A technical note on the precise timing of behavioral events in economic experiments

Abstract

The increasing use of physiological recordings in experimental economics requires a precise timing of interesting events, such as the presentation of a set of choices, the decision-making moment and the reception of feedback through the display of a decision outcome. In this note we provide a simple, accurate and inexpensive solution based on the use of external photo-sensors that detect changes in light intensity on the participants' screens occurring in synchrony with experimental events. This system ensures an accurate communication between standard programs broadly used to run behavioral economic experiments, such as z-Tree, and eye-tracking devices or biosignal acquisition systems recording physiological variables, such as skin conductance, heart rate and electroencephalogram. An example is briefly discussed, offering specific guidelines for the application of this methodology in economic contexts with strategic interaction.

$$\mu$$Cap: connecting FaceReader™ to z-Tree

“…The principle of changing colors to create precise timestamps has since been picked up by Perakakis et al (2019), who suggest the use of external photo sensors to feed changes in luminosity directly to external devices. While their approach is equally promising in terms of effectiveness, it requires setup costs: monetary (purchasing photo sensors) and non-monetary (installing and maintaining such a system).…”

On the emergence and sustainability of corruption: An experimental analysis

“…We have used a solution which to the best of our knowledge has not been previously used in any physioeconomics study so far. As argued in Perakakis et al (2013), it is the most accurate methodology for the synchronized timing of behavioral data and physiological reactions. The main challenge is how to synchronize, free of undesirable network-related lags, the z-Tree-assisted strategy submission, information screens and feedback on one hand, with the accurate timing (with 2 millisecond precision) of events necessary for the association of SCR data to their corresponding stimuli.…”