The Multitasker's Dilemma

For everyone who thinks they're maximizing their time by texting while driving, or posting Tweets and Facebook updates while compiling sales data in another window, or cooking while watching TV, cognitive scientists beg to differ. Multitasking isn't just ineffective, it can be dangerous. 

 

How Distraction Can Disrupt You

A new study shows the effect of losing your focus.

We live in a world of distraction.

When you sit at your computer trying to write or work, there is a real danger that you will get interrupted by an email, instant message, text message, or phone call. Even if you do your best to skip past the distractions, there still may be a moment where you have to stop and decide whether to answer the phone or check your email—and that itself is a distraction..

What influence do all those small interruptions have on your ability to perform complex tasks?

This question was addressed in a clever set of studies by Erik Altmann, Greg Trafton, and David Hambrick, described in a paper in the February 2014 issue of the Journal of Experimental Psychology: General

To explore the question, the researchers had to develop a complex task that would allow them to observe errors. Participants saw a computer screen with a box in the center. In each trial, there was a number and a letter. One of the characters was inside the box, the other outside. One character was either in italics or underlined. One was either red or yellow. The character outside the box was either above or below it. 

The task required participants to perform a sequence of different judgments in a sequence. To help participants remember the sequence, the order of the tasks could be remembered by using the word UNRAVEL. For example, the first task (U) asked whether a character was underlined or in italics. On the next trial, participants did the N task—Is the letter near or far from the front of the alphabet? Following that, they did the R task—Is the colored character red or yellow? Then A—Is the character above or below the box?; V—Is the letter a vowel or a consonant?; E—Is the digit even or odd?; and finally, L—Is the digit more or less than 5? After doing the L task, the sequence returned to U.

To respond to a particular task, participants simply typed the first letter of the response on a computer keyboard. So, in the U task, they typed either a U for underlined or an I for italics. 

There are two interesting aspects to this task: First, the sequence is complicated. Second, the individual tasks differ in how hard they are to perform: Deciding whether a character is above or below the box is easier than figuring out whether the letter is near or far from the start of the alphabet.

To look at interruptions, a second task was added periodically. A box would appear on the screen with a code on it. The code was a few letters or numbers. Participants had to type the code's letters or numbers to continue with the primary task. Some participants got four-character codes; others got two-character codes. That means that the interruptions were either about four seconds long or about two seconds long. These interruptions happened randomly, about once every six trials.

How did the interruptions affect performance of the task?

These brief interruptions influenced people’s ability to remember where they were in the sequence. People who got long interruptions (having to type four characters) were about three times more likely to make an error on the trial following the interruption than on trials with no interruption. People who got short interruptions (having to type two characters) were about twice as likely to make an error on the trial following the interruption than on trials with no interruption.

The errors caused by the disruptions were sequence errors. Basically, the interruptions caused people to lose their place. Most often, they mistakenly repeated the task they had just done, or did the one that should have followed the one they were supposed to do next. 

The results related to the difficulty of the tasks were also interesting. As I mentioned, some tasks were easier than others. This ease was reflected in the likelihood that people would make an error. For example, people made more errors on the N task (near vs. far from the start of the alphabet) than on the U task (underlined vs. italics). But the effect of the interruptions was the same for easy and hard tasks. 

Putting this all together, even very short interruptions are particularly bad when people are performing tasks that require a sequence of steps. The interruption disrupts people’s ability to remember where they are in the sequence, and so they are likely to carry out the wrong step following an interruption. 

Just one more reason to try to keep your work environment free of even tiny distractions. 

 

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The Multitasker's Dilemma