NASA was doing simulator studies with U.S. pilots from the 3 largest U.S. airliners and the 2 large cargo operators. HUD, with or without low level visibility aid, with or without IR, for straight or curving ILS's, without without computer generated presentation of the runway. They'd also add a chevroned 'do not land short' box on some of the approaches*. On curving approaches they'd have the runway either ahead of you, even though you'd turn at low altitude (rolling out as low at 100'???), or have the runway presented where it actually would be in space (off to the side on a curving approach).
I don't recall the expected number of approaches but we did 43 (me - 42, FO - 1) over two days. We stayed late on day 1 and kept grinding away (additional approaches?) on day 2. Ten hours in the sim. Four hrs day 1, six hrs day 2. Day 1 was inbrief, setup, familiarization, and some approaches. Day 2 was only approaches.
We were guinea pigs. There was always one observer in the simulator with us. They switched off ever hour or two. They'd set up their eye scanning system to see which way we were looking. After each approach we'd be interviewed and fill out a report on our impressions, alertness level, fatigue, any observed positives or negatives, etc. One observer had a blanket on her legs....while the FO and I (!) had sweat starting to break out on our backs despite the air-conditioning. Forty two low vis hand flown approaches, as low as 600(1200??) RVR was tiring.
In a conversation during a break the observer said my performance had changed. He wouldn't say how it had changed but they were observing performance changes. I don't know if it was improvement or degrading due to fatigue.
The observer said he'd noticed the difference between professional pilots instrument scan and non professional pilots. The eye tracking technology allowed them, if they had it fine tuned, to tell exactly what you were looking at. In our test it gave general direction we were looking but not the exact instrument. He said the scan pattern (ability? speed? IDK) of professional pilots was immediately observable. He called it 'the super scan.' He didn't mention how it differed. I mentioned that if it was observable maybe it was teachable? Anyone looking to write a PhD thesis and need an area to study???
* - I had one major, negative, reaction to the chevron's. I think it was a low vis curing approach and as you were banking at 100'(?!) in IMC with low vis (less than 2000'? less than 1000'???) the chevron would appear in your left field of view and appeared to be the base of an 'X'. Seeing an 'X', or what you think is an 'X', is very unsettling at 100' in a bank turn, while IMC, trying your darndest to align with the runway.
I have a note that the program was called RAPTOR? NASA's Frankenstein 757 - sidestick, 787 avionics, HUD, with or without LLTV and IR capability on the HUD. FO had the LLTV or IR on his ND display.