In this series I will introduce how we analyzed NIRS hyperscanning data. NIRS hyperscanning is a technology where you can measure two (or more) people’s brains at the same time. This is useful in studying the brain basis of social behavior.
We will cover:
Data quality check
Wavelet coherence analysis
Group level statistics
•11 pairs of participants (total 22)
•Each pair run 4 experiments: cooperation, competition, single 1, and single 2
–Cooperation (our main task): In each trial, a gray circle appears on the screen. After 0.6-1.5s, the gray circle is filled with green (‘go’ signal). The participants were instructed to press their corresponding keys after the ‘go’ signal. If the difference between of two timing of pressing is smaller than a threshold, then they both gain a point; otherwise they both lose a point. They were instructed to maximize the points.
–Competition: Similar to the cooperation experiment, except that the participant who press the key earlier will win a point (and the other will lose a point).
–Single 1: participant 1 press button while participant 2 observes.
–Single 2: participant 2 press button while participant 1 observes.
•In each experiment, participants performed the task in two blocks, separated by a 30s rest period.
I myself played this game for quite some times and it’s not a very easy game. The two players have to press the buttons at the same time to win.
You can find the source MatLab code for the experiment below. These scripts are adopted from a previous experiment when I was in Baylor College of Medicine. You will see that the scripts are in no way well commented and it’s probably difficult to read. But in any case it might be helpful. Also note that the scripts require PsychToolbox.