This article is part of Tools of the Trade, a weekly series in which a variety of experts share actionable tips for achieving fast and effective results on everything from forming good habits to raising money.

This week Earl Miller, a professor of neuroscience at The Picower Institute for Learning and Memory at MIT, breaks down why you shouldn’t multitask.

Here's practical advice from a neuroscientist: Don't try to multitask. It ruins productivity, causes mistakes, and impedes creative thought. Many of you are probably thinking, "but I'm good at it!" Sadly, that's an illusion. As humans, we have a very limited capacity for simultaneous thought — we can only hold a little bit of information in the mind at any single moment.

Our brains, however, delude us into thinking we can do more. To understand how this happens, it helps to think about how we physically see the world. Barring visual impairments, we perceive our surroundings via a video camera-like, wide-angle lens. Or at least that's how it seems. In reality, our eyes are constantly darting around, 3-4 times per second, taking in our surroundings in snippets. The end looks like one image, but that's just because our brains paper these individual pieces together to create a complete picture.

The same is true for multitasking. When we toggle between tasks, the process often feels seamless — but in reality, it requires a series of small shifts. Say you stop writing a pitch for a client in order to check an incoming email — when you finally return to the pitch, your brain has to expend valuable mental energy refocusing on the task, backtracking, and fixing errors. Not only does this waste time — and introduce the possibility that you will make a mistake– but multitasking decreases your ability to be creative. Innovative thinking, after all, typically comes from extended concentration, i.e. the ability to follow an idea of thought down a network of new paths. When you try to multitask, you typically don't get far enough down any road to stumble upon something original because you're constantly switching and backtracking.

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If you're thinking "this probably just applies to other people" — wrong. In fact, studies show that people who think they are good at multitasking generally have a lower capacity for simultaneous thought. It's a rationalization fest. Frequent offenders are bad at ignoring distractions, but instead of trying to improve their ability to focus, they convince themselves that multitasking increases productivity.