I've found that every time I try to multitask neither task happens optimally.

The science seems to say what I perceived was right.
Interestingly when I ride and take note of vehicles as to when I first see them, and talking aloud in my helmet I call every vehicle a car in my commentary. Simply because the next step to say SUV, van, truck takes more brain processing power and time. So what, how might the inability to multitask affect making a commentary while riding? I think we can train the brain to process more information at a faster pace, but what are the limits and still be safe?