Natalie S. Glance

The outbreak of cooperation

We study the ongoing collective action problem among intentional agents whose choices depend not only on the past but also on their expectations as to how their actions will affect those of others. In this model agents act on the basis of imperfect information. We show that under these conditions the onset of overall cooperation can take place in a sudden and unexpected way. Likewise, defection can appear out of nowhere in very large, previously cooperating groups. These outbreaks mark the end of long transient states in which defection or cooperation persists in groups that cannot sustain it indefinitely.

Organizational fluidity and sustainable cooperation

We show that fluid organizations display higher levels of cooperation than attainable by groups with either a fixed social structure or lacking one altogether. By moving within the organization, individuals cause restructurings that facilitate cooperation. Computer experiments simulating fluid organizations faced with a social dilemma reveal a myriad of complex cooperative behaviors that result from the interplay between individual strategies and structural changes. Significantly, fluid organizations can display long cycles of sustained cooperation interrupted by short bursts of defection.

Diversity and Collective Action

We elucidate the dynamics of ongoing collective action among intentional agents with diverse beliefs and imperfect information. Their decisions on whether or not to contribute to the collective good depend not only on the past but also on their expectations as to how their actions will affect those of others. We show that in attempts at collective action the onset of overall cooperation can take place in a sudden and unexpected way. Likewise, defection can appear out of nowhere in very large, previously cooperating groups. These outbreaks mark the end of long transient states in which defection or cooperation persists in groups that cannot sustain it indefinitely. Computer experiments demonstrate these predictions, as well as verifying that diversity of beliefs among individuals acts as an additional source of uncertainty, instigating the outbreaks.

Computational Ecosystems In A Changing Environment

We study the adaptive behavior of a computational ecosystem in the presence of time-periodic resource utilities as seen, for example in the day-night load variations of computer use and in the price fluctuations of seasonal products. We do so within the context of the Huberman-Hogg model of such systems. The dynamics is studied for the cases of competitive and cooperative payoff functions with time-modulated resource utilities, and the system’s adaptability is measured by tracking its performance in response to a time-varying environment,

The dynamics of collective action

We elucidate the dynamics of ongoing collective action among intentional agents with diverse beliefs and imperfect information. The decisions on whether or not to contribute to the collective good depend not only on the past but also on their expectations as to how their actions will affect those of others. We show that in attempts at collective action the onset of overall cooperation can take place in a sudden and unexpected way. Likewise, defection can appear out of nowhere in very large, previously cooperating groups. These outbreaks mark the end of long transient states in which defection or cooperation persists in groups that cannot sustain it indefinitely. Computer experiments demonstrate these predictions, as well as verifying that diversity of beliefs among individuals acts as an additional source of uncertainty, instigating the outbreaks.

Dynamics with expectations

Abstract We present a dynamical model of interacting agents that make decisions based on expectations about the future, along with imperfect knowledge about the present and the past. We show in particular how a diversity of expectations among the agents, coupled to reward mechanisms, can generate overall dynamics characterized by cycles of almost stable behavior interrupted by sudden crashes. This process is accompanied by an ever-changing diversity in the composition of the system.