It has happened to all of us that, when we were out partying and in a disco, we approached someone to talk to them and, despite the noise, we more or less understood what they were saying.

This, which seems surprising, has a name, and coincidentally is very much related to the field of leisure. The cocktail party effect is to be able to differentiate between the sound that interests us and those that can be a distraction .

This effect has its importance at the evolutionary level, and that is why it has been addressed experimentally. If you want to know more in depth what it consists of and what theories have tried to explain it, we invite you to continue reading this article.

What is the cocktail party effect?

The cocktail party effect is a phenomenon that consists in focusing the auditory attention on a particular acoustic stimulus, while trying to filter and eliminate the rest of the stimuli that can act as distractors .

The name of this phenomenon is quite representative of the effect, since, if we think about it, at a party, when we are talking to a guest, we try to filter out what he is saying and ignore the music and other conversations that may be going on simultaneously, forming the background.

Thanks to this phenomenon, we are able to differentiate between the voice of the person with whom we are holding the conversation and that of the rest of the people who may be forming the acoustic background of the environment in which we are.

This same phenomenon also allows us, without being totally concentrated in other conversations, to be able to catch our attention when a word that is important to us is mentioned , such as being called by our name.

Neurological bases

Research has tried to find out what the neurological basis is behind the cocktail party effect. This phenomenon has a great evolutionary advantage, since it allows us to differentiate between the sound stimuli that interest us from those that can act as distractors. Due to this, it is implicit that there must be some mechanism at a cerebral level that gives an explanation .

Auditory attention occurs mostly in the upper temporal gyrus of the right hemisphere, where the primary auditory cortex is located. There is a whole neural network involved in the process of localizing sounds from the environment. This network, which is frontoparietal, includes the lower frontal gyrus, the upper parietal sulcus and the intraparietal sulcus. These areas are involved in attentional change, speech processing and attention control.

The cocktail party effect works when the person has full functionality of both ears . That is, for this phenomenon to occur properly, it is necessary for the person to have binaural hearing in good condition. Having two ears makes it possible to locate up to two sound sources satisfactorily, in addition to attributing distance and acoustic properties to them.

Theories of Attention

Not all acoustic information a person may be exposed to is processed by their brain. Many theories have been proposed to try to explain the fact that, in an environment where multiple sound stimuli are present, we are able to distinguish between what we are interested in and what is in the background.

Below we’ll look at some of the more important proposals that have tried to explain the phenomenon of the cocktail party effect:

1. Broadbent

Donald Broadbent, performing several experiments with dicotic listening , observed that participants were more likely to remember those sound stimuli to which they had consciously paid attention compared to those to which they had not.

For example, if they were given two headphones and asked to pay more attention to what was heard through one of the two speakers, the participants would usually say exactly the same thing that they had heard through one of the two speakers.

Based on this, Broadbent proposed that attention, and in this case hearing, had a kind of filter , that is, we consciously select what we want to hear from what we do not want to pay attention to.

The way this filter works would be the following: first, the information enters the brain through the ear and associated nerves, then it is stored in the sensory memory so that, afterwards, we pay conscious attention to it and select what interests us.

Before the information is processed, the filtering mechanism only lets the information that is important go to higher processes. Once this has been done, goes into working memory, where it will be used for the ongoing conversation or, if attention is being paid to something, it will be stored in long-term memory.

However, later, Gray and Wedderburn brought the Broadbent model to the ground. They carried out an experiment with dicotic listening as well, only this one had certain peculiarities. The participants were made to hear in one ear the phrase ‘Dear, one, Jane’, while in the other they heard ‘three, Aunt, six’. Participants remembered hearing a mixture of both phrases, most commonly ‘Dear Aunt Jane’ instead of the numbers.

2. Treisman

Anne Treisman proposed the model of attenuation . This model maintains that the information, once it has passed through some filters, is not completely blocked, unlike what is inferred from Broadbent’s model.

Instead of being completely ignored, the uninteresting information is attenuated, that is, it loses its strength, but it is still there. This means that, because of an oversight or distraction, it can later move on to higher attention processes.

To better understand this idea: if we are talking to someone at a party, it is normal that we do not pay attention to what others are saying. But, if someone mentions our name, even though we weren’t paying attention at first, we’ll probably turn around and see who said it. This is because our name, no matter how muted in the background, is something that has great meaning for us.

3. Kahneman

Finally, in Daniel Kahneman’s model for auditory attention, a difference can be noted from previous models. Unlike Broadbent, Kahneman does not speak in terms of filters but in terms of capacity. Attention is seen as a resource that has to be distributed among several stimuli .

Attention is more efficient the better the person’s arousal, i.e. if the person is low on energy and reduced in concentration, his attention will also be lower.

This means that the more tired you are, the less likely you are to get the cocktail party effect, making it very difficult for you to distinguish efficiently between the conversation you are having and the other acoustic stimuli.

Cocktail party effect and hearing loss

The cocktail party effect only occurs if you have binaural hearing, i.e. you hear correctly in both ears. Those who are totally or partially deaf will have a significant difficulty in locating sound sources in space, as well as distinguishing between what their conversationalist is saying and the sounds coming from the background.

For this reason it is common that people who have an affected ear find it more difficult to discriminate against the background noise ; they are more distracted by the interference in the environment, as well as not attending satisfactorily to the conversation they are having.

This is why common situations such as going out to a noisy place or a family gathering, where several conversations can take place at once, are really frustrating situations for those who suffer from some kind of hearing impairment. They find it difficult to focus their hearing attention on the stimulus they really want to hear.

Bibliographic references:

  • Broadbent, D.E. (1954). “The role of auditory localization in attention and memory span”. Journal of Experimental Psychology. 47 (3): 191-196. doi:10.1037/h0054182.
  • Gray J.A.; Wedderburn A.A.I. (1960). “Grouping strategies with simultaneous stimuli”. Quarterly Journal of Experimental Psychology. 12 (3): 180-184. doi:10.1080/17470216008416722. Archived from the original on 2015-01-08. Retrieved 2013-07-21.
  • Kahneman, D. (1973). Attention and effort. Englewood Cliffs, NJ: Prentice-Hall.
  • Bronkhorst, A.W. (2015) The cocktail-party problem revisited: early processing and selection of multi-talker speech. Atten Percept Psychophys. 77(5): p. 1465-87.
  • Toth, B., et al. (2019) Attention and speech-processing related functional brain networks activated in a multi-speaker environment. PLoS One. 14(2): p. e0212754.
  • Treisman, Anne M. (1969). “Strategies and models of selective attention. Psychological Review. 76 (3): 282-299. doi:10.1037/h0027242.