Psychological Bulletin

Secondary benefits of family member participation in treatments for childhood disorders: A multilevel meta-analytic review.
Family-based treatments provided around the world for children with mental health, physical health, and developmental disorders often convey secondary mental health benefits to caregivers and siblings who participate in those treatments. Yet, there are no systematic evaluations of these secondary benefits, suggesting that current estimates of the effectiveness of family treatments do not accurately represent the full scope of benefits to participants. In the present study, we use a three-level meta-analysis to summarize the secondary benefits for caregivers (n = 19,895) and siblings (n = 784) who participated in the treatment of a child family member. Results from 128 studies across many countries reveal multiple strengths in the research literature, including frequent use of standardized treatments, random assignment of participants to treatment conditions, and comparison of family-based treatments to usual services. This meta-analysis examines 412 effect sizes and shows that family-based treatments produce small but statistically significant secondary benefits (d = 0.25) compared to individually focused treatments and conditions. In addition, the magnitude of these secondary benefits is relatively consistent across a range of possible moderators, including characteristics of the participants, clinical interventions, study methods, and measures. The only significant moderator of family-based treatments is caregiver gender, such that male caregivers report fewer secondary benefits than do female caregivers. Our findings suggest that there is a pressing need for researchers to routinely measure secondary benefits in studies evaluating family-based treatments of childhood disorders. Furthermore, researchers of these treatments should report family structure, key demographic information (e.g., lesbian, gay, bisexual, transgender, queer or questioning families), and cultural values (e.g., familismo) in their studies. Moreover, administrators, policymakers, and treatment providers would do well to consider the secondary benefits and cost savings of interventions that are delivered to families of children with a wide range of disorders. (PsycInfo Database Record (c) 2025 APA, all rights reserved)
Parents favor daughters: A meta-analysis of gender and other predictors of parental differential treatment.
Decades of research highlight that differential treatment can have negative developmental consequences, particularly for less favored siblings. Despite this robust body of research, less is known about which children in the family tend to be favored or less favored by parents. The present study examined favored treatment as predicted by birth order, gender, temperament, and personality. We also examined whether links were moderated by multiple factors (i.e., parent gender, age, reporter, domain of parenting/favoritism). Multilevel meta-analysis data were collected from 30 peer-reviewed journal articles and dissertations/theses and 14 other databases. In all, the data reflected 19,469 unique participants (Mage = 19.57, SD = 13.92). Results showed that when favoritism was based on autonomy and control, parents tended to favor older siblings. Further, parents reported favoring daughters. Conscientious and agreeable children also received more favored treatment. For conscientious children, favoritism was strongest when based on differences in conflict (i.e., more conscientious children had relatively less conflict with their parents). Parents and clinicians should be aware of which children in a family tend to be favored as a way of recognizing potentially damaging family patterns. (PsycInfo Database Record (c) 2025 APA, all rights reserved)
Reasons to believe: A systematic review and meta-analytic synthesis of the motives associated with conspiracy beliefs.
Belief in conspiracy theories has been linked to harmful consequences for individuals and societies. In an effort to understand and mitigate these effects, researchers have sought to explain the psychological appeal of conspiracy theories. This article presents a wide-ranging systematic review and meta-analysis of the literature on conspiracy beliefs. We analyzed 971 effect sizes from 279 independent studies (Nparticipants = 137,406) to examine the relationships between psychological motives and conspiracy beliefs. Results indicated that these relationships were significant for all three analyzed classes of motivation: epistemic (k = 114, r = .14), existential (k = 121, r = .16), and social motivations related to the individual, relational, and collective selves (k = 100, r = .16). For all motives examined, we observed considerable heterogeneity. Moderation analyses suggest that the relationships were weaker, albeit still significant, when experimental (vs. correlational) designs were used, and differed depending on the conspiracy measure used. We statistically compare the absolute meta-analytic effect size magnitudes against each other and discuss limitations and future avenues for research, including interventions to reduce susceptibility to conspiracy theories. (PsycInfo Database Record (c) 2025 APA, all rights reserved)
Cognitive factors underlying mathematical skills: A systematic review and meta-analysis.
In understanding the nature of mathematical skills, the most influential theories suggest that mathematical cognition draws on different systems: numerical, linguistic, spatial, and general cognitive skills. Studies show that skills in these areas are highly predictive of outcomes in mathematics. Nonetheless, the strength of these relations with mathematical achievement varies, and little is known about the moderators or relative importance of each predictor. Based on 269 concurrent and 174 longitudinal studies comprising 2,696 correlations, this meta-analysis summarizes the evidence on cognitive predictors of mathematical skills in children and adolescents. The results showed that nonsymbolic number skills (often labeled approximate number sense) correlate significantly less with mathematical achievement than symbolic number skills and that various aspects of language relate differently to mathematical outcomes. We observed differential predictive patterns for arithmetic and word problems, and these patterns only partly supported the theory of three pathways—quantitative, linguistic, and spatial—for mathematical skills. Concurrently, nonsymbolic number and phonological skills were weak but exclusive predictors of arithmetic skills, whereas nonverbal intelligence quotient (IQ) predicted word problems only. Only symbolic number skills predicted both arithmetic and word problems concurrently. Longitudinally, symbolic number skills, spatial ability, and nonverbal IQ predicted both arithmetic and word problems, whereas language comprehension was important for word problem solving only. As in the concurrent data, nonsymbolic number skill was a weak longitudinal predictor of arithmetic skills. We conclude that the candidates to target in intervention studies are symbolic number skills and language comprehension. It is uncertain whether the two other important predictors, nonverbal IQ and spatial skills, are actually malleable. (PsycInfo Database Record (c) 2025 APA, all rights reserved)

Psychological Bulletin - Vol 151, Iss 1