title: Variant at serotonin transporter gene predicts increased imitation in toddlers: relevance to the human capacity for cumulative culture.
abstract: Cumulative culture ostensibly arises from a set of sociocognitive processes which includes high-fidelity production imitation, prosociality and group identification. The latter processes are facilitated by unconscious imitation or social mimicry. The proximate mechanisms of individual variation in imitation may thus shed light on the evolutionary history of the human capacity for cumulative culture. In humans, a genetic component to variation in the propensity for imitation is likely. A functional length polymorphism in the serotonin transporter gene, the short allele at 5HTTLPR, is associated with heightened responsiveness to the social environment as well as anatomical and activational differences in the brain's imitation circuity. Here, we evaluate whether this polymorphism contributes to variation in production imitation and social mimicry. Toddlers with the short allele at 5HTTLPR exhibit increased social mimicry and increased fidelity of demonstrated novel object manipulations. Thus, the short allele is associated with two forms of imitation that may underlie the human capacity for cumulative culture. The short allele spread relatively recently, possibly due to selection, and its frequency varies dramatically on a global scale. Diverse observations can be unified via conceptualization of 5HTTLPR as influencing the propensity to experience others' emotions, actions and sensations, potentially through the mirror mechanism.
authors.affiliation: Department of Psychological and Brain Sciences, Boston University, 64 Cummington Mall, Boston, MA 02215, USA kari.britt.schroeder@gmail.com.
authors.forename: Kari Britt
authors.identifier: 0000-0002-9730-876X
authors.initials: KB
authors.lastname: Schroeder
authors.affiliation: Department of Social Genetic and Developmental Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, 16 De Crespigny Park, London SE5 8AF, UK.
authors.forename: Philip
authors.initials: P
authors.lastname: Asherson
authors.affiliation: Department of Psychological and Brain Sciences, Boston University, 64 Cummington Mall, Boston, MA 02215, USA.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Blake
authors.affiliation: Department of Psychological Science, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, USA.
authors.forename: Susan K
authors.initials: SK
authors.lastname: Fenstermacher
authors.affiliation: Department of Psychological and Brain Sciences, Boston University, 64 Cummington Mall, Boston, MA 02215, USA.
authors.forename: Kimberly J
authors.initials: KJ
authors.lastname: Saudino
mesh_terms: D002675:Child, Preschool; D005260:Female; D006801:Humans; D007100:Imitative Behavior; D007858:Learning; D008297:Male; D011110:Polymorphism, Genetic; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D012919:Social Behavior; D014427:Twins
chemical_list: C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins
keywords: 5HTTLPR; SLC6A4; cumulative culture; imitation; social learning; social mimicry