optimal length of movie to evoke phsyiological response

[Liza Profile]

If you want to evoke different physiological responses (such as RSA, PEP and skin conductance) what length of time should a movie be in order to measure any physiological response?

[jcndegeus Profile]

That is a very general question...
A very general answer is that you are served best by conditions that last at least 1 minute for PEP (60-sec ensemble averages are an engrained habit).
For tonic SCL levels one minute seems OK too, but stimulus locked SCRs take only 5 seconds
For RSA based on the peak-valy method you need about 10 breaths (45 sec) but for HF power the DAMS software requires at lest 4 minutes.

Eco