Of differing methods, disputed estimates, and discordant interpretations: The meta-analytical multiverse of brain volume and IQ associations

Autor(en)

Jakob Pietschnig, Daniel Gerdesmann, Michael Zeiler, Martin Voracek

Abstrakt

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 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 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.

Organisation(en)

Institut für Psychologie der Entwicklung und Bildung, Institut für Psychologie der Kognition, Emotion und Methoden

Externe Organisation(en)

Pädagogische Hochschule Freiburg, Medizinische Universität Wien

Journal

Royal Society Open Science

Band

9

Anzahl der Seiten

57

ISSN

2054-5703

DOI

https://doi.org/10.1098/rsos.211621

Publikationsdatum

05-2022

Peer-reviewed

Ja

ÖFOS 2012

501004 Differentielle Psychologie

Schlagwörter

ASJC Scopus Sachgebiete

General

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/b312bfcf-5d41-484f-88ff-be653e486c38