A new study from Northwestern University published on March 6 suggests that shifting interactions away from familiar contacts and toward new ones can help spread ideas and behaviors more widely. The research, led by István Kovács, examined how changes in relationships affect the way activities move through networks.
The topic is important because it addresses how information, infections, and behaviors travel within social groups and other systems. The findings may influence strategies for spreading innovations or preventing the containment of new ideas within isolated groups.
Kovács said, “Learning and adaptation are intrinsic to biological and social systems, but understanding the effects of learning remains mostly unexplored in even simple models. We wanted to investigate the impact of learning on network dynamics. We found that positive incentives can strengthen existing connections, which, surprisingly, prevents activity from spreading. When connections weaken, however, the system avoids old paths and can lead to more efficient spreading.”
The study used a theoretical framework incorporating Hebbian learning rules—where repeated use strengthens connections—to show that strong ties often trap activity in loops rather than letting it reach new areas. Kovács explained this with an analogy: “It’s similar to what happens in the ant mill phenomenon. Blind fire ants follow pheromones. But they can accidentally go in a loop. As they follow the loop, the pheromone scent gets stronger, so they continue to follow the same circular trail. The same type of ‘death spiral’ can happen in our model with positive feedback.”
According to Kovács’ team’s results published online in Communications Physics (a Nature Portfolio journal), weakening ties encourages exploration across networks rather than repetition along familiar paths.
Looking ahead, Kovács plans further research into whether these effects appear in real-world networks involving people or animals and how such processes interact with complex behaviors.
