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 decide whether to answer the phone or check your email.
What influence do 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 in a paper in the February, 2014 issue of the Journal of Experimental Psychology: General.
To explore this question, the researchers had to develop a complex task that would allow them to observe errors. In this task, participants saw a computer screen with a box in the center. On each trial, there was a number and a letter. One of the characters was inside the box, and one was outside. One character was either in italics or had an underline. One character was either red or yellow. The character outside the box was either above it 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 then 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 typed the first letter of the response on a computer keyboard. So, in the U task, they typed 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, there was a second task that happened periodically. A box would appear on the screen with a code on it. The code was a few letters or numbers. They had to type the letters or numbers into the box to continue the task. Some participants got 4-character codes, while others got 2-character codes. That means that the interruptions were either about 4-seconds long or about 2-seconds long. These interruptions happened randomly about every 6 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 4 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 2 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 in the sequence. Most often, they mistakenly did the task they had just did or did the one following the one they were supposed to do in the sequence.
The results related to the difficulty of the tasks were also interesting. As I mentioned, some of the tasks were easier than others. This ease was reflected in the likelihood people would make an error on that task. For example, people made more errors on the near vs. far from the start of the alphabet task than on the underlined vs. italics task. But, the effect of interruptions was the same for easy and hard tasks.
Putting this all together, then, 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.