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Hey, Did You Hear? …Why We Don’t Listen

The views expressed are those of the author and are not necessarily those of Scientific American.


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Why do we sometimes not register sounds and voices around us? A wife asks her husband for the third time, “did you take the garbage out yet?” He is so glued to the big game and he still hasn’t issued a response. A kid doesn’t hear her mother tell her dinner is ready because she is fully immersed in her favorite video game. You miss part of the conversation you were having with your friends at a coffee shop because you were too busy checking for new email, comments and tweets on your smart phone for the millionth time today (that one I can relate to). What do these three scenarios have in common? Our bodies trying to balance our sensory perceptual load between vision and hearing and one of these senses ultimately falls short.

Researchers in the United Kingdom have demonstrated for the first time a phenomenon known as inattentional deafness. It seems when we are concentrated on a highly involved visual task, we block out auditory information around us that is unrelated to the task at hand. In other words, we may be involuntarily putting sounds “on mute” while we concentrate on activities that take a great deal of our attention visually and and this can turn us into poor listeners.

Inattentional Blindness:

Now we have all probably heard of something called “inattentional blindness” and the infamous visual awareness test that Chabris and Simons conducted back in 1999 in which one is asked to watch a video and count the number of times a basketball is passed by one of two teams. If you haven’t seen it, it was similar to the following video. Check it out!

Visual Awareness Test (by dothetest.co.uk):

In the original version of this test, also known as the “invisible gorilla” experiment by Chabris and Simons, the mental task of counting passes had about 50% of viewers so distracted that they were visually unaware of the gorilla walking (or in this case, the bear moonwalking) right into the middle of the screen. A moonwalking bear, hello? A gorilla beating on his chest? Come on! (For the record, I missed both!)

Perhaps you have also heard about the study that came out in 2009 in which distracted cell phone users were visually unaware of a clown on a unicycle passing them as they were walking and chatting away on their phone. I mean, really. How could you not notice a clown pedaling right passed you on a unicycle!

Visual awareness has been well researched and there are many interesting studies out there on how distractions can take away from your vision. If you’d like to have a little more fun with it, I will list a couple of other videos at the end of this post. But for now let’s turn our attention towards hearing and distractions causing a decrease in our auditory awareness. What is this newly named phenomenon of inattentional deafness?

Inattentional Deafness:

In May 2011, Macdonald and Lavie set up a series of experiments putting the theory of inattentional deafness to the test. They found subjects were able to hear a beeping sound being played through headphones while they performed a visual task on the computer if the task was relatively easy but as the level of difficulty of the visual task increased, they became unaware that a sound was even there.

The setup of the experiment went like this. On the computer screen, a series of crosses were presented to participants, one by one, each for a short interval. The cross had one green arm and one blue arm and the lengths of the arms on the cross varied slightly. Each person was asked to either indicate which arm was blue or judge which arm was longer. Determining color was thought to be a very easy visual task with a low amount of perceptual load. Conversely, participants who were asked to detect the subtle difference in length of the two arms were said to have a more challenging task, requiring more visual attention and therefore having to endure a higher perceptual load.

The experiment had three parts. In the first part, experiment 1, white noise was played through the headphones and participants were told that they were to wear the headphones throughout the experiment. Researchers said the white noise would “aid concentration by blocking out noise from people passing the testing room…[according to researchers] participants seemed to take this instruction at face value and did not seem suspicious [of the need to] block out the sound of people passing by.”

During the last cross presentation, the white noise was accompanied by a beeping sound. Participants were then stopped and asked at the end if they had heard “anything different about the sound coming through the headphones during the last trial?” Their response was noted. Then they were asked to perform one more trial in which they were told to ignore the cross and just listen to the sound coming through the headphones to make sure each person had good enough hearing to detect the sound. If they didn’t hear it when they were actively listening for it, then they were excluded from the study and replaced.

From the results in Experiment 1, Macdonald and Lavie concluded that their hypothesis was in fact correct. At times when a higher visual load was presented (determining length of the arms of the cross), the participants were less likely to hear the task-unrelated tone sounding through their headphones.

However, they wanted to prove their point further so they did a second experiment without the white noise. They thought that maybe the presence of white noise could possibly cause subjects to actively ignore all noise during the entire experiment. By taking away the white noise from the headphones, the presence of sound (versus natural silence) should be easier to detect and therefore be more noticeable. They found that, again, when the participants had the more dauntingly visual task of detecting the subtle difference in the length of the arms on the cross, they were a lot less likely to notice the beeping sound being played through the headphones, even in the absence of all other sound. So again, if a task takes a lot of visual concentration and attention, it can cause a decrease in auditory awareness. Now you think they would stop there, but Macdonald and Lavie took it to the next level once more.

In experiment 3, they sought to eliminate the possibility that those who were on the low perceptual load team were a little aloof during the experiment and those who were on the high perceptual load team maybe were a little more motivated, engaged and attentive because of the nature of their work being a little harder. So they made it a length only discrimination task where each person was asked nothing about color, only which arm of the cross was longer. Sometimes the difference in lengths between the arms of the cross was grossly obvious, other times it was subtle. They also increased the number of trials presented. Macdonald and Lavie found that still, those with a higher perceptual load (distracted with determining a more subtle difference in arm length) heard the sound less often than those who had the easier visual task of the more grossly obvious difference in cross arm length. Their results were “not as robust” but they were still there.

More studies need to be conducted on inattentional deafness to truly see how it affects our everyday lives. Macdonald and Lavie have concerns about inattentional deafness and driving a motor vehicle stating that if people were “less likely to notice an auditory alarm while engaged in a high-visual-load computer task, [then] the sound of a car horn while attending to a visually loaded billboard” also might pose a problem. Safety out on the roadways is definitely a concern.

Perhaps another interesting modification to the study would be to replace the tone sounding through the headphones with a person’s voice saying a word. Maybe a bizarre word that you wouldn’t just happen to overhear in the laboratory like zebra or halloween. Would the participant be completely unaware of human speech like it was of the tone when engaged in a highly visual task?

After researching this topic, I know I will be practicing more patience when I catch someone not listening to me. It may not have been intentional. And also I pledge to put down the smartphone and have some real “face-time” with the person sitting right across the table from me the next time I’m out for coffee. After all, they are deserving of my undivided attention. My emails, texts and tweets can wait. Unless of course I see a moon-walking bear, then all bets are off, sorry guys, I have to tweet pic that.

Additional tests of your visual awareness:

The Colour Changing Card Trick (by Richard Wiseman/Quirkology):

Test Your Awareness: Whodunnit? (by dothetest.co.uk ):

Also, check out the fun book by Chabris and Simons, The Invisible Gorilla: How our Intuitions deceive us.

Photo Credits: Man with glasses (Matt Jeacock /istockphoto), i-distractions and Author pic (Erica Angiolillo/Gotcha! by Erica), Bear (Trine de Florie /stockxchg photo).

References:

Boss, M. Caggiano, J. Hyman, I. McKenzie, K. Wise, B. (2010) Do You See the Unicycling Clown? Inattentional Blindness While Walking and Talking on a Cell Phone. Applied Cognitive Psychology. 24:597-607.

Chabris C. and Simons, D. (2011) The Invisible Gorilla: How our Intuitions deceive us. New York: Crown Publishing Group.

Macdonald JS and Lavie N. Visual perceptual load induces inattentional deafness. Atten Percept Psychophys. 2011 Aug; 73(6):1780-9. doi: 10.3758/s13414-011-0144-4

Cheryl Murphy About the Author: Cheryl G. Murphy is an optometrist and freelance science writer living and working in New York State. She began writing about vision science on her blog,Science Hidden in Plain Sight, in 2008. Links to her previous contributions to Scientific American’s guest blog can be found here. Follow her on Facebook or Twitter. Follow on Twitter @murphyod.

The views expressed are those of the author and are not necessarily those of Scientific American.






Comments 8 Comments

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  1. 1. murphyod 8:54 am 01/18/2012

    Here are the missing links to the article:

    Visual Awareness Test (by dothetest.co.uk):
    http://www.youtube.com/watch?v=Ahg6qcgoay4

    Color Changing Card Trick:
    http://www.youtube.com/watch?v=voAntzB7EwE

    Test Your Awareness: Whodunnit?
    http://www.youtube.com/watch?v=ubNF9QNEQLA&feature=youtu.be

    Link to this
  2. 2. Cogitari 12:27 pm 01/18/2012

    Once, I was working with my boss trying to get a balky piece of equipment working when he suddenly got up and went outside. Later, when he came back in, I found out that there had been a large explosion which turned out to have been at the local armory some ten miles away. He could not believe that I had heard nothing. I wonder if this is another example of liberal/conservative difference with the conservatives more focused on dangers (something unexpected) and liberals more focused on benefits (like getting the equipment working).

    On the other hand, men not paying as much attention to what women say as they do to other men, is another matter entirely. I did not believe this when I first read about it, but then I started seeing it in meetings all the time. I am still not sure if this is something many men do or only a select few. I would love to see a scientific study on this.

    Link to this
  3. 3. murphyod 12:44 pm 01/18/2012

    Cogitari- thank you for the comments, very odd how with two people under the same conditions (and assuming both have “good hearing”) one can hear something off into the distance while another cannot. If you subscribe to the theory of inattentional deafness that Macdonald and Lavie studied, then perhaps we could conclude that you were a little more focused on your part in repairing the equipment whereas your boss was not and therefore more easily distracted by outside noise?

    There are so many interesting studies that could branch off of the one I spoke about, many having to do with the human voice and if that too is ignored like the beeping sound. Then branching further into your point of the possibility maybe one is more likely to lend auditory awareness and attentive listening to someone of the same sex. Who knows! It’ll be intriguing to see how this all plays out as new studies arise.

    Cool example and point, thanks.

    Link to this
  4. 4. biggus56 8:01 am 01/20/2012

    In the last video, I spotted 1 real change and 1 fabricated (by me) because I was looking for them. So, even with raised expectations, my score was dismal.
    Therefore, I have to ask: how do film nerds spot continuity errors with such uncanny accuracy? Do nerds have different brains, and how much of a film’s plot do they remember, as opposed to the detail?
    (I admit to some nerdish tendencies myself, so I hope no one’s offended.)

    Link to this
  5. 5. murphyod 2:02 pm 01/20/2012

    Biggus56- You are not alone, I missed all changes except the flowers in the ‘whodunnit’ video the first time I watched it. I was so distracted looking for ‘tells’ on the faces of the people being interrogated to worry about set changes. That is what I find so fascinating about these visual awareness/inattentional blindness and change blindness tests…you go into it almost expecting a trick and wanting to outsmart the test but really they have you hook line and sinker focusing on the wrong details and missing the obvious! They are a lot of fun though.

    Good question, since these visual awareness tests are usually presented as videos, would someone who edits video on a regular basis be more aware of something amiss? Hmm…

    They have done visual awareness tests outside of the lab on a college campus though. They actually walked up to people to do an impromptu awareness test on them, assessing if the average person would notice a person-change. If someone stopped to ask you for directions or for help reading a map, would you notice if that person was switched out for someone else while you were busy reading/pointing to and figuring out the map? Really cool idea by Simon and Levin called “the Door Study” 1998. By one of the same researchers from the original invisible gorilla study.

    Here is a link, scroll down to “the Door Study” video! =)
    http://www.theinvisiblegorilla.com/videos.html

    Link to this
  6. 6. furpaw 11:33 am 01/21/2012

    That’s interesting, neat research, but I would have said that “inattentional deafness” had been demonstrated in the 1950s and 1960s in the dichotic listening and shadowing experiments by Colin Cherry, Donald Broadbent, Anne Treisman, and others. They didn’t call it that; they called it “selective attention.”

    Link to this
  7. 7. murphyod 9:03 pm 01/25/2012

    @furpaw- Thanks! You have definitely peaked my interest, I would love to read about their experiments and compare to what’s being done now by Macdonald and Lavie. Thanks for the tip and names of experimenters, I am interested to learn more!

    Link to this
  8. 8. psyscott 2:57 pm 01/28/2012

    INATTENTIONAL DEAFNESS IS NOTHING NEW
    It’s very naive for Cheryl Murphy to say that “Researchers in the United Kingdom have demonstrated for the first time a phenomenon known as inattentional deafness.”
    As furpaw suggests (above), there’s nothing new about Macdonald and Lavie demonstration of “inattentional deafness” beyond the clever title. It is true that the studies in the 1960s by Colin Cherry, Donald Broadbent, and Anne Treisman did not demonstrate the cross-modal effects of attentional load. However, many other previous studies have demonstrated and studied cross-modal processing limitation more thoroughly than Macdonald and Lavie. This phenomenon is fundamental to current theories of an amodal capacity to working memory capacity in terms of a limited focus of attention. For example, see:
    Saults, J.S., & Cowan, N. (2007). A central capacity limit to the simultaneous storage of visual and auditory arrays in working memory. Journal of Experimental Psychology: General, 136, 663-684.

    Link to this

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