Updated on 2026/03/07
理学博士 ( 京都大学 )
Natural sciences / Applied mathematics and statistics
Kyoto University Graduate School, Division of Natural Science
- 2001
Kyoto University
- 2001
Country/Region： Japan
Kyoto University Faculty of Science
- 1996
Kyoto University Faculty of Science
- 1996
Country/Region： Japan
Meiji University School of Interdisciplinary Mathematical Sciences Professor
2018.4
Meiji University School of Interdisciplinary Mathematical Sciences Associate Professor
2013.4 - 2018.3
Meiji University Graduate School of Advanced Mathematical Sciences
2011.4 - 2013.3
科学技術振興機構さきがけ「生命現象の革新モデルと展開」領域, 個人研究者
2009 - 2012
Meiji University
2007.9 - 2011.3
:JSPS Research Fellow, Tokyo Univ
2006.4 - 2007.8
:COE Research Fellow, Tokyo Univ
2003 - 2006
:Technical Officer, Tokyo Univ
2001 - 2003
THE JAPANESE SOCIETY FOR MATHEMATICAL BIOLOGY
日本応用数理学会
日本数学会
日本人類学会
日本生態学会
Evolving genealogies in cultural evolution, the descendant process, and the number of cultural traits
Joe Yuichiro Wakano, Hisashi Ohtsuki, Yutaka Kobayashi, Ellen Baake
Theoretical Population Biology 2026.4
Forward and backward modeling of cultural evolutionary processes Invited Reviewed
Joe Y. Wakano, Kenichi Aoki
Proceedings of the National Academy of Sciences 2024.11
Seiji Kadowaki, Joe Yuichiro Wakano, Toru Tamura, Ayami Watanabe, Masato Hirose, Eiki Suga, Kazuhiro Tsukada, Oday Tarawneh, Sate Massadeh
Nature Communications 15 ( 1 ) 2024.2
Evolution of dispersal under spatio-temporal heterogeneity Reviewed
Kalle Parvinen, Hisashi Ohtsuki, Joe Yuichiro Wakano
Journal of Theoretical Biology 2023.10
Hominin forager technology, food sharing, and diet breadth Reviewed
Kenichi Aoki, Joe Yuichiro Wakano
Theoretical Population Biology 144 37 - 48 2022.4
Application of the ecocultural range expansion model to modern human dispersals in Asia Reviewed
Joe Yuichiro Wakano, Seiji Kadowaki
Quaternary International 596 171 - 184 2021.9
Time to extinction of a cultural trait in an overlapping generation model Reviewed
Yutaka Kobayashi, Shun Kurokawa, Takuya Ishii, Joe Yuichiro Wakano
Theoretical Population Biology 137 32 - 45 2021.1
The components of directional and disruptive selection in heterogeneous group-structured populations Reviewed
Hisashi Ohtsuki, Claus Rueffler, Joe Yuichiro Wakano, Kalle Parvinen, Laurent Lehmann
JOURNAL OF THEORETICAL BIOLOGY 507 2020.12
The popularity spectrum applied to a cross-cultural question Reviewed
Mitsuhiro Nakamura, Joe Yuichiro Wakano, Kenichi Aoki, Yutaka Kobayashi
THEORETICAL POPULATION BIOLOGY 133 104 - 116 2020.6
Coevolutionary dynamics of genetic traits and their long-term extended effects under non-random interactions International journal
Charles Mullon, Joe Yuichiro Wakano, Hisashi Ohtsuki
Journal of theoretical biology 525 110750 - 110750 2020.3
Evolution of dispersal in a spatially heterogeneous population with finite patch sizes Reviewed
Kalle Parvinen, Hisashi Ohtsuki, Joe Yuichiro Wakano
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 117 ( 13 ) 7290 - 7295 2020.3
Lithic technology, chronology, and marine shells from Wadi Aghar, southern Jordan, and Initial Upper Paleolithic behaviors in the southern inland Levant Reviewed
Seiji Kadowaki, Toru Tamura, Katsuhiro Sano, Taiji Kurozumi, Lisa A. Maher, Joe Yuichiro Wakano, Takayuki Omori, Risako Kida, Masato Hirose, Sate Massadeh, Donald O. Henry
JOURNAL OF HUMAN EVOLUTION 135 2019.10
Evolution of cumulative culture for niche construction Reviewed
Yutaka Kobayashi, Joe Yuichiro Wakano, Hisashi Ohtsuki
JOURNAL OF THEORETICAL BIOLOGY 472 67 - 76 2019.7
Shun Kurokawa, Joe Yuichiro Wakano, Yasuo Ihara
Games 9 ( 4 ) 2018.12
Spatial heterogeneity and evolution of fecundity-affecting traits Reviewed
Kalle Parvinen, Hisashi Ohtsuki, Joe Yuichiro Wakano
JOURNAL OF THEORETICAL BIOLOGY 454 190 - 204 2018.10
Yutaka Kobayashi, Joe Yuichiro Wakano, Hisashi Ohtsuki
THEORETICAL POPULATION BIOLOGY 123 18 - 27 2018.9
Joe Yuichiro Wakano, William Gilpin, Seiji Kadowaki, Marcus W. Feldman, Kenichi Aoki
THEORETICAL POPULATION BIOLOGY 119 3 - 14 2018.2
Derivation of replicator-mutator equations from a model in population genetics Reviewed
Joe Yuichiro Wakano, Tadahisa Funaki, Satoshi Yokoyama
JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS 34 ( 2 ) 473 - 488 2017.8
Inclusive fitness analysis of cumulative cultural evolution in an island-structured population Reviewed
Hisashi Ohtsuki, Joe Yuichiro Wakano, Yutaka Kobayashi
THEORETICAL POPULATION BIOLOGY 115 13 - 23 2017.6
Laurel Fogarty, Joe Yuichiro Wakano, Marcus W. Feldman, Kenichi Aoki
HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 28 ( 1 ) 39 - 52 2017.3
The effect of fecundity derivatives on the condition of evolutionary branching in spatial models Reviewed
Kalle Parvinen, Hisashi Ohtsuki, Joe Yuichiro Wakano
JOURNAL OF THEORETICAL BIOLOGY 416 129 - 143 2017.3
Yutaka Kobayashi, Hisashi Ohtsuki, Joe Y. Wakano
THEORETICAL POPULATION BIOLOGY 111 87 - 95 2016.10
Gene-Culture Models for the Evolution of Altruistic Teaching Reviewed
K. Aoki, J. Y. Wakano, M. W. Feldman
On Human Nature: Biology, Psychology, Ethics, Politics, and Religion 279 - 296 2016.9
A paradox of cumulative culture Reviewed
Yutaka Kobayashi, Joe Yuichiro Wakano, Hisashi Ohtsuki
JOURNAL OF THEORETICAL BIOLOGY 379 79 - 88 2015.8
Avoiding toxic prey may promote harmful algal blooms Reviewed
Tommaso Scotti, Masayasu Mimura, Joe Yuichiro Wakano
ECOLOGICAL COMPLEXITY 21 157 - 165 2015.3
Factors limiting the number of independent cultural traits that can bemaintained in a population Reviewed
Laurel Fogarty, Joe Yuichiro Wakano, Marcusw. Feldman, Kenichi Aoki
Learning Strategies and Cultural Evolution During the Palaeolithic 9 - 21 2015.1
Evolutionary branching in deme-structured populations Reviewed
Joe Yuichiro Wakano, Laurent Lehmann
JOURNAL OF THEORETICAL BIOLOGY 351 83 - 95 2014.6
Direct competition results from strong competition for limited resource Reviewed
Sepideh Mirrahimi, Benoit Perthame, Joe Yuichiro Wakano
JOURNAL OF MATHEMATICAL BIOLOGY 68 ( 4 ) 931 - 949 2014.3
Trade-off between learning and exploitation: The Pareto-optimal versus evolutionarily stable learning schedule in cumulative cultural evolution Reviewed
Joe Yuichiro Wakano, Chiaki Miura
THEORETICAL POPULATION BIOLOGY 91 37 - 43 2014.2
ON OPTIMAL LEARNING SCHEDULES AND THE MARGINAL VALUE OF CUMULATIVE CULTURAL EVOLUTION Reviewed
Laurent Lehmann, Joe Yuichiro Wakano, Kenichi Aoki
EVOLUTION 67 ( 5 ) 1435 - 1445 2013.5
A mathematical description of the inclusive fitness theory Reviewed
Joe Yuichiro Wakano, Hisashi Ohtsuki, Yutaka Kobayashi
THEORETICAL POPULATION BIOLOGY 84 ( 1 ) 46 - 55 2013.3
The handaxe and the microscope: individual and social learning in a multidimensional model of adaptation Reviewed
Laurent Lehmann, Joe Yuichiro Wakano
EVOLUTION AND HUMAN BEHAVIOR 34 ( 2 ) 109 - 117 2013.3
Evolutionary Branching in a Finite Population: Deterministic Branching vs. Stochastic Branching Reviewed
Joe Yuichiro Wakano, Yoh Iwasa
GENETICS 193 ( 1 ) 229 - 241 2013.1
Adaptive Social Learning Strategies in Temporally and Spatially Varying Environments How Temporal vs. Spatial Variation, Number of Cultural Traits, and Costs of Learning Influence the Evolution of Conformist-Biased Transmission, Payoff-Biased Transmission, and Individual Learning Reviewed
Wataru Nakahashi, Joe Yuichiro Wakano, Joseph Henrich
HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 23 ( 4 ) 386 - 418 2012.12
Corrigendum to "Evolutionary and convergence stability for continuous phenotypes in finite populations derived from two-allele models" [J. Theor. Biol. 310 (2012) 206-215] Reviewed
Joe Yuichiro Wakano, Laurent Lehmann
Journal of Theoretical Biology 312 157 2012.11
Evolutionary and convergence stability for continuous phenotypes in finite populations derived from two-allele models (vol 310, pg 206, 2012) Reviewed
Joe Yuichiro Wakano, Laurent Lehmann
JOURNAL OF THEORETICAL BIOLOGY 312 157 - 157 2012.11
Evolutionary and convergence stability for continuous phenotypes in finite populations derived from two-allele models Reviewed
Joe Yuichiro Wakano, Laurent Lehmann
JOURNAL OF THEORETICAL BIOLOGY 310 206 - 215 2012.10
Evolution of species trait through resource competition Reviewed
Sepideh Mirrahimi, Benoit Perthame, Joe Yuichiro Wakano
JOURNAL OF MATHEMATICAL BIOLOGY 64 ( 7 ) 1189 - 1223 2012.6
Evolutionarily stable learning schedules and cumulative culture in discrete generation models Reviewed
Kenichi Aoki, Joe Yuichiro Wakano, Laurent Lehmann
THEORETICAL POPULATION BIOLOGY 81 ( 4 ) 300 - 309 2012.6
EVOLUTION OF SOCIAL VERSUS INDIVIDUAL LEARNING IN AN INFINITE ISLAND MODEL Reviewed
Yutaka Kobayashi, Joe Y. Wakano
EVOLUTION 66 ( 5 ) 1624 - 1635 2012.5
SPATIOTEMPORAL DYNAMICS OF COOPERATION AND SPITE BEHAVIOR BY CONFORMIST TRANSMISSION Reviewed
Joe Yuichiro Wakano
COMMUNICATIONS ON PURE AND APPLIED ANALYSIS 11 ( 1 ) 375 - 386 2012.1
Effective dispersal rate is a function of habitat size and corridor shape: mechanistic formulation of a two-patch compartment model for spatially continuous systems Reviewed
Joe Yuichiro Wakano, Kota Ikeda, Takeshi Miki, Masayasu Mimura
OIKOS 120 ( 11 ) 1712 - 1720 2011.11
Coexistence of individual and social learners during range expansion Reviewed
Joe Y. Wakano, Kohkichi Kawasaki, Nanako Shigesada, Kenichi Aoki
THEORETICAL POPULATION BIOLOGY 80 ( 2 ) 132 - 140 2011.9
Pattern formation and chaos in spatial ecological public goods games Reviewed
Joe Yuichiro Wakano, Christoph Hauert
JOURNAL OF THEORETICAL BIOLOGY 268 ( 1 ) 30 - 38 2011.1
Generous cooperators can outperform non-generous cooperators when replacing a population of defectors Reviewed
Shun Kurokawa, Joe Yuichiro Wakano, Yasuo Ihara
THEORETICAL POPULATION BIOLOGY 77 ( 4 ) 257 - 262 2010.6
The evolution of phenotypic traits in a predator-prey system subject to Allee effect Reviewed
Jian Zu, Masayasu Mimura, Joe Yuichiro Wakano
JOURNAL OF THEORETICAL BIOLOGY 262 ( 3 ) 528 - 543 2010.2
Spatial dynamics of ecological public goods Reviewed
Joe Yuichiro Wakano, Martin A. Nowak, Christoph Hauert
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 106 ( 19 ) 7910 - 7914 2009.5
Evolution of polyphenism: the role of density and relative body size in morph determination Reviewed
Joe Y. Wakano, Howard H. Whiteman
EVOLUTIONARY ECOLOGY RESEARCH 10 ( 8 ) 1157 - 1172 2008.12
Ecological public goods games: Cooperation and bifurcation Reviewed
Christoph Hauert, Joe Yuichiro Wakano, Michael Doebeli
THEORETICAL POPULATION BIOLOGY 73 ( 2 ) 257 - 263 2008.3
Do social learning and conformist bias coevolve? Henrich and Boyd revisited Reviewed
Joe Yuichiro Wakano, Kenichi Aoki
THEORETICAL POPULATION BIOLOGY 72 ( 4 ) 504 - 512 2007.12
Evolution of cooperation in spatial public goods games with common resource dynamics Reviewed
Joe Yuichiro Wakano
JOURNAL OF THEORETICAL BIOLOGY 247 ( 4 ) 616 - 622 2007.8
A theoretical study on the evolution of male parental care and female multiple mating: Effects of female mate choice and male care bias Reviewed
Motohide Seki, Joe Yuichiro Wakano, Yasuo Ihara
JOURNAL OF THEORETICAL BIOLOGY 247 ( 2 ) 281 - 296 2007.7
A mixed strategy model for the emergence and intensification of social learning in a periodically changing natural environment Reviewed
Joe Yuichiro Wakano, Kenichi Aoki
THEORETICAL POPULATION BIOLOGY 70 ( 4 ) 486 - 497 2006.12
A mathematical analysis on public goods games in the continuous space Reviewed
Joe Yuichiro Wakano
MATHEMATICAL BIOSCIENCES 201 ( 1-2 ) 72 - 89 2006.5
Evolution of extraordinary female-biased sex ratios: The optimal schedule of sex ratio in local mate competition Reviewed
J Y Wakano
JOURNAL OF THEORETICAL BIOLOGY 237 ( 2 ) 193 - 202 2005.11
Evolution of male parental care and female multiple mating: Game-theoretical and two-locus diploid models Reviewed
J Y Wakano, Y Ihara
AMERICAN NATURALIST 166 ( 2 ) E32 - E44 2005.8
The emergence of social learning in a temporally changing environment: A theoretical model Reviewed
K Aoki, J Y Wakano, MW Feldman
CURRENT ANTHROPOLOGY 46 ( 2 ) 334 - 340 2005.4
Evolution of social learning: a mathematical analysis Reviewed
J Y Wakano, K Aoki, MW Feldman
THEORETICAL POPULATION BIOLOGY 66 ( 3 ) 249 - 258 2004.11
Phase transition of traveling waves in bacterial colony pattern Reviewed
J Y Wakano, A Komoto, Y Yamaguchi
PHYSICAL REVIEW E 69 ( 5 ) 051904 2004.5
Evolution of mutualism through spatial effects Reviewed
N Yamamura, M Higashi, N Behera, J Y Wakano
JOURNAL OF THEORETICAL BIOLOGY 226 ( 4 ) 421 - 428 2004.2
Drastic growth effect may explain sympatric cannibalistic polymorphism Reviewed
J Y Wakano
JOURNAL OF THEORETICAL BIOLOGY 226 ( 1 ) 69 - 77 2004.1
Growth dynamics of Bacillus circulans colony Reviewed
A Komoto, K Hanaki, S Maenosono, J Y Wakano, Y Yamaguchi, K Yamamoto
JOURNAL OF THEORETICAL BIOLOGY 225 ( 1 ) 91 - 97 2003.11
Self-organized pattern formation of a bacteria colony modeled by a reaction diffusion system and nucleation theory Reviewed
J Y Wakano, S Maenosono, A Komoto, N Eiha, Y Yamaguchi
PHYSICAL REVIEW LETTERS 90 ( 25 ) 258102 2003.6
Self-organized pattern formation of a bacteria colony modeled by a reaction diffusion system and nucleation theory Reviewed
J Y Wakano, S Maenosono, A Komoto, N Eiha, Y Yamaguchi
PHYSICAL REVIEW LETTERS 90 ( 25 ) 2003.6
The mode transition of the bacterial colony Reviewed
N Eiha, A Komoto, S Maenosono, J Y Wakano, K Yamamoto, Y Yamaguchi
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 313 ( 3-4 ) 609 - 624 2002.10
Evolutionary dynamics of frequency-dependent growth strategy in cannibalistic amphibians Reviewed
J Y Wakano, Y Kohmatsu, N Yamamura
EVOLUTIONARY ECOLOGY RESEARCH 4 ( 5 ) 719 - 736 2002.7
A simple learning strategy that realizes robust cooperation better than Pavlov in Iterated Prisoners' Dilemma Reviewed
J Y Wakano, N Yamamura
JOURNAL OF ETHOLOGY 19 ( 1 ) 1 - 8 2001
Dynamic model of optimal age polyethism in social insects under stable and fluctuating environments Reviewed
J Y Wakano, K Nakata, N Yamamura
JOURNAL OF THEORETICAL BIOLOGY 193 ( 1 ) 153 - 165 1998.7
「人間社会と協力・学習の進化」 『「行動・進化」の数理生物学 (シリーズ 数理生物学要論 巻3）』
共立出版 2010
「バクテリアの自己組織化」 『自己組織化ハンドブック』
NTS出版 2009
1994 178 - 184 2016.4
「同調伝達による協力行動・スパイト行動の時空間ダイナミクス」
若野 友一郎
京都大学数理解析研究所講究録 ( 1663 ) 124 - 129 2009
「バクテリアコロニーパターン形成における等速進行波解の相転移」
若野 友一郎
京都大学数理解析研究所講究録 ( 1499 ) 101 - 106 2006
「反応拡散系の数値計算と可視化技術」
若野 友一郎
東京大学工学部技術報告 ( 2003 ) 113 - 116 2003
「2次元反応拡散系の数値解析技術」
若野 友一郎
東京大学工学部技術報告 ( 2002 ) 95 - 100 2002
「繰り返し囚人のジレンマゲームにおいて進化的に安定な協力を実現する学習戦略」
若野 友一郎
東京大学工学部技術報告 ( 2001 ) 137 - 140 2001
Marcus W. Feldman Prize
2020 Theoretical Population Biology Genealogies and ages of cultural traits: an application of the theory of duality to the research on cultural evolution
Yutaka Kobayashi, Joe Yuichiro Wakano, Hisashi Ohtsuki.
日本数理生物学会研究奨励賞
2006
A new stochastic model and diffusion approximation to analyze archaological and ethnographic data
Grant number：21K03357 2021.4 - 2025.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
Grant amount：\4290000 （ Direct Cost: \3300000 、 Indirect Cost：\990000 ）
Mathematical modelling and analysis of cultural and behavioral changes through dispersal and settlement of human populations
Grant number：16H06412 2016.6 - 2021.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area) Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
Grant amount：\112580000 （ Direct Cost: \86600000 、 Indirect Cost：\25980000 ）
Evolution of time allocation to learning and resource acquisition: theoretical and empirical studies
Grant number：16K07524 2016.4 - 2020.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C) Grant-in-Aid for Scientific Research (C)
Grant amount：\4940000 （ Direct Cost: \3800000 、 Indirect Cost：\1140000 ）
Mathematical analysis of Markov-process models of biological evolution
Grant number：16K05283 2016.4 - 2020.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C) Grant-in-Aid for Scientific Research (C)
Grant amount：\4550000 （ Direct Cost: \3500000 、 Indirect Cost：\1050000 ）
パレオアジア文化史学ーアジア新人文化形成プロセスの総合的研究
2016 - 2020
科学研究費補助金
Grant type：Competitive
New mathematical models for evolutionary origin of biodiversity
Grant number：25870800 2013.4 - 2017.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B) Grant-in-Aid for Young Scientists (B)
Wakano Joe Yuichiro
Grant amount：\4160000 （ Direct Cost: \3200000 、 Indirect Cost：\960000 ）
We studied moment-expansion method and meta-population fitness method as models to research the evolutionary origin of biodiversity. We found that the two methods yield exactly the same analytic result. We also found that, under natural selection produced by any two-player games, deme structure always inhibit evolutionary branching. These results suggest that, if homogenous environment is divided into deme structures, the emergence of biodiversity is not enhanced by disruptive natural selection, compared to the case of non-divided populations.
Research on Evolutionary Models of Human Learning Abililties
Grant number：22101004 2010.4 - 2015.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area) Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
AOKI Kenichi, KIMURA Ryosuke, KAWASAKI Kohkichi, WAKANO Yuichiro, KOBAYASHI Yutaka
Grant amount：\105820000 （ Direct Cost: \81400000 、 Indirect Cost：\24420000 ）
Scientific Research on Innovative Areas “RNMH” had as its goal the explication of the extinction of Neanderthals and their replacement by modern humans in terms of a difference in the cultural levels of the two species (learning hypothesis). The cultural level attained by a society depends on cultural evolutionary processes. With this in mind, our research group conducted theoretical research on the determinants of cultural evolution and on the genetic evolution of learning strategies supportive of cultural evolution. The many fruits of our research have been published in referred international journals and in books, and have contributed significantly to advancing this rapidly growing field. In addition, we conducted exploratory studies in molecular anthropology with the aim of identifying genes that may have contributed to cognitive differences between the two species.
Replacement of Neanderthals by Modern Humans: Testing Evolutionary Models of Learning
2010 - 2014
Grant-in-Aid for Scientific Research
Grant type：Competitive
ネアンデルタールとサピエンス交替劇の真相：学習能力の進化に基づく実証的研究
2010 - 2014
科学研究費補助金
Grant type：Competitive
Unified understanding of two major theories of biological evolution
2009 - 2012
JST Basic Research Programs (Precursory Research for Embryonic Science and Technology :PRESTO)
Grant type：Competitive
生物進化の２大理論の統一的理解
2009 - 2012
ＪＳＴ戦略的創造研究推進制度（個人研究型） （個人研究推進事業：さきがけ研究２１‐ＰＲＥＳＴＯ）
Grant type：Competitive
Which of the finite population effect and the spatial structure effect is dominant in ESS selection?
Grant number：20770019 2008 - 2010
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B) Grant-in-Aid for Young Scientists (B)
WAKANO Yuichiro
Grant amount：\4290000 （ Direct Cost: \3300000 、 Indirect Cost：\990000 ）
The effects of finite population and the effect of spatial structure on ESS selection are studied in various mathematical models of biology and the results were published by academic journals.
空間構造および社会構造の存在下での社会学習の進化
Grant number：06J09976 2006 - 2007
日本学術振興会 科学研究費助成事業 特別研究員奨励費 特別研究員奨励費
若野 友一郎
Grant amount：\2300000 （ Direct Cost: \2300000 ）
社会学習は、個体学習者が試行錯誤のコストを払って獲得した適応的行動を少ないコストで真似するという意味で、社会寄生行動の一種であると考えられる。社会学習の起源の問題は古くから議論されているものの、数理的な研究はまだそれほど多くはない。ヒトは社会学習を行う際に、単に集団中の個体をランダムに選んで模倣するのではなく、多数派の行動をより模倣すると言われている。このような行動は同調伝達と呼ばれ、文化の局所性の要因とした議論されてきた。しかしながら変動環境下においては、多数派の行動は必ずしも正しいとは限らないので、同調伝達をすること自体が適応的かどうかは、明らかではない。また、同調伝達の有無は社会学習の適応度を変化させるため、「同調伝達の強さ」と「社会学習への依存度」は、互いに影響を及ぼしあいながら共進化すると考えられる。Henrich&Boyd(1998)は、個体学習と社会学習を併用する個体を仮定し、2遺伝子座モデルを構築して数値計算することで、この2つは相乗的(synergistic)に働くと結論した。特に、環境変動の周期が長いほど「同調伝達の強さ」と「社会学習への依存度」はより大きい値に進化すると主張した。我々はこのモデルを多少修正した上で、Adaptive dynamicsを用いて解析し、次の結果を得た。 (1)環境変動の周期が長いほど、「社会学習への依存度」は大きくなる (2)環境変動の周期が長いほど、「同調伝達の強さ」は小さくなる
このうち、(1)は先行研究の結果と一致するが、(2)はHenrich&Boyd(1998)とは逆の結果である。この違いは、より詳細な計算の結果、先行研究の数値計算が不十分であったことが原因であることも発見した。本研究により、伺調伝達と社会学習の進化は、相乗的ではなく、むしろ排他的に起こることが明らかとなった。
(2)環境変動の周期が長いほど、「同調伝達の強さ」は小さくなる
このうち、(1)は先行研究の結果と一致するが、(2)はHenrich&Boyd(1998)とは逆の結果である。この違いは、より詳細な計算の結果、先行研究の数値計算が不十分であったことが原因であることも発見した。本研究により、伺調伝達と社会学習の進化は、相乗的ではなく、むしろ排他的に起こることが明らかとなった。
共有資源の時空間ダイナミクスを考慮した共有地の悲劇の回避メカニズム
Grant number：17770011 2005 - 2007
日本学術振興会 科学研究費助成事業 若手研究(B) 若手研究(B)
若野 友一郎
Grant amount：\2700000 （ Direct Cost: \2700000 ）
多数の個体によって共有されている資源への投資は、投資量を上回る量が回収できるとしても、投資しない個体(利己的)が投資する個体(利他的)より常に高い利得を得るために、進化しにくいと理論的に予測されている(共有地の悲劇、公共財ゲーム)。本研究の目的は、公共財ゲームを共有資源の時空間ダイナミクスを含む形に発展拡張させた数理モデルを構築し、利他行動の有利不利と、共有資源ダイナミクスの反応速度や拡散速度との関係を研究することで、どのような共有地では悲劇が回避されうるのかを、理論的に明らかにすることである。共有資源および生物個体の時空間ダイナミクスの双方に、反応拡散方程式を用いるモデルAについて、モデルの構築、解析およびコンピュータシミュレーションを行った。初期条件として、1次元空間の左半分に利己的個体、右半分に利他的個体が存在する状況を考える。空間の中央に存在する、利他的個体と利己的個体との境界がどちらに移動するかを考えることで、進化を考える。投資の効率が無限大となる極限においては、利己的個体だけの世界における利己的個体の平衡頻度は無限大となる。このような場合においては、(境界部分で戦っている利己的個体に援軍として到着する)右半分からの拡散が無限大となるため、利他的個体が利己的個体を駆逐する可能性があると考えた。しかしながら、モデルの等速進行波解がみたす力学系の、ヘテロクリニック軌道の存在について、解析的な研究を行ったところ、そのような等速進行波解が存在しないことを、厳密に証明することができた。さらにこの解析結果を支持する数値計算の結果も得た。以上の研究結果をまとめて、論文として投稿し受理された(Wakano JY, Mathematical Biosciences, in press)。
Click to view the Scopus page. The data was downloaded from Scopus API in April 24, 2026, via http://api.elsevier.com and http://www.scopus.com .