Well, I didn't do any B Spec Racing for about 5 days, when I left my drivers they were both up arrows (green I think) when I came back 5 days later they were both down arrows (orange?), I raced each of them about 4 times and they were still down arrows. The next morning they were up green arrows!!! So i guess the races boosted their morale.
I have also heard if you race them too much it will go down orange after a while. So maybe its both fatigue and morale, which would be horrible because how are we supposed to know which it is. PD really did a horrible job with this, no explination to it no advanced mode showing drivers feelings or fatigue, just stupid arrows that sort of randomly change.
two things I would love in a patch which will never happen:
1) Damage indicators showing exactly how much your engine and chassis are damaged so we know if its worth the 1/2 new price repair bill!
2) B Spec driver improvements, as far as telling us more about the drivers instead of just stupid arrows! Arrows are great for a quick glance but let us see more info if we want.