We’ve all read the articles. The science looms like a road sign warning: Danger! There’s no such thing as multitasking. Yet … I still do it, don’t you? I’ve even been known to count myself as the exception to the rule. (Just like I can drive more safely than the next person at higher than the posted speeds.)

After all, I can read and chew gum at the same time, listen to the radio and drive, talk on the phone and sort laundry. Isn’t that multitasking? Many of us successfully monitor email and search the web all while listening in on a conference call without missing a beat. Heck, I’m checking my email while I’m writing this – and my thought trains are running just fine. Tell me that’s not multitasking.

The short answer: It’s not. At least not according to the brain science.

The proof? Give me a test on how accurately I can recount the monthly forecasts that were presented in that conference call and, alas, I wouldn’t do as well as the person who wasn’t perusing the online take-out menu from the local taqueria. And, darn, that email I sent during the call had an unfortunate typo!

If I’m driving to a client meeting at a place where I’ve never been, don’t ask me later to reliably recount the headline news I heard on the radio. While I may be listening or even carrying on a conversation en route, as long as my non-conscious brain (the part that runs on automatic) is in the proverbial driver’s seat, I’ll reach my meeting just fine. But as soon as I miss a turn or need to stop suddenly for an errant pedestrian, the “boss” of my brain (my prefrontal cortex) kicks in, and other thought occupants are immediately shunted to my brain’s back seat or, worse, forgotten.

Think of multitasking as one big competition for our attention. Just like a plant needs water, important decisions, solutions and judgments require focused attention. The more important the task, the more attention required from our prefrontal cortex, which is not only tiny compared to the brain’s backseat (its automatic counterpart) but also requires many more resources and tuckers mighty easily. Fatigue, mostly in the form of wanderlust, sets in after about 20 minutes of focused attention.

Still think you can multitask? Try this exercise: Ask your brain to take in your favorite TV show. It’s no problem; language and sight processes play nicely together. Because these processing centers live separately in our brain, they willingly cooperate without a big toll. It’s the same with driving a car: Our vision and manual centers team up well. However, call on the same modalities at the same time (e.g., to read a busy slide while listening to a speaker waxing eloquent), and since both require language processing, your brain will revolt.

To retaliate, your brain will either work hard to inhibit one of the modalities (i.e., read the slide or listen to the speaker), or it will train itself to rapidly switch back and forth. This may feel like you’re simultaneously processing (what we call multitasking), but you’re invariably losing something (or some things) in the process. One study found that only 2.5 percent of people were able to drive a simulated car while listening to detailed instructions on other tasks. However, these people were already performing those tasks at high levels, so it’s unclear how much conscious, focused attention they needed in the first place.

So, if all we need to do is to train our brains to switch effectively in order to finish those emails during that conference call, then isn’t it just semantics whether we’re actually multitasking or just switching tasks? Perhaps – as long as we’re clear that we can’t apply the same brain power to two tasks simultaneously. Something has to give.

Why is it so hard to ignore the ping of an arriving email or text, anyway? Rewards! If you’ve ever received good news in one of those emails, then you’ve experienced all the stimulus you need to want another.

So, maybe multitasking is de rigueur in today’s world. After all, our decisions can’t always be perfect. What if I added up the costs – real or opportunity – of that ticket for running a red light, hiring the wrong person or missing that conversation with a loved one because I was distracted? Some things you can never get back.

Maybe the research is correct: Those of us who think we’re good at multitasking are actually the worst offenders. Or, maybe we’ve just done a better job training our brains. Just don’t ask me to take an accuracy or memory test; the last one didn’t work out so well.