Why Globalized Communication may increase Cultural Polarization

1. Why Globalized Communication may increase Cultural Polarization Paper presented at 2005 International Workshop  Games, Networks, and Cascades Cornell Club (NYC), October 7-9, 2005 Andreas Flache, University of Groningen, ICS Collaborators on general project: Michael W. Macy, Cornell University James A. Kitts, University of Washington

2. Cultural diversity and global communication Two positions • Increasingly global communication homogenizes cultures • E.g. Hamelink 1983 • Increasingly global communication makes cultural differences and cross-cultural conflict more pronounced • E.g. Huntington 1996 Flache. Globalized communication and cultural polarization

3. Concepts • What is culture? • Anderson: “culture provides a set of ideas, values and beliefs that function to provide a basis for interaction and understanding among a collection of people” • Axelrod: culture is “set of individual attributes that are subject to social influence” • Globalizing communication • “broader range of interaction beyond an individuals immediate locale and across cultural groups” (Greig, 2002) • Qualitative jump through the internet Flache. Globalized communication and cultural polarization

4. Computational models of culture formation • Models proposed by Carley, Axelrod, Mark, Latane… • Homophily: the greater the similarity, the more likely the interaction (relational dynamic). • Influence: the greater the interaction, the more similar become the interactants (opinion dynamic). • Axelrod: influence is restricted to local neighbors • Dynamics • Minimal initial similarity increases probability of interaction • which then increases similarity • leading to uniformity, not diversity • Why can there be stable diversity? Flache. Globalized communication and cultural polarization

5. Axelrod’s solution: interaction thresholds • Influence stops when individuals are too different • preservation of diverse, isolated “subcultures” • Local regions become homogenous over time  • Differentiation from neighboring regions  • No more mutual influence  • Stable diversity Example of equilibrium: 5 “features”, 15 traits per feature 20x20 “world”, Flache. Globalized communication and cultural polarization

6. Implications of Axelrod’s model for globalizing communication • Modeling globalization: • Inreasing geographical range of communication • Axelrod (1997) • Increasing range  less diversity • Diversity = #distinct “cultures” in equilibrium • Initial distribution more similar across neighborhoods (random) • more overlap, i.e. smaller chance of isolation of local regions • Follow-up studies • E.g. Shibani (2001), Greig (2002) • Global mass media and larger range of interaction allow local minorities to find support against local conformity pressures  • Globalized communication may also increase diversity Flache. Globalized communication and cultural polarization

7. What is missing…(1) Continuous opinion space • Axelrod etc assume nominal opinion space • Many issues are not nominal • how much money should we spend on…? • Many traditional models of opinion formation use continuous space • e.g. French, Harary, Abelson, Friedkin, Hegselmann & Krause. • These models produce unanimity, not stable diversity, under a large range of conditions. Flache. Globalized communication and cultural polarization

8. What is missing…(2) There is no negative influence • Axelrod etc assume that agents never change opinions to decrease similarity • Empirically we know: people often have a tendency to distance oneself from “negative referents”, “profiling” • Adding negative influence in a continuous opinion space may profoundly change influence dynamics  Macy et al (2002): from uniformity to polarization (not just diversity) Flache. Globalized communication and cultural polarization

9. wij • i • j A Hopfield Model of Dynamic Attraction:Modeling negative influence and continuous opinions • Nowak & Vallacher, 1997 • Node i has + or – “opinion” on K dimensions (-1 ≤sik≤1) • Nodes i and j are tied by positive or negative weights (-1≤wij≤1) • Opinion of j can attract or repel opinion of i, depending on wij Flache. Globalized communication and cultural polarization

10. Influence depends on relations • Effect of sj on si depends on the connection between i and j • Positive weights: opinions become more similar • Negative weights: opinions become less similar • Change in position of i with regard to issue s is weighted average of distances sj-si modified by “moderation” m • Moderation: degree to which actors weigh small differences in opinion relatively less (m >1 “moderate” or “tolerant”) N = size of neighborhood j  neighborhood Flache. Globalized communication and cultural polarization

11. And relations depend on influence • Weight wij increases with agreement in the K opinions of i and j • To be precise: weight is adapted gradually to match level of (dis) agreement. K = number of opinions j  neighborhood  = learning rate Flache. Globalized communication and cultural polarization

12. More details… • Correction necessary to keep opinions within bounds • Asynchronous updating • Agent is selected at random • either weights or states are updated with equal probability Flache. Globalized communication and cultural polarization

13. Access structure channels influence • Mutual influence only for local neighbors • For example: • Agents are arranged on a circle • Parameter range (r) • % of population to which agent has access • Access is symmetrical r=20% r=50% r=10% Examples for N=20 Flache. Globalized communication and cultural polarization

14. Experiment 1: Does continuous opinion space reduce diversity? • Comparison with Axelrod: no negative influence: • weights are mapped linearly to 0..1 interval  Zero influence only if maximum difference in opinions • From dichotomous towards continuous opinions • Discreetize opinion space into g equidistant positions • Gradually increase g and test effect on diversity in equilibrium. • Diversity measured as # of different opinion vectors surviving. • We also measured variance of opinions in equilibrium • Conservative scenario • resembles conditions where Axelrod found high diversity • Opinion space is one-dimensional, k=1 (few features) • Strongly local interaction (circle, r=2%) • More settings: • N=100 • linear influence function (moderation=1) • Fast learning (=1) • Initial opinion is uniformly distributed in -1..+1 • initial weight proportional to initial agreement Flache. Globalized communication and cultural polarization

15. Experiment 1: Results • Consistent with Axelrod: • more possible opinions increase diversity (#opinions in equilibrium) • But inconsistent with Axelrod: • variance of opinions in equilibrium approaches zero as g increases • No diversity at all in continuous opinion space g = number of equidistant opinions g > 1000  continuous opinion space Flache. Globalized communication and cultural polarization

16. Experiment 2.Stable diversity in a continuous opinion space: negative influence • Experiment 1 as baseline • But now continuous opinion space • k=1, N=100,… • Strongly localized interaction (r=2%) • Manipulations: • Positive influence only (Axelrod) vs. Positive + negative influence • weights 0..1 vs. weights -1..+1. • Results • With positive influence only, unanimity in equilibrium • With pos+neg, stable polarization: two maximally different subgroups • By and large, this result is robust across a large range of conditions, e.g. for larger N, K and higher levels of m Flache. Globalized communication and cultural polarization

17. Experiment 3: What is the effect of globalizing communication? • Experiment 2 as baseline • But now always positive + negative influence of interaction • Continuous opinion space, k=1, N=100,m=1,… • Manipulation • Range of interaction increases gradually from 2%..50% • 10 replications per condition • Outcome measures (after maximally 1000 iterations): • Diversity = #distinct opinions / N • Polarization = variance of pairwise agreement • Variance of states • But first an illustrative scenario: k=2, r=2% Larger range increases influence range of “extremists” no more gradual shift of opinions between neighbouring regions agents either move towards or distance themselves from extremists pressure towards polarization Flache. Globalized communication and cultural polarization

18. liking  agreement disliking  disagreement smoking yes no A stylized explanation critical distance Flache. Globalized communication and cultural polarization

19. liking  agreement disliking  disagreement smoking yes no Tendency towards polarization Macy, Kitts, Flache, Benard (2002) A stylized example: large interaction range critical distance Flache. Globalized communication and cultural polarization

20. liking  agreement disliking  disagreement smoking yes no Local convergence eliminates extremes  cohesion when subgroups merge A stylized example: small interaction range critical distance Flache. Globalized communication and cultural polarization

21. Experiment 3: Results • Consistent with Axelrod: • a larger range of interaction decreases diversity (#opinions in equilibrium) • But inconsistent with Axelrod: • Stable diversity with continuous opinions • Increasing variance of opinions with increasing range of interaction • Increasing polarization with increasing range of interaction Range = size of local neighborhood in %population Flache. Globalized communication and cultural polarization

22. Experiment 3: Robustness tests • Positive effect of range on polarization changes, • When number of issues (k) increases • Negative ties less likely from random start • Effect tends to become negative • When moderation (m) increases • Large opinion differences weigh relatively more • Positive effect becomes stronger • Inverted U-shape effect of range possible • Range has two opposing effects: • Larger range increases overlap between neighboring regions • pressure towards conformity • ..it also increases influence range of “extremists” pressure towards polarization Flache. Globalized communication and cultural polarization

23. How can range increase polarization?The diffusion of regional conflicts Illustrative scenario: isolated caves • N=100, range=5%, k=3, moderation=1 • From a random start, homogeneity develops in most local regions, but in a small proportion of local regions polarization emerges • When ties between polarized and homogenous regions are added, agents in homogenous regions either move towards or distance themselves from extremists • Extremism spreads through random ties Flache. Globalized communication and cultural polarization

24. Robustness tests of effects of range • Noise • Qualitative effects robust against small error in perception of others’ influence (+/- .5%) • Population size • Same qualitative effects found for N=100, 200,500 • Dimensions of opinion space • Polarization occurs also with higher k, but only with much higher moderation • Moderation • The less moderation, the less polarization • Random access structure • Qualitative effects remain unchanged Flache. Globalized communication and cultural polarization

25. Conclusions • Some previous models suggest cultural diversity can persist despite global interaction range, other’s don’t • All rely on nominal opinion space. • Model with continuous opinion space and negative social influences generates tendency towards polarization when interaction gets global • Depending on moderation and #issues, effect of increasing range of interaction is • increasing polarization • decreasing polarization • Inverted U-shape • Model suggests that globalized communication may promote “diffusion of regional conflicts” Flache. Globalized communication and cultural polarization

26. Future research • Theoretical: towards analytical models • E.g. stochastic stability (Young) • Empirical: • social influence in experiments / online interaction • Is there influence? Is it negative? • E.g. world value survey and data on accessibility of internet in different countries or social strata • Is there a relationship between cultural convergence / divergence and access to the internet? Flache. Globalized communication and cultural polarization