Narrator: Pilots use simulators for training, like this one AT RAF Coltishall. Today, we're using it to find out what will happen if we interfere with their vital unconscious thought processes. The minds we'll be exploring belong to newly qualified pilot, Flight Lieutenant Whitney, alias Boise, and his squadron leader, Jev Milne, a highly experienced fighter pilot who fought in the Gulf War.

Boise: [inaudible].

Narrator: First, Boise is sent on a low-flying sortie. His task, to fly to the air weapons range at Hall Beach to drop a bomb on one of the targets. Boise handles the routine run without a hiccup. Mission completed. But how will he performance if we give him something else to think about, an unrelated task designed to increase his mental load.

Boise: 29, 28, 27.

Narrator: So on the same mission, he has to count backwards from 100 to zero every second to the beat of a metronome.

Boise: 62, 61, 60, 59, 57. The counting backwards wasn't as difficult as I thought it was going to be. There were a couple of becomes, one of which was around the call sign that I normally use which is in the 60s. Normally, whenever I give a radio transmission, that will be the last number say. And then, my mouth automatically stops.

Narrator: Piloting the plane was hardly affected by the counting task. That's because counting is a conscious activity. It doesn't interfere with the automatic unconscious process of flying.

Jev: There's lots of other things to do. So if you don't have the spare capacity to do a simple task such as counting backwards, then I would suggest you're in the wrong job.

Narrator: But how will Boise perform if we simply ask him to describe what he's doing as he flies the plane. In other words, describe his automatic unconscious thought processes.

Boise: [inaudible]. It feels fine at 2150, so I'm three seconds early now. Looking at the height about 250 feet. It was actually a lot harder to talk and fly the aircraft at the same time trying to explain what you're doing because most things happen just automatically. Because we've done these sort of things many times before. As soon as I have to start explaining how a certain system is working that I take for granted normally, it takes capacity away from my flying ability. Can't see the target. Oh, it's at the right.

Jev: You verbalize the task well but at the expense of flying the aircraft which is absolutely alien to everything we teach. And today, we saw the flying suffered.

Boise: So we know we got to get back onto the target.

Narrator: Having to describe something he usually does automatically is slowing Boise down. It's interfering with unconscious processing. What about Jev? He's a more experienced pilot but will he be able to cope any better when describes what he's doing.

Jev: [inaudible]. Describing everything I did did distract me disproportionately. You got a little slow again there. Come on. 450 I should have. There were phases when I could do it fairly well and phases where I probably went a little quiet.

Narrator: Jev found the task even harder than Boise because after 11 years in the cockpit, his flying skills are so embedded in his unconscious mind that explaining what he's doing really slows him down. But this is what makes him great flyer. To pilots like Jev, flying a fighter aircraft is as every day as driving a car.