohen’s d = .50 or larger, the risk of bias was considerable, and the reporting contained numerous statistical reporting errors.

Authors rely on a range of devices and techniques to attract and maintain the interest of readers, and to convince them of the merits of the author’s point of view. However, when writing a scientific article, authors must use these ‘persuasive communication devices’ carefully. In particular, they must be explicit about the limitations of their work, avoid obfuscation, and resist the temptation to oversell their results. Here we discuss a list of persuasive communication devices and we encourage authors, as well as reviewers and editors, to think carefully about their use.