Electrodermal activity

Electrodermal activity is used in neuroscience research, especially in the field of neuromarketing.
Electrodermal activity corresponds to electric and biological activity measured using biometric data (heart rate, breathing, body movements, blood pressure).
This measures enable the researcher to highlight emotional changes of the individual.
The goal is to observe the non-intentional behavior rather than the behavior the individual consciously wants to express.

This research method is presented as secondary because the reaction phenomena are very slow. There is more time for thinking process which could skew emotional engagement.