RE: Exoskeletons have a problem: They can strain the brain - osu.edu
I can only imagine that it's like any other tool, and the cognitive effort goes down as people learn how to interact with it.
Also, if you're more adept at subtracting 13 from random numbers (or if you get better at that with practice), I'd think the strain from attempting two demanding tasks at once might diminish.
I have this debate with people about "supertasking". Some studies show that the human brain is only wired to "do one thing at a time". The implication is usually that multitasking is bad in a business environment.
But I find that I can multitask when I'm accomplishing tasks that take relatively less cognitive load. I try to train myself to do multiple things at once, and it's definitely more difficult when at least one of those things is new, or it's harder to accomplish. But, it gets easier with practice.
I don't know if supertaskers are real, or if multitasking is actually possible. But I like to think we can learn to mitigate the negative effects of cognitive overload with deliberate strategy and persistence, given the right approach.
When I was commuting into the city, I used to pass the time in traffic by trying to figure out whether I could get a palindrome from peoples' license plates by following the 196 algorithm in my head (reverse the digits, then add the original number to the reversed number; repeat until a palindrome was found or I lost track of the numbers). I still do it, once in a while, but with remote work, I don't drive as often.
It never felt like it was getting any easier, but maybe I just didn't practice enough. On the other hand, driving a car requires a lot less cognitive effort now than it did when I was 16 and working on my learner's permit.
I guess the capability to multitask might depend on the nature of the tasks.
It certainly does depend on the nature of the tasks. In some studies, researchers concluded that the inability to multitask depends on whether the tasks being performed require the same type of mental activity. I don't remember specifically what led to that claim. Maybe the topic is a good candidate for a post or series.