Online experiments have become a valuable research tool for researchers interested in the processes underlying cooperation. Typically, online experiments are asynchronous, participants complete an experiment individually and are matched with partners after data collection has been completed. We conducted a registered report to compare asynchronous and synchronous designs, where participants interact and receive feedback in real-time. We investigated how two features of synchronous designs, pre-decision matching and immediate feedback, influence cooperation in the prisoners dilemma. We hypothesized that 1) pre-decision matching (assigning participants to specific interaction partners before they make decisions) would lead to decreased social distance and increased cooperation; 2) immediate feedback would reduce feelings of aversive uncertainty and lead to increased cooperation; and 3) individuals with prosocial Social Value Orientations would be more sensitive to the differences between synchronous and asynchronous designs. We found no support for these hypotheses. In our study (N = 1,238), pre-decision matching and immediate feedback had no significant effects on cooperative behavior or perceptions of the interaction; and their effects on cooperation were not significantly moderated by Social Value Orientation. The present results suggest that synchronous designs have little effect on cooperation in online social dilemma experiments.

A class of two-node queueing networks with general stationary ergodic governing sequence is considered. This means that, in particular, a non-Poissonian arrival process and dependent service times, as well as a non-Bernoulli feedback mechanism are admitted. A mixing condition ensures that the limiting distributions of the number of customers in the nodes observed in continuous time as well as at certain embedded epochs can be expressed by the Palm distributions of appropriately chosen marked point processes. This gives the possibility of connecting the classical concept of embedding with a general point-process approach. Furthermore, it leads to simple proofs of relationships between the limiting distributions. An example is given to illustrate how these relationships can be used to derive explicit formulas for various stationary queueing characteristics.

Queues with delayed feedback have been little studied in queueing theory. Presented here is a rather complete discussion of such problems including queue length processes, busy period processes and several customer flow processes (e.g., departure processes). The case in which the delay mechanism is an M-server queue is studied in detail but it is shown later that many of the results carry over to a more general delay mechanism.