Human Factors
Trim Stab, back in 1988 I bought a book "Human Factors in Flight" by Capt. Frank H. Hawkins. He was the HF consultant for KLM where he flew for over 30 years. The book is priceless and I do recommend that you get a copy and enjoy it's contents. He does have some info on stress which you may find useful.
Good luck with it.