title: Artificial selection on relative brain size reveals a positive genetic correlation between brain size and proactive personality in the guppy.
abstract: Animal personalities range from individuals that are shy, cautious, and easily stressed (a "reactive" personality type) to individuals that are bold, innovative, and quick to learn novel tasks, but also prone to routine formation (a "proactive" personality type). Although personality differences should have important consequences for fitness, their underlying mechanisms remain poorly understood. Here, we investigated how genetic variation in brain size affects personality. We put selection lines of large- and small-brained guppies (Poecilia reticulata), with known differences in cognitive ability, through three standard personality assays. First, we found that large-brained animals were faster to habituate to, and more exploratory in, open field tests. Large-brained females were also bolder. Second, large-brained animals excreted less cortisol in a stressful situation (confinement). Third, large-brained animals were slower to feed from a novel food source, which we interpret as being caused by reduced behavioral flexibility rather than lack of innovation in the large-brained lines. Overall, the results point toward a more proactive personality type in large-brained animals. Thus, this study provides the first experimental evidence linking brain size and personality, an interaction that may affect important fitness-related aspects of ecology such as dispersal and niche exploration.
authors.affiliation: Department for Integrative Biology and Evolution (KLIVV), Veterinary University Vienna, Savoyenstrasse 1A, 1160 Vienna, Austria; Department of Ecology & Genetics/Animal Ecology, Uppsala University, Norbyvägen 18D, SE-75236 Uppsala, Sweden. alexander.kotrschal@ebc.uu.se.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kotrschal
authors.forename: Eva J P
authors.initials: EJ
authors.lastname: Lievens
authors.forename: Josefin
authors.initials: J
authors.lastname: Dahlbom
authors.forename: Andreas
authors.initials: A
authors.lastname: Bundsen
authors.forename: Svetlana
authors.initials: S
authors.lastname: Semenova
authors.forename: Maria
authors.initials: M
authors.lastname: Sundvik
authors.forename: Alexei A
authors.initials: AA
authors.lastname: Maklakov
authors.forename: Svante
authors.initials: S
authors.lastname: Winberg
authors.forename: Pertti
authors.initials: P
authors.lastname: Panula
authors.forename: Niclas
authors.initials: N
authors.lastname: Kolm
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000033:anatomy & histology*; D003071:Cognition; D006854:Hydrocortisone / Q000378:metabolism; D008124:Locomotion; D010551:Personality / Q000235:genetics*; D011036:Poecilia / Q000235:genetics*; D012641:Selection, Genetic; D013315:Stress, Psychological
chemical_list: D006854:Hydrocortisone
keywords: Brain size; Poecilia reticulate; cognition; guppy; personality