I can only think about one thing at a time.
Any girl reading this just going to roll her eyes and think, "Of course. You're a guy!" But it's not just true for me, it's true for everyone. It's true for you.
And not in that way.
At first, this claim can sound fantastic. We can talk on a cell phone while driving to work, and we can compose complex sentences while typing. But, if you stop to reflect on it, you can only do those things at the same time because at least one of them is automatic. In the first case driving is automatic, and in the second case typing is automatic. You've done them so often that you've habituated to them: doing them doesn't require any thinking. Can you still talk on your cell phone while driving through a rainstorm on unfamiliar roads? Would you still be able to concentrate on writing if you had just switched to a Dvorak keyboard? I didn't think so.
In both cases the extreme situation frustrates your habits and forces you to actively think about what you are doing at the expense of your other task. When you are thinking about driving safely in adverse conditions, you can't also hold a conversation. And while you're searching for the "e" key, you can't also compose the next line of your sonnet.
Still not convinced? Then try this experiment: Think about the taste of chocolate (that glorious silky rush of sweet earthy flavor) at the exact same time as you add 47 and 56. Really try. At the same time. If it makes your brain fuzzy in the way your mouth feels after you've had an unripe banana, you're in good company: it's impossible. You can switch back and forth really quickly, but you can't actually think about both things at the same time.
Want another experiment? Try saying "I cannot do two things at once very well" out loud while reading the next paragraph. If you are like most people (i.e., not a practiced speed reader), you'll end up reading the paragraph very slowly, one word at a time in between your spoken words.
Software often requires us to actively think about two things at once: like needing to know if the current content of the clipboard is important (when you should be thinking about the edit you want to make), or whether the "predictive" text entry on cell phones has incorrectly guessed the word you want (when you really just want to be writing your message). Unfortunately, this is like asking us to simultaneously press two buttons that are 10 feet apart. It's impossible, and it's not humane, so we'll make mistakes. But, it's not our fault.
Not being able to think about two things at once means that we can't truly "multitask" things that we need to think about. Instead, we cycle through tasks in quick succession. But be warned, there are costs. At each switch we risk losing our train of thought and even if we remain on track, it takes time to re-situate ourselves with where we were before the switch. The net effect is that it takes more time to multitask a set of actions than it does to do them sequentially.
Time for another experiment. Time yourself doing the following two actions:
1) Spell aloud, letter by letter, "Jewelry is shiny" at the same time as you write your full name.
2) Spell aloud, letter by letter, "Jewelry is shiny" and then, after you are done with that, write your name.
It took me 18 seconds to do the tasks concurrently, and eight seconds to the tasks sequentially. However, if you practice spelling "Jewelry is shiny" aloud for a couple minutes, it'll become automatic. You'll no longer have to think to do it, and you'll be able to complete the two tasks at the same time without incurring the switching cost.
What's the lesson to be learned? If you want a boost in productivity, try rethinking how you multitask so that you only ever need to think about one thing at a time.
Even if it is about that.
[Top image by Laszlo Ilyes]