We study cooperation when agents interact with each other only infrequently (via weak links). Such interactions usually invite defection by both sides unless agents are altruistic, or there exist information aggregation institutions that facilitate the use of group punishments. We show that agents can nevertheless sustain cooperation if requests for help can be relayed. This mechanism creates l...

There are many real life situations in which large groups of agents cooperate even though any particular pair of agents interacts only rarely with one another. For example, Granovetter (1974) analyzed how workers get matched to new jobs and showed that a majority of workers found new jobs through referrals provided by ’weak links’ with other agents (see Granovetter (1973)). Such a referral freq...

The dual mechanisms of control account suggests that cognitive control may be implemented through relatively proactive mechanisms in anticipation of stimulus onset, or through reactive mechanisms, triggered in response to changing stimulus demands. Reward incentives and task-informative cues (signaling the presence/absence of upcoming cognitive demand) have both been found to influence cognitiv...