Heritability and correlations among learning and inhibitory control traits

• Published in: Behavioral ecology Vol. 31; no. 3; pp. 798 - 806
• Main Authors: Langley, Ellis J G, Adams, Gracie, Beardsworth, Christine E, Dawson, Deborah A, Laker, Philippa R, van Horik, Jayden O, Whiteside, Mark A, Wilson, Alastair J, Madden, Joah R
• Format: Journal Article
• Language: English
• Published: UK Oxford University Press 19.06.2020
• Subjects: Original; pheasant; genetic correlations; cognitive abilities; general intelligence; animal model; heritability
• ISSN: 1045-2249; 1465-7279
• DOI: 10.1093/beheco/araa029

Abstract To understand the evolution of cognitive abilities, we need to understand both how selection acts upon them and their genetic (co)variance structure. Recent work suggests that there are fitness consequences for free-living individuals with particular cognitive abilities. However, our current understanding of the heritability of these abilities is restricted to domesticated species subjected to artificial selection. We investigated genetic variance for, and genetic correlations among four cognitive abilities: inhibitory control, visual and spatial discrimination, and spatial ability, measured on >450 pheasants, Phasianus colchicus, over four generations. Pheasants were reared in captivity but bred from adults that lived in the wild and hence, were subject to selection on survival. Pheasant chicks are precocial and were reared without parents, enabling us to standardize environmental and parental care effects. We constructed a pedigree based on 15 microsatellite loci and implemented animal models to estimate heritability. We found moderate heritabilities for discrimination learning and inhibitory control (h2 = 0.17–0.23) but heritability for spatial ability was low (h2 = 0.09). Genetic correlations among-traits were largely positive but characterized by high uncertainty and were not statistically significant. Principle component analysis of the genetic correlation matrix estimate revealed a leading component that explained 69% of the variation, broadly in line with expectations under a general intelligence model of cognition. However, this pattern was not apparent in the phenotypic correlation structure which was more consistent with a modular view of animal cognition. Our findings highlight that the expression of cognitive traits is influenced by environmental factors which masks the underlying genetic structure. Cognitive traits are crucial determinants of animals’ abilities to adapt to changing environments. For cognitive traits to evolve they must be underpinned by a genetic component. Using quantitative genetics in a nondomesticated system, we show that the basic abilities to inhibit behavior and learn about visual and spatial cues are moderately heritable. This heritability, coupled with fitness consequences of individual differences now demonstrated across several species, highlights the evolutionary potential for basic cognitive abilities.