Timguin

Aren't agents paid on the basis of a percentage of the actors salary? Maybe that's why they sometimes demand more than what the actor would be willing to work for?

we measured their cognitive load, their distraction, their visual attention and their arousal.

Interesting, but those terms are a bit broad to know what exactly you were testing (as in: you're never measuring any of those things directly, you're measuring features which you have to argue are valid indicators of what you want to evaluate). Can you tell us what you used to evaluate cognitive load and distraction specifically? Spectral entropy? Theta bursts? SEF?

Also, from what you're describing the participants moved their heads quite freely. Can you describe how you treated the resulting movement artefacts? Especially with a 10 channel setup I imagine you had to put quite a bit of work into removing those.

No sweat. I'll shoot you a pm. Especially the last point is something I'm constantly fighting with in my research, so I'm always interested in peoples solutions.

I'm not OP but I'm a neuroscientist. Sadly, the answers to your questions are - as always - a bit more complicated than it seems.

Firstly, when it comes to conscious tasks, you're not really "multitasking" in the sense of parallel processing. Multitasking is a bit of a catch-all term for a variety for strategies, which is why I personally don't really like to use it. Mostly, you're actually switching between tasks. That's a really ineffective process, because during the switch nothing is processed while the brain refocusses and recalls a different task to what it was doing before. There's also a bottleneck due to ressource depletion. There are also other strategies, like partial attention and more passive processing. Also, nowadays people are using the term often simply to refer to the use of multiple media devices at once. That's different, because you could perform one cognitive task on multiple devices or multiple tasks on one device.

Back on track and to your questions: Multiple studies have found a correlation between depression/anxiety and increased use of multiple devices at once. It's not known how the causal relationship looks like, but I'm guessing it's somewhat circular.

As for cognitive multitasking, it's quite well known that depression can be comorbid with frontal lobe dysfunctions and executive function problems. So the answer would be yes, a depressed individual has a higher chance of performing worse when it comes to task-switiching and memory recall than a healthy person. There are some outliers where you find people suffering from chronic depression that are actually really good at cognitive tasks. So they might simply be incredibly good naturally and the effects of depression are too weak (or non-existent) compared to their ability. I could also imagine that the high cognitive load might contribute to depression, but I'd have to read into that idea specifically.

Pretty much the same goes for lack of sleep. It affects cognitive functioning (generally much more so than depression) and therefore makes it harder and slower to perform multiple tasks at once.