BioND — Dynamics of Biological Networks

Opinion Formation

Social opinion formation is cental to the functioning of human society, but also many animal populations. In the opinion formation process the opinions of individual agents are influenced by the individuals' social environment and personal concerns. Simultaneously the environment is shaped by the actions and interactions of the agents, which depend at least in part on the opinions held. Understanding global phenomena in a society by describing the evolution of opinions at the individual level, is a task which has gained much attention in the past decade. In particular, opinion formation has attracted network scientists who model a society as a network of interacting individuals. Network models of opinion formation models treat agents as network nodes, social interactions as network links, and opinions as an internal state of the node. If conflicting opinions exist in a network, it is interesting to wether eventually a consensus is reached and if yes, which opinion prevails. One phenomenon which can prevent consensus is the fragmentation transition, in which the network breaks into parts. We proposed an approach that allows precise analytical estimation of this transition (Böhme and Gross 2011). Furthermore we proposed network models for social opinion formation are analytically tractable and have been verified in experiments with swarming animals (Zschaler et al. 2011, Couzin etal. 2011). A future challenge will be to extend these approaches to more realistic models, e.g. incorporating a continuous opinion space.

Key Publications

Consensus time and conformity in the adaptive voter model
Tim Rogers and Thilo Gross
Physical Review E 88, 030102-5, 2013.
(abstract) (link to publisher) (arXiv) (download preprint)

Early fragmentation in the adaptive voter model on directed networks
Gerd Zschaler, Gesa A. Böhme, Michael Seißinger, Cristian Huepe, and Thilo Gross
Physical Review E 85(4), 046107, 2012.
(abstract) (link to publisher) (arXiv) (download preprint) (media coverage)

Uninformed individuals promote democratic consensus in animal groups
Iain D. Couzin, Christos C. Ioannou, Güven Demirel, Thilo Gross, Colin J. Torney, Andrew Hartnett, Larissa Conradt, Simon A Levin, and Naomi E. Leonard
Science 334(6206), 1578-1580 , 2011.
(abstract) (supporting material) (link to publisher) (media coverage)

Analytical calculation of fragmentation transitions in adaptive networks
Gesa A. Böhme and Thilo Gross
Physical Review E 83, 035101-4 , 2011.
(abstract) (link to publisher) (arXiv) (download preprint)

Adaptive-network models of swarm dynamics
Cristián Huepe, Gerd Zschaler, Anne-Ly Do, and Thilo Gross
New Journal of Physics 13, 073022, 2011.
(abstract) (link to publisher) (arXiv) (download preprint) (media coverage)

Additional Publications

Adaptive network models for collective decision making in swarming systems
Li Chen, Cristian Huepe, and Thilo Gross
Physical Review E 94, 022415, 2016.
(abstract) (link to publisher) (arXiv) (download preprint)

Fragmentation transitions in multi-state voter models
Gesa A. Böhme and Thilo Gross
Physical Review E 85, 066117-10, 2012.
(abstract) (link to publisher) (arXiv) (download preprint)

Adaptive coevolutionary networks: a review
Thilo Gross and Bernd Blasius
Journal of the Royal Society Interface 5(20), 259-271, 2007.
(abstract) (link to publisher) (arXiv) (download preprint)

Media Coverage

Chris Löwer, P.M., 2013-02-01
Nur scheinbar eine einförmige Masse: Fische im Schwarm sind nicht alle gleich – es gibt „meinungsbildende“ und Mitläufer.
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Sunita Sohoni, MaddowBlog, 2012-04-24
Turns out physics can explain more than just why a ball bounces or a tea kettle whistles. Physics can also help explain why American politics is so polarized. We discovered this when Rachel was cited in a physics paper (pdf) published this month by the American Physical Society.
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Manuela Lenzen, Frankfurter Allgemeine Zeitung, 2012-03-14
Ignoranten sind eine Gefahr für die Demokratie. Wie leicht könnten sie in ihrer Ahnungslosigkeit dem erstbesten Demagogen aufsitzen! Stimmt nicht, sagen Ian D. Couzin und Mitautoren: Uninformierte Individuen befördern den demokratischen Konsens - jedenfalls bei Notemigonus crysoleucas, einem schwarmbildenden Süßwasserfisch.
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CBC Radio, 2011-12-19
We journalists like to think that what we do is vital for democracy. That keeping the people informed of a complex world empowers each individual, and helps people make the best choices for the whole of society. According to a new study published in the journal Science, however, we've got it all backwards. The conclusion of the study is that the health of a democracy is dependent on keeping people UN-informed. Or some of them, anyway.
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Rob Waugh, Daily Mail Online, 2011-12-19
A well-informed, interested public is often hailed as the 'ideal' of democracy. But a new Princeton study suggests that the opposite could be the case - and that people who have no interest at all could be vital to the working of a democratic society.
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Scinexx, 2011-12-19
Ob in einem Fischschwarm oder in einer menschlichen Gesellschaft: Soziale Lebewesen müssen gemeinsam Entscheidungen treffen. Nicht immer setzt sich dabei die Mehrheit durch. In manchen Fällen gelingt es einer zielstrebigen kleinen Gruppe, die ganze Gemeinschaft in ihrem Sinne zu beeinflussen. Ein Forscherteam hat jetzt anhand von Computermodellen und Verhaltensstudien an Fischen herausgefunden, dass uninformierte Individuen die Entscheidung einer Mehrheit unterstützen und verhindern können, dass sich eine besonders entschlossene Minderheit durchsetzt.
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PTI, Firstpost, 2011-12-19
Ignorance is bliss, it’s often said, but it seems it can also promote democracy, a new study based on animal behaviour says.
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Jeffrey Kluger , Time, 2011-12-19
The Tea Party and the Occupy Wall Streeters owe a lot to a little fish called the golden shiner.
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Jürgen Schönstein, Science Blogs, 2011-12-19
Auf diesen knappen Nenner lassen sich die Ergenisse des Papers Uninformed Individuals Promote Democratic Consensus in Animal Groups bringen, das in der aktuellen Ausgabe von Science erschienen ist.
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Christopher Shea, Wall Street Journal, 2011-12-19
Computer models and experiments with shiners, a kind of fish, demonstrate that, within groups, members with weak preferences can prevent minorities with strongly held views from getting their way.
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Christine Lepisto, Treehugger, 2011-12-18
First of all, kudos to Iain Couzin and his team at Princeton for an elegant bit of research using shiner fish to validate computer models exploring the effect of the uninformed population on consensus when opposing minority interests threaten to doom decision making.
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Brunei Times, 2011-12-17
It might sound fishy, but researchers at Princeton University say minnows make perfect lab rats when it comes to exploring the surprising power of the uninformed in group decision-making.
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Eberhard Lauth, The European, 2011-12-17
Uninformierte und Ungebildete können sich jederzeit von Modernisierungsverlierern zum entscheidenden Faktor für Umbrüche entwickeln. Das ist gerade jetzt wichtig. Und die Fische machen es vor.
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St. Albert Gazette, 2011-12-17
A new study suggests that uninformed voters may help, not hinder, democratic decisions.
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Gill Eapen , Scientific Sense, 2011-12-16
A recent study shows that some percentage of uninformed (ignorant) individuals promote democratic consensus in animal groups. This is a very interesting finding as the same appears to be true in complex human societies as well. Through theory and experiments, the article demonstrates that the presence of uninformed individuals inhibit the process of domination by a strongly opinionated minority. If the strongly opinionated minority is pushing toward an optimal outcome for the system, ignorant participants will slow them down.
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Kate Shaw, Wired, 2011-12-16
How do groups of animals make collective decisions? Last week, we learned that bees reach consensus by headbutting those with opposing views. But in many other species, the decision-making process is a bit more democratic. In cases where social animals are unrelated and have different self-interests (such as our own), contrasting opinions are common. But it can be just as common for individuals to either be uninformed about the options, or simply not care much about the decision.
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BBC.co.uk, 2011-12-16
Disinterested individuals are vital for achieving a democratic consensus, according to a study in the journal Science.
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Emily Badger, Miller-McCune, 2011-12-15
In a lesson taught by schools of fish, researchers determine that uninformed individuals are actually a benefit to democracy by sanding off extreme views.
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Susan Milius, ScienceNews, 2011-12-15
Decisions can be more democratic when individuals with no preset preference join a group
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Paul Basken, The Cronicle of higher education, 2011-12-15
As Congress proves itself increasingly dysfunctional and captive to extremists, lots of people may be asking themselves: What kind of fish-brained voters keep electing these guys?
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AFP, ABC Science, 2011-12-15
It might sound fishy, but US researchers say minnows make perfect lab rats when it comes to exploring the surprising power of the uninformed in group decision-making.
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Science Daily, 2011-12-15
Contrary to the ideal of a completely engaged electorate, individuals who have the least interest in a specific outcome can actually be vital to achieving a democratic consensus.
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Eva Obermüller, ORF.at, 2011-12-15
Der mündige und informierte Bürger ist Grundlage jeder funktionierenden Demokratie, so die gängige Annahme. Eine Studie besagt hingegen: Unwissende, interesselose Individuen sind ebenso wichtig für den demokratischen Konsens.
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Joseph Castro, LiveScience, 2011-12-15
Ignorance can be bliss, but it seems it can also promote democracy.
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Joseph Castro, MSNBC.com, 2011-12-15
Minority can persuade majority, until the unknowing come along, study finds.
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AFP, Ottawa Citizen, 2011-12-15
It might sound fishy, but researchers at Princeton University say minnows make perfect lab rats when it comes to exploring the surprising power of the uninformed in group decision-making.
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Improbable Research, 2011-12-15
A democracy without a substantial number of uninformed individuals, may not know what it’s doing, metaphorically speaking. So implies this new study
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Costa Rica Rainforest Radio, 2011-08-02
Hoy las redes sociales están cambiando el modo y las costumbres de muchas personas alrededor del mundo. Por ejemplo hoy buscamos opiniones de dónde salir, qué hacer, cómo buscar trabajo, etc., y estas decisiones son influidas por nuestros amigos y conocidos.
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Scinexx, 2011-07-25
Interaktion zwischen Einzeltieren entscheidet über Richtung des Schwarms.
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om, Andes, 2011-07-24
Investigadores del Max Planck Institute for Physics of Complex Systems y un científico norteamericano de la National Science Foundation, desarrollaron un estudio que demuestra la importancia de las redes sociales para las langostas.
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Antenna 3, 2011-07-23
Gli amici su Facebook comunicano tra loro come fanno le locuste nello sciame: quando si tratta di prendere delle decisioni, infatti, questi insetti si fanno condizionare dal parere dei simili che le circondano nel loro ’social network’.
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ACM TechNews, 2011-07-20
The swarming behavior of locusts is created by the same social networks that humans adopt
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Kanal 8, 2011-07-20
Das Schwärmen von Heuschrecken folgt ähnlichen Gesetzmäßigkeiten wie unsere Meinungsbildung über Facebook oder Twitter.
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Focus Online, 2011-07-20
Nicht nur wir Menschen sind in Netzwerken miteinander verbunden. Auch ein Heuschreckenschwarm ist sozial organisiert. Und wie in unserer Gesellschaft gibt es auch hier Ausreißer, die aus der Reihe tanzen. Das wirkt sich auf alle aus.
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Ansa.it, 2011-07-19
Le decisioni si prendono nello stesso modo negli sciami e nei social network
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Minuto a Minuto, 2011-07-18
Para muchos las redes sociales son imprescindibles en su vida. Por dónde salir, qué hacer, cómo buscar trabajo, etcétera son algunas de las decisiones en las que nuestros amigos y conocidos influyen en nuestras decisiones. Ahora un equipo internacional de investigadores ha demostrado que los enjambres de langostas se crean con el mismo tipo de redes sociales que adoptamos los humanos.
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National Geographic, Germany, 2011-07-18
Das Schwärmen von Heuschrecken folgt ähnlichen Gesetzmäßigkeiten wie unsere Meinungsbildung über Facebook oder Twitter.
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Sveriges Radio, 2011-07-18
Vad har vi människor som använder facebook gemensamt med vandringsgräshoppor? Jo våra sociala nätverk avgör till stor del vilka beslut vi tar.
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Gunnar De Winter, Science 2.0, 2011-07-17
Twitter and Facebook have been studied extensively and have provided some insights into the formation and maintenance of human social networks. But could this approach be adapted to gain understanding of swarming behavior in animals, say, locusts?
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Azerbaijan Today, 2011-07-16
Social studies of Facebook and Twitter have been adapted to gain a greater understanding of the swarming behaviour of locusts.
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ellagis, Squidoo, 2011-07-15
How a swarm of animals - a swarm of locusts, for example - decides where to go, where to stop, what to eat all together? It was a big question, until researchers from the Max Planck Institute tried to answer using the rules of the social networks. Surprise: they fit.
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Kurzweil, 2011-07-15
Insect swarming is created by the same kind of adaptive-network mechanisms that humans adopt for social networks
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EP, elEconomista.es, 2011-07-15
Los estudios sociales realizados sobre Facebook y Twitter se han adaptado para comprender el comportamiento de los enjambres de langostas, según se desprende de un estudio publicado esta semana por 'Institute of Physics and German Physical Society's New Journal of Physics'.
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Público.es, 2011-07-15
Una investigación demuestra que los enjambres tienen una estructura parecida a Facebook y Twitter.
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Le Scienze (Italian edition of Scientific American), 2011-07-15
Studi sociali sugli utenti di Facebook e Twitter sono stati utilizzati per comprendere come i loro immensi sciami si coordinino per muoversi tutti insieme anche su grandi distanze.
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