Explaining the evolution of gossip

Abstract

Gossip, the exchange of personal information about absent third parties, is ubiquitous in human societies. However, the evolution of gossip remains a puzzle. The current article proposes an evolutionary cycle of gossip and uses an agent-based evolutionary game-theoretic model to assess it. We argue that the evolution of gossip is the joint consequence of its reputation dissemination and selfishness deterrence functions. Specifically, the dissemination of information about individuals' reputations leads more individuals to condition their behavior on others' reputations. This induces individuals to behave more cooperatively toward gossipers in order to improve their reputations. As a result, gossiping has an evolutionary advantage that leads to its proliferation. The evolution of gossip further facilitates these two functions of gossip and sustains the evolutionary cycle.

Keywords: agent-based model; cooperation; evolutionary game theory; gossip; indirect reciprocity.

Fig. 1.

The evolutionary cycle of gossip. From the top of the circle, when there are some gossipers existing in the population, the reputation dissemination function of gossip makes reputations more accessible and, thus, leads more individuals to condition their behavior on others’ reputations. As a result, more individuals get concerned about their own reputations, which drives them to manage their reputations by behaving more cooperatively when interacting with gossipers, manifesting the selfishness deterrence function of gossip. The deterrent power of gossip gives gossipers an evolutionary advantage over nongossipers, which leads to the evolution of more gossipers. Again, the evolution of more gossipers facilitates the reputation dissemination and selfishness deterrence functions of gossip and sustains this cycle.

Fig. 2.

Plot (A) illustrates the evolutionary phases. Our evolutionary game consists of three phases: 1) interaction, 2) gossiping, and 3) strategy updating. In the interaction phase, a set of agents are selected to play a cooperation game with a neighbor and gain corresponding payoffs. In the gossiping phase, another set of agents are selected as speakers. If the speaker is a gossiper, they will gossip about a certain number of targets to a randomly selected neighbor. During the strategy-updating phase, another set of agents are selected to update their strategies. By repeating the iterations, we observe the evolutionary trajectories of different strategies and behaviors. Plot (B) illustrates an agent’s action as a function of their own strategy and their belief about the interaction partner’s strategy.

Fig. 3.

The evolutionary trajectories of different strategies and behaviors. The lines are average trajectories from 30 simulation runs with all the six cooperation strategies under the default parameter choice. The shadows show the SEs of the average trajectories. Plot (A) illustrates the evolution of gossipers. Plot (B) illustrates the evolution of different cooperation strategies. Plot (C) illustrates the evolution of cooperation.

Fig. 4.

Results of Steps 1 and 2. Each condition is the average of 30 simulation runs. The value is calculated as the average value from the 4,000^th to the 5,000^th iterations of each simulation run. The error bars show the SEs. On the Left side of each plot are the results from Step 1; on the Right are the results from Step 2. Plot (A) shows that gossipers evolve only when both reputation dissemination and selfishness deterrence functions exist (i.e., with-gossip and with-rep-manage). Plots (B and C) show that the existence of gossipers (yellow) increases reputation accessibility and cooperation. Plot (D) shows that opportunists evolve only when both reputation dissemination and selfishness deterrence functions exist. Plots (E and F) show that the existence of gossipers increases the proportion of reputation-sensitive agents.