Cognitive Daily

Attentional blink researchers Christian Olivers and Sander Nieuwenhuis noticed something curious when they conducted their experiments. When they were testing their stimuli, they felt that they could do the task better when they were distracted. Their participants also reported that they tended to perform better when they were a little unfocused on the task.

Attentional blink, as we’ve reported before, is a short period when we’re less able to notice an item flashed briefly in our visual field. The classic experiment involves a rapidly flashed sequence of random digits or letters—Olivers and Nieuwenhuis use letters flashed every 120 milliseconds. Then after a short interval, a digit is substituted for a letter. Nearly all observers notice this, even though they only see the letter for about a tenth of a second. However, if a second digit is flashed within the next half second, the rate of detection for this digit falls measurably.

So why would participants feel they were better at detecting the second digit when they weren’t as focused on the task? Was their introspection real, or did it just seem that way while they were performing the aggravating task of picking out digits from a rapid sequence of letters?

Olivers and Nieuwenhuis developed an experiment to systematically vary how focused participants were on the task. To decrease focus, they tried two methods—music and free association. Participants did the standard attentional blink task while listening to music (half of these people were told to listen for a “yell” which was inserted into the recording about 15 percent of the time, the other half simply listened to the music—it turned out the results were the same in both cases). Another group was told to think about the upcoming Christmas shopping season while they performed the task in silence. Finally, to try to increase focus, another group was offered a small reward (worth about a penny) each time they responded correctly. The computer gave these participants a running total of their accumulated wealth as the experiment progressed. Here are the results:

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The orange line represents typical data for participants doing the task under normal conditions. Curiously, if the second digit is displayed immediately following the first digit, participants are very accurate. But if even a single letter is displayed inbetween the first digit and the second digit—corresponding to a period of 200 to 500 milliseconds—accuracy in identifying the second digit is substantially lower, declining from over 90 percent to the low 60-percent range.

The yellow line shows the results of the group that was rewarded for performance: their results were not significantly different from the standard testing condition. However, the other two groups (light blue, distracted with the shopping task, dark blue, distracted with music) showed substantially less attentional blink. In fact, the group listening to music had practically no blink at all.

Olivers and Nieuwenhuis offer three possible explanations for this phenomenon: the music and thinking about the holiday could have increased participants arousal. Their mood might also have been changed by the distracting tasks. Or, perhaps most interestingly, these distractions could have actually broadened the participants’ attention state, leading to an improved ability to detect the digits in the stream of letters.

Olivers, C.N.L., & Nieuwenhuis, S. (2005). The beneficial effect of concurrent task-irrelevant mental activity on temporal attention. Psychological Science, 16(4), 265-269.

Comments

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  2. #2 Oonagh Duffy
    December 13, 2005

    What does attentional blink reveal about attention?

  3. #3 Dave Munger
    December 13, 2005

    Oonagh,

    Good question. I’ll be attempting to offer some answers to that in today’s post. As a preliminary, I will submit to you that if there are some instances where normal attention patterns are disrupted, those are certainly areas where we should be looking in order to learn more about how attention works.

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