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We investigate cross-temporal changes in associations between subscale scores in the four large-scale assessments NLSY, PISA, TIMSS, and PIRLS

Associations between country-level sex differences in large-scale assessment data of maths and science as well as reading and literacy with indicators of national prosperity will be assessed.

The association of brain size and intelligence has been subject to research for a long time (e.g. Rushton & Ankney, 2007). Recent meta-analyses (McDaniel, 2005; Pietschnig et al., 2015; Gignac & Bates, 2017) estimated small to moderate (Pearson) correlations between in vivo brain volume and intelligence. The estimates differ substantial in size. Depending on the used inclusion criteria and meta-analytical methods, the estimates range from r = .24 (Pietschnig et al., 2015) up to r = .39 (Gignac & Bates, 2017). The investigations of possible moderators have also yielded different results. Whereas McDaniel (2005) identified sex and age to be significant moderators, Pietschnig et al. (2015) concluded the opposite. Some moderators have been examined only by one research team and, considering the differences above, need conceptual replication. Ethnicity as a possible moderator has been discussed thoroughly in the literature (e.g. Rushton & Ankney, 2007), but never has been included in a meta-analysis due to lack of data (McDaniel, 2005). Analyses regarding the presence of dissemination bias reached different conclusions as well. Considering these inconsistencies and open questions, this planned study seeks to achieve several goals: (1) Give an additional reasonable estimate of the association of in vivo brain volume and intelligence based on updated data and alternative analysis procedures. (2) Investigate the impact of researcher´s data and analysis decisions (or broadly termed researcher´s degrees of freedom) on the summary effect estimates. (3) Replicate moderator analyses conclusions that were reached unanimously or only have been conducted once (non-clinical vs. patients, correlation of applied intelligence measurement with g). (4) Investigate contradictory conclusions about certain moderators (age, sex). (5) Investigate a potential moderator never analyzed in a meta-analysis on the subject before (ethnicity). (6) Provide information about the extent of bias in the updated data and investigate, why Pietschnig el al. (2015) and Gignac and Bates (2017) reached different conclusions. This will include a replication of a decline effect (Schooler, 2011; Pietschnig et al. 2019) found by Pietschnig et al. (2015). (7) Discuss conclusions about a reasonable effect size estimate range of in vivo brain volume and intelligence. Discuss utility, usability and cost-effectiveness of used methods. In order to achieve these goals, the largest meta-analysis on the subject (Pietschnig et al., 2015) will be updated, expanded, and conducted with additional specification choices. Several sensitivity analyses will be conducted in reference to data and analyses decisions made by the previous meta-analysts. Subsequently all these possible specifications will be included in multiverse, specification curve, and combinatorial analyses (Voracek et al., 2019), to examine inconsistencies regarding the synthesized general effects. Moderators will be investigated with subgroup analyses and meta-regression approaches. A Bayesian meta-analysis will conclude this planned study, exploring the use of non-frequentist methods for the investigation of the association of in vivo brain volume and intelligence.

The link between smoking and suicide has been shown in the general population. People with mental illness have higher incidence and severity in nicotine dependency. Especially in people with psychosis, smoking was linked with higher suicidal behavior (Lasser et al., 2000). The mechanisms behind this phenomena are still yet unclear, this Meta-analysis attempts to widen the body of knowledge by updating a previous Meta-analysis done in 2015 by Sankaranarayanan et al. .

Domain differences in the flynn effect: a preregistered cross-sectional assessment of fluid and crystallized intelligence.

Mental health disorders in parents not only have an impact on their own but also on their children’s lives (Pierce et al., 2020; Rasic et al., 2014). Particularly in the first years of their lives, a secure parent-child-relationship constitutes a basic need, as attachment theory states (Sroufe, 1988). Because of their characteristic symptoms (e.g., having difficulty managing emotions and behavior), people with Borderline personality disorder (BPD) often have unstable and intense interpersonal relationships characterized by alternating between extremes of idealization and devaluation (American Psychiatric Association, 2013). Thus, parents with BPD and their children may be at an increased risk of insecure attachment and consequently of adverse outcomes related to child adjustment compared to healthy parents. Although many studies investigated the negative impact of parental BPD on child adjustment (e.g., Abela et al., 2005; Barnow et al., 2013), a meta-analytic investigation is still lacking. A few years ago, authors conducted two narrative systematic reviews limited to mothers with BPD (as opposed to mothers and fathers; Eyden et al., 2016; Petfield et al., 2015), but did not aggregate individual study results via meta-analysis. Here, we plan to update this review by also including studies since 2016 as well as studies with fathers and by conducting a meta-analysis. In short, the aims of our study are: • Providing an update of the systematic reviews conducted by Eyden et al. (2016) and Petfield et al. (2015) • Conducting a formal meta-analysis on the impact of parental BPD on child adjustment • Providing clinical implications

Creative ability is assumed to help students adapt to the rapidly changing environment, contribute positively to society (OECD, 2019), and correlate with academic achievement (Gajda et al., 2017). Creative ability can be described as the ability to generate ideas that are both, novel and useful (Barron, 1955; see also Runco & Jaeger, 2012). However, creativity is not only a characteristic of, e.g., geniuses and artists but it is the general opinion that everyone has a certain amount of creative potential (Runco, 2003). To be considered indicators of creative potential, factors must serve as antecedents of creative activity and performance and remain relatively stable over time (Karwowski et al., 2019). Examples are divergent thinking (Kim, 2008) and intelligence (Karwowski et al., 2021). However, a person's creative potential does not necessarily lead to creative achievements, as there is evidence that the relationship might be partly explained through creative self-assessments (=CSA) such as creative self-beliefs (Karwowski & Beghetto, 2019). Moreover, it has previously been shown that teachers' perceptions of students' creativity (Karwowski et al., 2015), as well as personality factors such as openness to experience (Karwowski & Lebuda, 2016), significantly predict students' CSA (in the form of creative self-beliefs). Furthermore, representations of creativity are strongly associated with age and cognitive development and creative self-beliefs are not very likely formed in children younger than ten (for an overview see Karwowski & Barbot, 2016). However, the question of the relationship between CSA and the actual creative potential (in the form of divergent thinking = DT; and intelligence = IQ) remains inconclusive. Study aim 1: Therefore, the main goal of this meta-analysis is to investigate whether two indicators of creative potential (i.e., DT and IQ) are associated with CSA by employing a meta-analytical structural equation model following the approach of Cheung (MASEM; Cheung, 2015). Furthermore, we will perform subgroup analyses to investigate the influence of CSA type (i.e., measured through creative self-beliefs, activities, evaluation, and process) and the age of participants (grouped by ISCED into children, adolescents, and adults). Therefore, our study plays a valuable part in understanding how creative self-image is formed and thus, the foundation for creative achievement is laid. Study aim 2: The second aim of our study is to investigate the robustness of the proposed MASEM by applying multiverse and specification curve analyses (Voracek et al., 2019) to all bivariate relationships (DT and IQ, IQ and CSA as well as CSA and DT). This allows us to investigate the influence of various study design variables and meta-analytical decisions simultaneously and will help us understand why different studies might come to different conclusions concerning the relationship between cognitive potential and creative self-assessments (for more information, see point "analysis plan"). Note: Implementing a MASEM requires all the bivariate correlations among all variables (i.e., DT, IQ and CSA) present in the average correlation matrix (Jak & Cheung, 2018). Recently, a meta-analysis focused on the relationship between divergent thinking and intelligence (Gerwig et al., 2021). Therefore, for the link between DT and IQ, we will use and update the already established dataset by Gerwig and colleagues (2021; available under https://osf.io/qamjz/).

A large number of studies have demonstrated that health and even longevity can be predicted by individuals’ cognitive ability (e.g. Gottfredson & Deary, 2004). This research projects aims to further investigate the association of cognitive ability and health; importantly, we intend to examine moderators of this association, such as health behavior and sociodemographic variables. In addition, we plan to carry out subgroup analyses among European nations in order to estimate how systematic differences in health care systems impact the association between intelligence and health. We will use data from the SHARE project, a large-scale survey carried out among residents of all nations of the European Union.

High intelligence is commonly regarded as an unequivocally beneficial feature in humans. Among many other desirable variables, it has been shown to be associated with better physical and mental health outcomes. However, some researchers have found that the prevalence of allergies, asthma, anxiety and other conditions is elevated in populations with exceptionally high intelligence. In the literature, such conditions have been described as physical and psychological overexcitabilities. In this study, we aim to directly replicate and extend the most comprehensive study on the topic, Karpinski, Kinase Kolb, Tetreault, and Borowski (2018). We will investigate the prevalence and underlying mechanisms of physical and psychological overexcitabilities in members of MENSA International, a society that requires members to score in the 98th percentile or above in an IQ test.

Masterarbeit: Der Zusammenhang zwischen Geschwisterreihenfolge und Intelligenz: Eine Metaanalyse Despite the long history of the interest in the relationship between child’s birth order and their intelligence, this topic was never investigated in a meta-analysis. Many studies report results in line with the “Confluence model” from Zajonc (1975) and the “Resource dilution model” from Blake (1981), i.e., a negative correlation between birth order (first born, second born, third born etc.) and intelligence score. Other articles suggest that this correlation is due to family size, which is theoretically described by the “Admixture hypotheses” by Page and Grandon (1979). The aim of this meta-analysis is now to comprehensively analyze these studies, regardless of where they took place and how the sample is composed. Furthermore, other potential moderators such as publication status and publication year are considered. In addition, the correlation between sibling order and intelligence which is controlled for family size is explored.

Brain size and IQ are positively correlated. However, multiple meta-analyses have led to considerable differences in summary effect estimations, thus failing to provide a plausible effect estimate. Here we aim at resolving this issue by providing the largest meta-analysis and systematic review so far of the brain volume and IQ association (86 studies; 454 effect sizes from k = 194 independent samples; N = 26 000+) in three cognitive ability domains (full-scale, verbal, performance IQ). By means of competing meta-analytical approaches as well as combinatorial and specification curve analyses, we show that most reasonable estimates for the brain size and IQ link yield r -values in the mid-0.20s, with the most extreme specifications yielding r s of 0.10 and 0.37. Summary effects appeared to be somewhat inflated due to selective reporting, and cross-temporally decreasing effect sizes indicated a confounding decline effect, with three quarters of the summary effect estimations according to any reasonable specification not exceeding r = 0.26, thus contrasting effect sizes were observed in some prior related, but individual, meta-analytical specifications. Brain size and IQ associations yielded r = 0.24, with the strongest effects observed for more g -loaded tests and in healthy samples that generalize across participant sex and age bands.

Secular increases in population IQ scores throughout the 20th century have been observed with an average increase of three IQ points per decade (Flynn, 1984, 1987; Pietschnig & Voracek, 2015). This phenomenon has been termed the Flynn Effect (Herrnstein & Murray, 1996) and has frequently shown the strongest gains in fluid intelligence (Pietschnig & Voracek, 2015). Individual differences in fluid intelligence have been linked to real world outcomes such as occupational and academic success (Gottfredson, 1997; Neisser et al., 1996). Although classic models characterize intelligence as a unitary construct, some lines of research have suggested that it is probable that intelligence can be understood as a set of subsidiary cognitive functions (Kovacs & Conway, 2016). For instance, fluid intelligence, as measured by reasoning measures, and working memory have shown to be highly correlated in the past (Fukuda et al., 2010). Further investigations of specific aspects of working memory have revealed interactions with attention. Given the interconnectedness of attention and working memory processes, and between working memory processes and fluid intelligence, it is therefore possible that the secular gains witnessed in fluid intelligence over the past century are also reflected in executive functions such as attention. This investigation will contribute to clarifying whether the Flynn Effect also extends to intelligence-related domains and whether a similar trajectory can be observed.

Brain size and IQ are positively correlated. However, multiple meta-analyses have led to considerable differences in summary effect estimations, thus failing to provide a plausible effect estimate. Here we aim at resolving this issue by providing the so far largest meta-analysis and systematic review about the brain volume and IQ association (86 studies; 454 effect sizes from k = 194 independent samples; N = 26 000+) in three cognitive ability domains (full-scale, verbal, performance IQ). By means of competing meta-analytical approaches as well as combinatorial and specification curve analyses, we show that most reasonable estimates for the brain size and IQ link yield r-values in the mid-0.20 s, with the most extreme specifications yielding rs of 0.10 and 0.37. Summary effects appeared to be somewhat inflated due to selective reporting, and cross-temporally decreasing effect sizes indicated a confounding decline effect, with three quarters of the summary effect estimations according to any reasonable specification not exceeding r = 0.26, thus contrasting effect sizes observed in some prior related, but individual, meta-analytical specifications. Brain size and IQ associations yielded r = 0.24, with the strongest effects observed for more g-loaded tests and in healthy samples that generalize across participant sex and age bands.

ObjectivesThe benefits of breastfeeding for cognitive development continue to be hotly debated but are yet to be supported by conclusive empirical evidence.MethodsWe used here a latent growth curve modeling approach to test the association of breastfeeding with IQ growth trajectories, which allows differentiating the variance in the IQ starting point in early life from variance in IQ gains that occur later in childhood through adolescence. Breastfeeding (yes/ no) was modeled as a direct predictor of three IQ latent growth factors (i.e. intercept, slope and quadratic term) and adjusted for the covariates socioeconomic status, mother's age at birth and gestational stage. Data came from the Twins Early Development Study (TEDS), a prospective cohort study of twins born between 1996 and 1994 in the United Kingdom, who were assessed 9 times on IQ between age 2 and 16 years (N = 11,582).ResultsHaving been breastfed was associated with a small yet significant advantage in IQ at age 2 in girls (β = .07, CI 95% from 0.64 to 3.01; N = 3,035) but not in boys (β = .04, CI 95% from -0.14 to 2.41). Having been breastfeeding was neither associated with the other IQ growth factors in girls (slope: β = .02, CI 95% from -0.25 to 0.43; quadratic: β = .01, CI 95% from -0.02 to 0.02) nor in boys (slope: β = .02, CI 95% from -0.30 to 0.47; quadratic: β = -.01, CI 95% from -0.01 to 0.01).ConclusionsBreastfeeding has little benefit for early life intelligence and cognitive growth from toddlerhood through adolescence.