title: Different impressions of other agents obtained through social interaction uniquely modulate dorsal and ventral pathway activities in the social human brain.
abstract: Internal (neuronal) representations in the brain are modified by our experiences, and this phenomenon is not unique to sensory and motor systems. Here, we show that different impressions obtained through social interaction with a variety of agents uniquely modulate activity of dorsal and ventral pathways of the brain network that mediates human social behavior. We scanned brain activity with functional magnetic resonance imaging (fMRI) in 16 healthy volunteers when they performed a simple matching-pennies game with a human, human-like android, mechanical robot, interactive robot, and a computer. Before playing this game in the scanner, participants experienced social interactions with each opponent separately and scored their initial impressions using two questionnaires. We found that the participants perceived opponents in two mental dimensions: one represented "mind-holderness" in which participants attributed anthropomorphic impressions to some of the opponents that had mental functions, while the other dimension represented "mind-readerness" in which participants characterized opponents as intelligent. Interestingly, this "mind-readerness" dimension correlated to participants frequently changing their game tactic to prevent opponents from envisioning their strategy, and this was corroborated by increased entropy during the game. We also found that the two factors separately modulated activity in distinct social brain regions. Specifically, mind-holderness modulated activity in the dorsal aspect of the temporoparietal junction (TPJ) and medial prefrontal and posterior paracingulate cortices, while mind-readerness modulated activity in the ventral aspect of TPJ and the temporal pole. These results clearly demonstrate that activity in social brain networks is modulated through pre-scanning experiences of social interaction with a variety of agents. Furthermore, our findings elucidated the existence of two distinct functional networks in the social human brain. Social interaction with anthropomorphic or intelligent-looking agents may distinctly shape the internal representation of our social brain, which may in turn determine how we behave for various agents that we encounter in our society.
authors.affiliation: Graduate School of Engineering, Osaka University, Japan; Brain Science Institute, Tamagawa University, Japan; CiNet, NICT, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Information Science, Gifu University, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Terada
authors.affiliation: Graduate School of Engineering, Osaka University, Japan; CiNet, NICT, Japan.
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Morita
authors.affiliation: Division of the Humanities and Social Sciences, California Institute of Technology, United States; Graduate School of Letters, Hokkaido University, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: Brain Science Institute, Tamagawa University, Japan; CiNet, NICT, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Haji
authors.affiliation: School of Project Design, Miyagi University, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kozima
authors.affiliation: NAIST, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yoshikawa
authors.affiliation: AIST, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Matsumoto
authors.affiliation: Brain Science Institute, Tamagawa University, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Omori
authors.affiliation: Graduate School of Engineering, Osaka University, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Asada
authors.affiliation: CiNet, NICT, Japan; Graduate School of Medicine, Osaka University, Japan. Electronic address: eiichi.naito@nict.go.jp.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Naito
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology*; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D012919:Social Behavior; D056345:Theory of Mind / Q000502:physiology*; D055815:Young Adult
keywords: Competitive game; Mentalizing; Robot; Social brain; fMRI