What is the McGurk Effect? Understanding Illusory Perception

Last Update on October 26, 2021 : Published on October 26, 2021
McGurk effect psychology

The McGurk effect is all about your perception. It is a perceptual phenomenon. If you divide the speech into two (just for better understanding), there are two parts, visual and auditory. Visual speech can be the lip and mouth movement and auditory is the words and sounds that our lips and mouth produce.

What happens in the McGurk effect is that the visual and auditory speech don’t seem to be in sync. Since it is a perceptual condition, there is nothing wrong with the person who is speaking. It’s our perception that is faulty.

Did you know the McGurk effect was found accidently?

Harry Mcgurk and his assistant Mcdonald were conducting a study on language and it’s perception during the developmental stages in children. That’s when they accidentally discovered this perceptual or illusional phenomenon.

What is the McGurk Effect?

McGurk effect

The Mcgurk effect is when we think that the lip movements (visual speech) of the one who is  speaking seem oddly different from the words that are coming out of their mouth (auditory speech).

Also read: Understanding The Stages Of Effective Listening | Why You Should Practice Active Listening

Let me simplify it for those you might have never experienced before or do not suffer from this phenomenon.

When we are watching a movie and you forward/rewind a few minutes in the movie, the audio and visual start to run at different times. What you see then, the actor’s lips don’t sync with the dialogue anymore. That’s somewhat similar to what the Mcgurk effect may feel like.

Harry Mcgurk and his assistant discovered the Mcgurk effect in 1976 when they were conducting a study on children and their perceptions.  They said that this effect is basically an illusion which is caused because of the interaction between the auditory and visual speech.

Want to know why the Mcgurk effect may occur? Here’s what Makes Mcgurk effect happen in real life…

Factors Responsible for the Mcgurk effect

Broadly speaking, there are two factors responsible for Mcgurk effect to occur:

  1. Internal factors
  2. External factors

Internal factors cause the Mcgurk effect are:

1. Alzheimer’s disease: According to a study conducted in 2007 by Delbeuck, colette and Linden people suffering from Alzheimer’s disease did show the presence of Mcgurk effect when studies with a controlled group. This means that Alzhiemer’s can sometimes be responsible for experiencing the Mcgurk effect.

2. Aphasia: Youse, Cienkowski and Coelho in 2004 found out that adults who are suffering with Aphasia did show signs of Mcgurk effect. Hence, Aphasia can also be responsible for this illusion to occur.

3. Specific language impairment: Norrix, plante and boliek (2007) conducted a study where they found that those who have Specific language impairment showed a strong presence of Mcgurk effect when compared with people who do not have Specific language impairment.

Also read: 20 Signs For You To Know What Does A Good Therapist Look Like

External factors that cause the Mcgurk effect

1. Visual distraction: According to various researches, if your visual attention is ont completely on the speaker’s lips then the Mcgurk effect is less likely to happen to you. Therefore, when you only and only focus on the lip movement then you’re most likely to experience the illusion.

2. Familiarity: You are less likely to experience Mcgurk Effect if you are familiar with the person you are talking to. It might happen to you when you are in a conversation with someone who is unknown to you.

3. Tactile diversion: if you touch something or are in contact with something physically, you are less likely to experience Mcgurk effect and if there is no tactical diversion then you might experience it.

Also read: Hippopotomonstrosesquippedaliophobia: Can Unusually Long Words Trigger Fear In People?


The Mcgurk effect is a kind of illusion that makes you feel like the lips might be saying something else and your words might say a completely different thing. There may be various factors responsible for you to experience this perceptual phenomenon which are listed above.

I hope you found this blog interesting. If you want to read more such blogs you can visit calmage.com. Do share it with your friends and family and do let me know if you experienced the Mcgurk effect in the comment section below!

Thank you for reading this blog!

Stay safe and take care of yourself.

About The Author

Kirti Bhati
Kirti Bhati

I am an English literature (major) and psychology (minor) graduate from St. Bede’s College, Shimla. Postgraduate in Clinical psychology from IIS University, Jaipur. She has published a Research paper on Music therapy in the military population and Workplace stress in a national seminar conducted by Fortis hospital (gurugram) and international seminar conducted by St. Bede’s College, Shimla, Respectively. Authored a dissertation work on ‘effect of social media addiction on the mental and physical well-being in adolescents’ Currently working at calm sage as a writer.

Leave a Reply

Your email address will not be published. Required fields are marked *

As Seen On