One of the first answers out of their mouth was, “I’m really good at multi-tasking.”

When you hear that, what’s your first response?

Mine used to be a very positive one. After all, we live in a high-demand, fast-paced, globally-connected world. Who wouldn’t want someone who is a great multitasker on their team?

But the science has become increasingly clear about the dangers of multitasking. Studies show that multitasking impairs our cognitive ability and reduces the speed with which we are able to accomplish tasks.

That means a remarkable decrease in the quality and quantity of output from those who are “heavy multitaskers.” Professor Cal Newport, author of Deep Work, Rules for Focused Work in a Distracted World, tells us that even a glance at another media stream creates what he calls “attention residue.” This can significantly decrease cognitive ability for 10-20 minutes.

As he put it, heavy multitaskers are regularly “working with a serious, self-imposed cognitive handicap.” When we’re multitasking we’re actually shooting ourselves in the foot.

How do you feel about it now?

A New Economy

For many of us, who are increasingly involved in a “knowledge work” economy, this could be disastrous. In this type of economy Newport states that there are two core abilities that are needed in order to thrive. 1) The ability to quickly master hard things and 2) The ability to produce at an elite level, in terms of both quality and speed.

Unfortunately, with the rise of multitasking, many of us are operating from a place of severe disadvantage and deficit that we’ve brought upon ourselves.

Here are three specific ways that multitasking is killing your productivity and your ability to thrive.

Falling Into Our Own Trap

Multitasking involves the rapid or (apparently) simultaneous intake of various forms of media. Imagine the scene below. Given our current environment it shouldn’t be all that unfamiliar.

You are sitting at your desk. On your laptop you have three different windows that are currently open. Just a few feet away, two of your team members are discussing a situation that involves one of your key clients. In your hand is your mobile device on which you are currently receiving multiple texts. At the same time, notifications are popping up to let you know that the Blackhawks just took a 3-1 lead over the Blues and that a press conference regarding the latest blizzard is starting any minute.

As scary as it is, the scene I just described above is not uncommon.

Based on the research done by Clifford Nass and two of his associates at Stanford University, here are three ways multitasking is killing your productivity.

1. The ability to filter. This is the ability to ignore irrelevant information and focus on relevant information. The ability to avoid distractions and concentrate on what is most important at that moment.

According to Nass, for those who are highly involved in multitasking, “everything distracts them.” In another interview he said, “Multitaskers are suckers for distraction and suckers for the irrelevant, and so the more irrelevant information they see, the more they’re attracted to it.”

Because they’re inundating themselves with so much input, they are actually training their minds to not be able to focus, even when they’re not multitasking.

One of Nass’ colleagues from Stanford added, “When they’re in situations where there are multiple sources of information coming from the external world or emerging out of memory, they’re not able to filter out what’s not relevant to their current goal,” said Anthony Wagner, an associate professor of psychology. “That failure to filter means they’re slowed down by that irrelevant information.”

2. The ability to manage your working memory. This refers to our ability to keep our memories neatly organized, including the information we gather. As a result, this relates to our ability to access that information when and where it’s needed, and then relate it to other pieces of information in ways that make sense.

According to another one of Nass’ colleagues, Eyal Ophir, “The high multitaskers are always drawing from all the information in front of them. They can’t keep things separate in their minds.”

Nass spoke about one outcome of this in a lecture series he gave at Stanford in 2011 where he stated that writing samples from freshman multitaskers showed a tendency toward shorter sentences and disconnected paragraphs. He said that they were seeing less complex ideas expressed by the students. This was likely due to this inability to manage all the information that was being stored.

Unfortunately, in our knowledge economy, the ability to think creatively and solve difficult problems quickly is essential. This requires a high degree of skill in managing our working memory, which involves drawing upon what we’ve learned previously.

3. The ability to switch from one task to another. For the researchers this was the one that surprised them the most. This was the one thing they assumed these heavy multitaskers were good at, because it certainly appeared as though they were.

Wrong again, the study showed. According to Ophir, “They couldn’t help thinking about the task they weren’t doing.”

So, while from the outside it looks like multitaskers are talented at switching from one thing to another, they’re actually not doing the next task as well or as quickly as they could if their brains were better trained to focus.

According to Cal Newport, the ability to focus is actually a skill that can be learned and mastered.