Replication studies in the Netherlands: Lessons learned and recommendations for funders, publishers and editors, and universities.

Drawing on our experiences conducting replications we describe the lessons we learned about replication studies and formulate recommendations for researchers, policy makers, and funders about the role of replication in science and how it should be supported and funded. We first identify a variety of benefits of doing replication studies. Next, we argue that it is often necessary to improve aspects of the original study, even if that means deviating from the original protocol. Thirdly, we argue that replication studies highlight the importance of and need for more transparency of the research process, but also make clear how difficult that is. Fourthly, we underline that it is worth trying out replication in the humanities. We finish by formulating recommendations regarding reproduction and replication research, aimed specifically at funders, editors and publishers, and universities and other research institutes.

Dopaminergic and norepinephrinergic modulation of endogenous event-related potentials: A systematic review and meta-analysis.

Event-related potentials (ERPs) represent the cortical processing of sensory, motor or cognitive functions invoked by particular events or stimuli. A current theory posits that the catecholaminergic neurotransmitters dopamine (DA) and norepinephrine (NE) modulate a number of endogenous ERPs during various cognitive processes. This manuscript aims to evaluate a leading neurotransmitter hypothesis with a systematic overview and meta-analysis of pharmacologic DA and NE manipulation of specific ERPs in healthy subjects during executive function. Specifically, the frontally-distributed P3a, N2, and Ne/ERN (or error-related negativity) are supposedly modulated primarily by DA, whereas the parietally-distributed P3b is thought to be modulated by NE. Based on preceding research, we refer to this distinction between frontally-distributed DA-sensitive and parietally-distributed NE-sensitive ERP components as the Extended Neurobiological Polich (ENP) hypothesis. Our systematic review and meta-analysis indicate that this distinction is too simplistic and many factors interact with DA and NE to influence these specific ERPs. These may include genetic factors, the specific cognitive processes engaged, or elements of study design, i.e. session or sequence effects or data-analysis strategies.

The Collective Trust Game: An Online Group Adaptation of the Trust Game Based on the HoneyComb Paradigm.

The need to understand trust in groups holistically has led to a surge in new approaches to measuring collective trust. However, this construct is often not fully captured in its emergent qualities by the available research methods. In this paper, the Collective Trust Game (CTG) is presented, a computer-based, multi-agent trust game based on the HoneyComb paradigm, which enables researchers to assess the emergence of collective trust. The CTG builds on previous research on interpersonal trust and adapts the widely known Trust Game to a group setting in the HoneyComb paradigm. Participants take on the role of either an investor or trustee; both roles can be played by groups. Initially, investors and trustees are endowed with a sum of money. Then, the investors need to decide how much, if any, of their endowment they want to send to the trustees. They communicate their tendencies as well as their final decision by moving back and forth on a playfield displaying possible investment amounts. At the end of their decision time, the amount the investors have agreed upon is multiplied and sent to the trustees. The trustees have to communicate how much of that investment, if any, they want to return to the investors. Again, they do so by moving on the playfield. This procedure is repeated for multiple rounds so that collective trust can emerge as a shared construct through repeated interactions. With this procedure, the CTG provides the opportunity to follow the emergence of collective trust in real time through the recording of movement data. The CTG is highly customizable to specific research questions and can be run as an online experiment with little, low cost equipment. This paper shows that the CTG combines the richness of group interaction data with the high internal validity and time-effectiveness of economic games.