Copying others to dare

Collective rescue occurs even among a biased collective

It is a long-established finding that collectives achieve better decisions by aggregating information or judgments, known as the wisdom of crowds. Individual errors cancel each other out, so that collectives do the right thing even if many individuals err. However, the wisdom of crowds does not work directly here, because the crowd is not wise; rather, the collective is biased towards undue risk aversion. "I wondered how social learning could still be beneficial in such a situation," states Toyokawa. "Simply copying the majority would not help us at all, it would even yield more extreme risk aversion. So, if social learning helps at all, it must be by a different mechanism."

To uncover these mechanisms, Toyokawa developed a dynamical mathematical model, which predicted that social learning can indeed promote favourable risk taking. He then proceeded to review the predictions from his model in large-scale online experiments with human subjects. Each participant played a browser-based game where they could choose between a variety of options -- which might turn out good or bad, and with different probabilities. Toyokawa observed: "When the subjects played individually without any information from other participants, they predominantly preferred safe options with lower rewards. However, when social learning was possible, that is, when participants could see what others chose -- but not know how successful others' choices were -, it became more and more likely that they choose riskier options with higher expected rewards." In other words, social learners made riskier choices that were more rewarding in the long run.

Occasionally copying others increases exploration and persistence

"By observing others' choices, we could make smarter decisions, even though every single individual's own decisions might be unduly risk averse," Toyokawa summarizes. "Herewith, we identified a key mechanism underlying this counter-intuitive result: risk-aversion was mitigated not because the majority chose the risky option, nor were individuals simply attracted towards the majority. Rather, participants' choices became risker even though the majority chose the safer alternative at the outset, by striking a right balance between what they experienced themselves and what they observed from others."

Wolfgang Gaissmaier stresses that this is a striking demonstration of the power of social learning: "Under social influence, individuals became more explorative and more persistent in trying out the risky, more profitable option, even if that option might sometimes disappoint them in the short run. And once individual risk aversion was reduced, this process perpetuated itself, as there were more and more risk takers around to be copied."

"The finding that adverse risk aversion is mitigated under social influence will help us better understand the evolution of learning under social interaction," concludes Wataru Toyokawa. "The study suggests that social learning is advantageous in wider environmental conditions than previously assumed."

The study was funded by the Cluster of Excellence Centre for the Advanced Study of Collective Behaviour