Mother–infant EEG data
**Lab setting**
The parent–infant dual-EEG has been gathered using BioSemi ActiveTwo. The infant was placed in a baby car seat on top of the table which enabled the direct eye contact between parent and infant.
The parent and infant caps contained 64 electrodes and included reference electrodes on the mastoids (M1 and M2), and a DRL and CMS electrode. For more details see *Turk E, Endevelt-Shapira Y, Feldman R, van den Heuvel MI and Levy Y (2022) **Brains in Sync: Practical Guideline for Parent-Infant EEG During Natural Interaction.** Front. Psychol. 13:833112.* doi: 10.3389/fpsyg.2022.833112
**Experimental procedure**
For this exemplar dataset, we used the free play task (e.g. natural interaction) as paradigm of 3 min, while recording dual-EEG, video and audio. EEG measures during free play represents the brain state of natural interaction between parent and infant.
