The evolution of cooperation is one of the fundamental problems of both social sciences and biology. It is difficult to explain how a large extent of cooperation could evolve if individual free riding always provides higher benefits and chances of survival. In absence of direct reciprocation, it has been suggested that indirect reciprocity could potentially solve the problem of large scale coop...

Rewards are identified as an instrument that promotes cooperation in social dilemmas. All previous experimental studies on this topic use a design that allows for reciprocity with respect to play in the social dilemma, but not for reciprocity to rewards received (for example because interaction is one-shot, or because subject identity labels are randomly reassigned between periods). We introduc...

Mutualisms are thought to be destabilized by exploitative mutants that receive benefits from partners without reciprocation. Nonetheless, there is surprisingly little evidence for the spread of exploitation in mutualist populations. In particular mutualisms, non-beneficial partners are commonplace and this raises the question of whether exploitation is invading as an adaptive strategy. Here, we...

Young children are remarkably prosocial, yet the mechanisms driving their prosociality are poorly understood. In two studies, we looked at whether a need for reciprocity drives children’s prosocial behavior. In Experiment 1, children were given a puzzle task to complete in which they were either missing 2 pieces (experimental group) or not (control group). All children then received 2 puzzle pi...

Taking a structuration perspective while integrating reciprocity research in economics, this study examines the dynamics of reciprocal interactions in social Q&A communities. We postulate that individual users of social Q&A constantly adjust their kindness into the direction of the observed benefit and effort of others. Collective reciprocity emerges from this pattern of conditional strategy of...

This article reports on observations arising from the use of a simulator in the context of energy sharing (trophallaxis) that might be applied to swarms or communities of energy critical robots. Using food-sharing behavior reported for the common vampire bat species Desmodus rotundus, it is presumed that such robots would gather naturally occurring but limited fuel materials and convert them to...

Although the BitTorrent protocol incentivizes sharing by increasing a peer’s download rate, tools have demonstrated that the tit-for-tat mechanism alone is insufficient to prevent peers from downloading content without reciprocation. We propose an enhancement to the BitTorrent protocol, called Leechlock, which uses globally shared tables to track peers’ ratings over time within the swarm. The s...

In this research, on the basis of the control of electrostatic charge, a laboratory-scale triboelectrostatic separation for separating polypropylene (PP) and acrylonitrile-butadiene-styrene (ABS) in seaweed-drying net frame plastic wastes has been carried out. High density polyethylene (HDPE) in a charger material selection tests using a vertical-reciprocation system was found to be the most ef...

accessory fibers may be quite variable. The unusual responses to electrical stimulation in these patients included: 1) failure to depolarize the His bundle from the site of ventricular pre-excitation; 2) supraventricular tachycardia with two types of re-entry; 3) anterograde block in the accessory pathway with intact retrograde conduction; and 4) retrograde delay or block in the accessory pathw...

Recent efforts to understand the mechanisms underlying human cooperation have focused on the notion of trust, with research illustrating that both initial impressions and previous interactions impact the amount of trust people place in a partner. Less is known, however, about how these two types of information interact in iterated exchanges. The present study examined how implicit initial trust...