Izawa, Eiichi



Faculty of Letters, Department of Humanities and Social Science (Human Relations) (Mita)



Related Websites

Career 【 Display / hide

  • 2002.04

    JSPS doctal research fellow/ Graduate School of Bioagricultural Sciences, Naogya University

  • 2004.04

    JSPS Post-doctal research fellow/ Graduate School of Human relations, Keio University

  • 2006.01

    慶應義塾大学文学研究科 准教授(有期)(魅力ある大学院教育イニシアティブ)

  • 2008.04

    慶應義塾大学社会学研究科 准教授(有期)(人文グローバルCOE”論理と感性に関する先端的教育研究拠点”)

  • 2012.04

    慶應義塾大学 論理と感性のグローバル研究センター, 共同研究員

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Academic Background 【 Display / hide

  • 1999.03

    Nagoya University, School of Science, Department of Physics

    University, Graduated

  • 1999.04

    Nagoya University, 大学院生命農学研究科, 生物機構・機能科学専攻

    Graduate School, Completed, Master's course

  • 2001.04

    Nagoya University, Bioagricultural Sciences, Biological Mechanisms and Functions

    Graduate School, Completed, Doctoral course

Academic Degrees 【 Display / hide

  • 博士(農学), Nagoya University, Coursework, 2003.03


Research Areas 【 Display / hide

  • Humanities & Social Sciences / Experimental psychology (Animal Psychology)

  • Neuroethology


Books 【 Display / hide

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Papers 【 Display / hide

  • Social encounters produce different autonomic response between dominants and subordinates in crows

    Takeda K., Takahashi N., Izawa E.I.

    Royal Society Open Science (Royal Society Open Science)  9 ( 10 )  2022.10

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    Recent studies of behavioural physiology on animals have suggested the crucial role of peripherally physiological signals in eliciting arousal and emotion. Heart rate (HR) is one of the useful and critical signals to measure autonomic regulation as a physiological basis for arousal and emotion in response to biologically significant stimuli such as social encounter with conspecific individuals. However, our understanding of peripherally physiological response such as HRs and autonomic activities under social contexts of non-human animals is still limited, particularly in birds. Here, we examined the autonomic activity of behaving crows exposed to a dominant and a subordinate conspecific by using non-invasive electrocardiogram recording. We found different patterns of autonomic responses dependent on the relative dominance position: dominant crows encountering subordinates showed the elevation of sympathetic activity, whereas subordinates encountering dominants showed decreased HR with elevated parasympathetic activity. This is the first study in birds to report different autonomic responses dependent on relative dominance positions during dyadic social encounters. The present study advances our understanding of the role of the peripheral autonomic system, as an interactive system with the brain, in eliciting emotion/arousal associated with socially challenging environments from an evolutionary perspective.

  • Measurement of urinary mesotocin in large-billed crows by enzyme-linked immunosorbent assay.

    Seguchi A. Mogi K. Izawa E-I

    Journal of Veterinary Medical Science 84   520 - 524 2022.05

    Joint Work, Corresponding author, Accepted

  • Socio-ecological correlates of neophobia in corvids.

    Miller R, Lambert ML, Frohnwieser A, Brecht KF, Bugnyar T, Crampton I, Garcia-Pelegrin E, Gould K, Greggor AL, Izawa E-I, Kelly DM, Li Z. Luo Y, Luong LB, Massen JJM, Nieder A, Reber SA, Schiestl M, Seguchi A, Sepehri P, Stevens JR, Taylor AH, Wang L, Wolff LM, Zhang Y, and Clayton NS

    Current Biology (Current Biology)  32 ( 1 ) 74 - 85 2022.01

    Research paper (scientific journal), Joint Work, Accepted,  ISSN  09609822

     View Summary

    Behavioral responses to novelty, including fear and subsequent avoidance of novel stimuli, i.e., neophobia, determine how animals interact with their environment. Neophobia aids in navigating risk and impacts on adaptability and survival. There is variation within and between individuals and species; however, lack of large-scale, comparative studies critically limits investigation of the socio-ecological drivers of neophobia. In this study, we tested responses to novel objects and food (alongside familiar food) versus a baseline (familiar food alone) in 10 corvid species (241 subjects) across 10 labs worldwide. There were species differences in the latency to touch familiar food in the novel object and novel food conditions relative to the baseline. Four of seven socio-ecological factors influenced object neophobia: (1) use of urban habitat (versus not), (2) territorial pair versus family group sociality, (3) large versus small maximum flock size, and (4) moderate versus specialized caching (whereas range, hunting live animals, and genus did not), while only maximum flock size influenced food neophobia. We found that, overall, individuals were temporally and contextually repeatable (i.e., consistent) in their novelty responses in all conditions, indicating neophobia is a stable behavioral trait. With this study, we have established a network of corvid researchers, demonstrating potential for further collaboration to explore the evolution of cognition in corvids and other bird species. These novel findings enable us, for the first time in corvids, to identify the socio-ecological correlates of neophobia and grant insight into specific elements that drive higher neophobic responses in this avian family group. Video abstract: [Figure presented]

  • Scalable representation of time in the hippocampus

    SHIMBO Akihiro, Izawa E-I., Fujisawa Shigeyoshi

    Science Advances 7 ( 6 ) eabd7013 2021.02

    Research paper (scientific journal), Joint Work, Accepted

     View Summary

    Hippocampal “time cells” encode specific moments of temporally organized experiences that may support hippocampal functions for episodic memory. However, little is known about the reorganization of the temporal representation of time cells during changes in temporal structures of episodes. We investigated CA1 neuronal activity during temporal bisection tasks, in which the sets of time intervals to be discriminated were designed to be extended or contracted across the blocks of trials. Assemblies of neurons encoded elapsed time during the interval, and the representation was scaled when the set of interval times was varied. Theta phase precession and theta sequences of time cells were also scalable, and the fine temporal relationships were preserved between pairs in theta cycles. Moreover, theta sequences reflected the rats' decisions on the basis of their time estimation. These findings demonstrate that scalable features of time cells may support the capability of flexible temporal representation for memory formation.

  • Sex-specific effects of cooperative breeding and colonial nesting on prosociality in corvids.

    Horn L., Bugnyar T., Griesser M., Hengl M., Izawa E-I., Oortwijn T., Rössler C., Scheer C., Schiestl M, Suyama M., Taylor AH., Vanhooland L-C., von Bayern AM, Zürcher Y, Massen JJ.

    eLife (eLife)  9   e58139 - 244 2020.10

    Research paper (scientific journal), Joint Work

     View Summary

    © 2020, eLife Sciences Publications Ltd. All rights reserved. The investigation of prosocial behavior is of particular interest from an evolutionary perspective. Comparisons of prosociality across non-human animal species have, however, so far largely focused on primates, and their interpretation is hampered by the diversity of paradigms and procedures used. Here, we present the first systematic comparison of prosocial behavior across multiple species in a taxonomic group outside the primate order, namely the bird family Corvidae. We measured prosociality in eight corvid species, which vary in the expression of cooperative breeding and colonial nesting. We show that cooperative breeding is positively associated with prosocial behavior across species. Also, colonial nesting is associated with a stronger propensity for prosocial behavior, but only in males. The combined results of our study strongly suggest that both cooperative breeding and colonial nesting, which may both rely on heightened social tolerance at the nest, are likely evolutionary pathways to prosocial behavior in corvids.

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Papers, etc., Registered in KOARA 【 Display / hide

Reviews, Commentaries, etc. 【 Display / hide

  • Understand the evolution of animal behaviour at the different levels: brain/body anatomy and physiology, and behavioural functions

    Ei-Ichi IZAWA

    Science IMPACT (Science Impact Ltd.)  12   70 - 72 2018

    Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Single Work

  • カラスから探る社会認知機能の進化 -知性に大脳“皮質”は必要か?-


    科学 (岩波書店)  79   678 - 681 2009

    Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Single Work

  • カラスの脳と行動から探る知性の進化


    脳21 (金芳堂)  10   355 - 359 2007

    Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Single Work

Research Projects of Competitive Funds, etc. 【 Display / hide

  • 個体間の宥和関係形成を支える脳-内臓回路の比較認知神経科学研究


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Principal investigator

  • 身体拡張性の比較心理学


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Challenging Research (Exploratory) , Principal investigator

  • 情動をうみだす脳と身体の協働システムの比較認知神経科学研究


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Principal investigator

  • Investigating visuomotor control mechanisms in birds.


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, Principal investigator


Courses Taught 【 Display / hide











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Memberships in Academic Societies 【 Display / hide

  • 日本動物心理学会

  • 日本動物行動学会

  • 日本鳥学会

  • 日本動物学会

  • 日本比較生理生化学会


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Committee Experiences 【 Display / hide

  • 2014.07

    理事, 日本動物心理学会

  • 2016.04

    科学技術予測センター専門調査員, 文部科学省

  • 2018.01

    評議員, 比較生理生化学会

  • 2020.10

    連携会員(第25期), 日本学術会議