Silverstrata, indeed cognitive ability under stress varies a great deal. You can train for it but then what you are doing is ingraining an automatic response which for the less stress capable will just result in a worst case scenario reaction. Computers dont have that problem. Also if you are flying IFR then the computer knows as much as you do about which way is up. Granted, sensor failure means its over to the blow up doll, but then the real thing can suffer from heart attacks too. Currently we have a hybrid model but as computers become more powerful they are becoming smarter too. Flight engineers know the feeling.