Long-Distance Connections Fast-Track Social Behaviors

Summary: A new study explores how human behaviors spread through social networks, revealing that long ties—connections that bridge distant parts of a network—significantly accelerate the adoption of new behaviors and ideas.

Contrary to previous beliefs that closely knit groups are more effective in spreading complex behaviors, this study demonstrates that long ties facilitate broader reach and quicker adoption across diverse populations. By using mathematical models on circular lattices, the team showed that even minimal probabilities of adoption can lead to widespread contagion if the network includes long ties.

This finding has implications for understanding social behaviors and could influence strategies in marketing and public health.

Key Facts:

  1. Long ties in social networks allow for rapid and wide-reaching spread of behaviors, surpassing the influence of tightly knit, localized groups.
  2. The study utilized mathematical and statistical methods to analyze contagion spread, finding that minimal adoption probabilities are enough for significant contagion with long ties.
  3. Insights from this research are also relevant to understanding neural activity in the brain, suggesting broader applications of these network dynamics.

Source: University of Pittsburgh

Human beings are likely to adopt the thoughts, beliefs, and behaviors of those around them. 

Simple decisions like what local store is best to shop at to more complex ones like vaccinating a child are influenced by these behavior patterns and social discourse. 

This shows outlines of people with lines connecting them.
Similar network dynamics arise in the study of neural activity in the brain. Credit: Neuroscience News

“We choose to be in networks, both offline and online, that are compatible with our own thinking,” explained Amin Rahimian, assistant professor of industrial engineering at the University of Pittsburgh Swanson School of Engineering.

“The social contagion of behavior through networks can help us understand how and why new norms, products, and ideas are adopted.” 

Initially, researchers thought highly clustered ties that are close together in networks created the perfect environment for the spread of complex behaviors that require significant social reinforcement.

However, Rahimian, alongside a team of researchers from Massachusetts Institute of Technology (MIT) and Harvard University, counter these ideas. Long ties, which are created through randomly rewired edges that make them ‘longer,’ accelerate the spread of social contagions.

For example, in the age of social media, long ties can facilitate broader reach across different demographics and heterogeneous populations. Rather than just communicating with one’s neighbor, one may also be connecting with someone in another state – even another country. 

By using mathematical and statistical methods, the researchers were able to analyze the rate of spread over circular lattices with long ties and show that having a small probability of adoption below the contagion threshold is enough to ensure that random rewiring accelerates the spread of these contagions. 

“Mechanisms that we identify for spread on circular lattices remain valid in higher dimensions,”  explained Rahimian.

Similar network dynamics arise in the study of neural activity in the brain.

 “We are interested in the implications of these results for a better understanding of network structures that facilitate the spread of bursting activity in various brain regions,” explained Jonathan Rubin, professor in Pitt’s Department of Mathematics.

This research suggests those wanting to achieve fast, total spread would benefit from implementing intervention points across network neighborhoods with long-tie connections to other network regions, explained Dean Eckles, associate professor of marketing at MIT.

“Further work could study such strategies for seeding complex behaviors,” Eckles continued. 

About this social neuroscience research news

Author: Paul Kovach
Source: University of Pittsburgh
Contact: Paul Kovach – University of Pittsburgh
Image: The image is credited to Neuroscience News

Original Research: Closed access.
Long ties accelerate noisy threshold-based contagions” by Amin Rahimian et al. Nature Human Behavior


Long ties accelerate noisy threshold-based contagions

In widely used models of biological contagion, interventions that randomly rewire edges (generally making them ‘longer’) accelerate spread. However, recent work has argued that highly clustered, rather than random, networks facilitate the spread of threshold-based contagions, such as those motivated by myopic best response for adoption of new innovations, norms and products in games of strategic complement.

Here we show that minor modifications to this model reverse this result, thereby harmonizing qualitative facts about how network structure affects contagion.

We analyse the rate of spread over circular lattices with rewired edges and show that having a small probability of adoption below the threshold probability is enough to ensure that random rewiring accelerates the spread of a noisy threshold-based contagion.

This conclusion is verified in simulations of empirical networks and remains valid with partial but frequent enough rewiring and when adoption decisions are reversible but infrequently so, as well as in high-dimensional lattice structures.

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