The Cocktail Party Effect
For psychologists the 'cocktail party effect' is our impressive and under-appreciated ability to tune our attention to just one voice from a multitude. At a party when bored with our current conversational partner -- and for the compulsive eavesdropper -- allowing the aural attention to wander around the room is a handy trick.
Perhaps only the most recidivist eavesdroppers are aware how special this ability is. But even they might be surprised -- and worried -- by just how much we can miss in the voices we decide to tune out.
Close your eyes and concentrate
Our ability to separate one conversation from another is beautifully demonstrated in a classic study carried out by Colin Cherry, then at Imperial College London (Cherry, 1953). Cherry used the simple method of playing back two different messages at the same time to people, under a variety of conditions. In doing so he discovered just how good we are at filtering what we hear.
In the first set of experiments he played back two different messages voiced by the same person through both ears of a pair of headphones and asked participants to 'shadow' one of the two messages they were hearing by speaking it out loud, and later by writing it down.
To accomplish this task, Cherry reports, participants had to close their eyes and concentrate hard. When doing this they could, with effort, and while hearing the clips over and over again, separate one of the messages from the other.
With the two voice presented together, as though the same person were standing in front of you saying two completely different things at the same time, this task appears to be very hard, but still possible. Pushing participants further Cherry found he could confuse listeners, but only by having both messages consist entirely of nonsensical platitudes. Only then were participants unable to pick apart one message from the other.
Receiving you loud and clear
The real surprise, though, came in the second set of experiments. For these Cherry fed one message to the left ear and one to the right ear -- and once again both messages were voiced by the same speaker.
Suddenly participants found the task incredibly easy. Indeed many were surprised how easily and accurately they could tune in to either one of the messages, and even shift their attention back and forth between the two. No longer did they have to close their eyes and furrow their brows - this was much easier.
What participants were experiencing here seems much closer to most people's experience of picking out one conversation from a multitude. At a party people are arrayed all around us and their conversations come from various different directions. We seem to be able to use this information to reject all but the one in which we are interested.
I'm sorry, what were you saying?
Although we are fantastically good at tuning in to one conversation over all the others, we seem to absorb very little information from the conversations we reject. That's where it can get embarrassing.
Cherry found his participants picked up surprisingly little information presented to the other, 'rejected ear', often failing to notice blatant changes to the unattended message. When asked afterwards, participants:
- could not identify a single phrase from the speech presented to the rejected ear.
- weren't sure the language in the rejected ear was even English.
- failed to notice when it changed to German.
- mostly didn't notice when the speech to the rejected ear was being played backwards (though some did report that it sounded a bit strange).
Across all the different conditions tried there were only two aspects of the speech to the rejected ear the participants could reliably identify. The first was that it was speech compared to a tone, the second was when the speaker suddenly changed from male to female.
This doesn't bode at all well for people with a habit of tuning out of conversations when they lose interest (you know who you are!). If you really are listening to someone else it's likely you won't hear a word of what's being said to you directly. One study has found that two-thirds of people don't even notice when their own name is slipped into the unattended speech, while those who do notice are likely to be of the extremely distractable variety (Conway, Cowan & Bunting, 2001).
You have been warned!
→ Part 1 of a series on the psychology of attention →
[Image credit: andruby & yasu2909]
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I find this interesting.
It never occurred to me that each one of my ears is a separate microphone, and that these two inputs can process different information separate from each other. I can switch one on, and the other off.
I just assumed that I use both ears equally, and that both ears hear the exact same thing.
I'm sorry, Did you say something?
It never occurred to me either that my ears were separate microphones until I had sudden onset hearing loss last year.
I had always been adept at screening out what I didn't want to hear. My left ear was almost completely gone and my right was diminished. I lost all ability to tune ANYTHING out! I wasn't left in silence but in chaos that I had never experienced before. My brain could not sort by distance or volume. I could hear the waitress asking me to order but could not understand her because a conversation in the next room was more prominent in my brain.
It's clear that it takes both ears (properly connected to the brain) to pay attention and to focus attention. Now that my hearing is mostly restored, I can tune out most unwanted sounds if I concentrate. But my voice comprehension has never been the same as before the incident.
We take this ability for granted—tuning out. But it is essential for mental health.
amazing article. I, for one, can't really focus on one conversation in a bar. not sure why.
I have always found it extremely difficult to tune into a single conversation. Maybe I'm one of the very easily distractable people.
Our own inner conversation also can become a distraction in these situations where we end up cycling between what we are thinking about a particular conversation and the ones we are trying to follow. Phew!
I am wondering why so many kids are being diagnosed with ADD when paying attention is a choice in most cases.
When i was younger the doctor told my mom i had "selective hearing" and not to mention i was hard of hearing...but yeah I've heard about this when i was younger because of him telling my mom that.
So it is really real, and you would be surprised at what you miss when you don't want to hear someone, just how much you can tune them out almost completely.
I guess it all makes sense now.
Kat,
I'm not sure but it seems that you are saying that there that attention is only consciously controlled. This however is not true, attention is a psychological element which is composed of numerous overlaping and compeating mechanisms. There is an element which is under conscious control and develops with age. But there are also other elements which capture our attention against our will, like when a loud noise captures our attention. So if you take the newborn infant, their focus of attention is entirely dictated by the environment. As they grow they will develop an ability to control their attention. Children with ADD are delayed concerning the development of this skill. It is not the child's fault and they are not just choosing to have a poor attentional focus.
I study memories, and selective attention, or focusing on a selected portion of sensory input, controls what information moves on to short term memory and so long term memory. Poor focus may not be intentional especially in children, but I also study the Bible. I find it interesting that the Bible encourages us to paying attention to how we listen.
On a slight tangent i also find this works with music. When listening to a piece of music, i find i can pick out different instruments in preference to others, the bassline, for example, by 'tuning in' my ear to the sound of the bass. It may take a few moments but then the bass will appear loud and clear from the mix. I can then tune back out to the guitar or drum and the bass will fade back into the song as a whole.
Bronson,
I didn't mean to sound harsh or critical. I had a delayed onset of Post Traumatic Stress Disorder in my adult life. I lost procedural memories. I have a question for you, " what is the difference between learning a task that requires attention to motor skills (like riding a bike), and performing a learned response that requires paying attention to the teacher (like raising your hand in class)?"
I found this article quite intriguing. This past week, I had an ear infection that (for about 10 hours yesterday) rendered my hearing in that ear completely deaf. Similar to Diana, though to much less of an extent, I began to hear large amounts of background noise (especially when I went to walk my dog and heard lots of leaves rustling, etc.). Also, when I was chewing food, the crunches from it seemed about four times as loud as usual.
PS: Loved the bullet points about the changes people didn't notice...switched to German, haha.
This article was interesting for me since i was born partially deaf so have always worn hearing aids. With these i can hear everything clearly and have no problems in all situations except when i need to follow a conversation in loud environments with others talking around me. I think wearing hearing aids hinders the ability to specify and differenciate between conversational groups leaving me quiet and often bored at pubs etc which is otherwise out of character.
Anyhow, i'd love to be able to do this so make the most of it guys.