The Fallibility of Interpretation Sense Perception and Reliability

Mack Hutsell

Alex Liu, Paschalis Economou, Valeria Espinosa

Feb 1, 2017 - Feb 7, 2017

WOK Badge: Sense Perception

TOK Project: Test the McGurk effect but with a wider variety of sounds

For our project we decided to test the reliability of interpretation through a variation of the McGurk effect. We took audio clips of certain sounds and played them over videos of someone mouthing a similar, yet different sound.



Mack: For our project, we decided to do an altered version of the McGurk effect. We started out the project with the question, “To what degree are sense perceptions altered by our expectations”. We hope that this project shows how sense perceptions can be altered to a high degree because of different sense biases we hold. During this Kahoot, simply watch the video, and choose the choice that best represents what sound you heard. Do not discuss the answers with those around you and stay focused on the screen throughout the videos.

Valeria: So when we first started this project, we hypothesized that Sense Perceptions were easily altered by expectations. After playing around with many different vowel and consonant combinations, we decided that Sense Perceptions were able to be manipulated, but it was not easy. We settled on around 10 combinations that were effective most of the time, and decided to record video clips of Paschal saying these sounds and then quiz the class to test our hypothesis.

Alex: As the results of the quiz indicate, our sense perceptions are not always guaranteed to be accurate and often our senses confuse each other. For example, after hearing the sound “bah” with your eyes closed, you could most likely realize that the sound bah was being made. However, when your eyes interpret the sensations of the mouth making the motion “Fah” as the sound of “Bah” is played, your eyes begin to weigh in, and sometimes overrule your ears. This is key in understanding in how our Sense Perceptions allow us to perceive the world.

Mack: The McGurk effect was originally discovered in 1976 when researchers were attempting to study infants’ change in perception of language based on the developmental stage they were in. This effect takes place “because of the brain's effort to provide the consciousness with its best guess about the incoming information.”

Valeria: This leads back to Sense Perception. We believe our brains to be absolute and knowing regarding interpreting the world around us, however it is clear that our brain is simply giving us its “best guess” when given sensation to analyze.

Mack: Our biases play a large role in our interpretation of the environment around us. We use previous knowledge so that we are able to fill the gaps in our surroundings without much brain power dedicated to analyzing those sensations. However, these biases often impact how we perceive the world. One effect that makes the McGurk effect a lot stronger is the expectation of a certain word in a sentence. For example if it is a sentence you hear often, “Hello, how are you”, if a different audio clip was played that said “Hello, how are new” or “Hello, how are few”, and yet the visual clip showed someone mouthing you, the McGurk effect would be very strong. We use our biases to make sense of the world. If we never had any biases to operate off of, the world would be consistently and never endingly complex.

Alex: We started with the question, “To what degree are our sense perceptions shaped by expectations”. We hope that through this experiment, you are able to tell that Sense Perceptions, especially when dealing with multi-modal sensations (Using several senses to interpret information, are unreliable and subject to our biases gained through prior experiences.

Mack: Now, from this experiment we can gain many insights into something deeper than simply our sense-perceptions. The fact that our biases so easily, and subconsciously, affect our interpretation of the world suggests that our biases may entirely shift the way we gain knowledge, and therefore impact our ability to truly understand the world. In fact, many of the Theories of Reality discussed in Chapter 5 are placed in danger because of this experiment. For example: Common Sense Realism. This theory operates around the fact that the way we perceive the world mirrors the way the world actually is. And Phenomenalism, based on empiricism, is also threatened. If we can not trust our senses, which is clearly shown in this experiment, how can we trust that we can only verify something if we have witnessed it?

Valeria: The McGurk effect disproved several theories, and leaves us with many questions, to end the presentation, consider this: “If we can not verify the reality of our world through our senses, how can we verify anything?”.


Through our testing of the class we found that they were only able to accurately choose the correct answer in 40/112 answers, or about 36% of the time. We successfully demonstrated the fallibility of interpretation.

Chart for Video

Sense Perception Journals:


Today we took the TOK quiz (which I had to retake), then we discussed how we were going to do our project on sense perception. We talked about possibly doing a McGurk effect video. Where we play the same sound over videos with different mouth movements, causing people to hear different sounds. We then talked about possibly doing a video that purposely distracts the viewer.

I think we should record a card trick and show it to the class. We then ask questions about when they were mislead. However in the video we have something else going on behind the card trick that is along the same lines as the gorilla walking behind the basketball court. We will be able to draw conclusions about Sense Perception through both the card trick and the gorilla. It will demonstrate change-blindness. This project should be able to demonstrate our knowledge and understanding of how Sense Perception is fallible.



Today we need to plan out our project. We have the idea of doing magic and doing a project on distracting Sense Perception, but we do not have a concrete plan for accomplishing this yet. Today I want to create a plan and begin to complete our project. This should set us up to be able to finish on Monday. By 12 I want to know exactly what we are going to do. I also want us to do a little more research on what exactly sense perception is. Our definition is good, but a full understanding is going to be necessary to make a good project.

During Class: How does bias and sensual conflict affect our sense-perception?

After Class:

Hypothesis: I believe that the multiple conflicting sensations will confuse our brain and cause it to incorrectly interpret what it is hearing.

What did you learn today?

I learned many things today. We started out debating how to do our project and we ended with deciding to do an alternative version of the McGurk Effect. We spent around 15 minutes before deciding that we would go through many different sounds and experiment to see which sounds could be overlayed other mouth motions and be convincing. We did a lot of experimenting and we now have a better understanding of which sounds work better with different mouth expressions.

What did you accomplish?

We accomplished the bare-bones research required for our project. We were able to experiment most of the sound and mouth combinations. We also accomplished creating a hypothesis and finding a question. These are both necessary for completing our project.

What do we need to accomplish?

We need to complete experimenting.

2/3/17: Elective Reading Journal

"How can going blind give you vision"

This TED talk is incredibly insightful. The quote, "Worse than being blind, is having no vision" by Helen Keller is necessary for understanding this chapter. Sense Perception, chapter 5 in our TOK textbook, discusses Theories of Reality, our perception of the world, and other possibilities of sensing the world; however, more important than this is our outlook on life. We can have any amount of knowledge about how we perceive the world, but if we are unable to use this knowledge to better our lives and the lives of people around us, then we are wasting our time.

This TED talk explains how Isaac was diagnosed with a condition that would leave him blind. When he first received the news, he was devastated as he equated blindness with lack of use. This clearly shows how much emphasis we place on sight: so much so that the lack of sight equals a disability.

The TED talk provides the outside perspective which is important in analyzing the value of this chapter. Our senses are an important Way of Knowing, and they provide a medium through which we can understand the world, but without further interpretation of this knowledge, it is a meaningless understanding of the world we possess.

This TED talk helps answer the question: "To what extent is our understanding of the world shaped by our sense perception?"

From this TED talk, it is clear that we allow the way we perceive the world, and others abilities to perceive it in the same way, as a judgement of how valuable they are. This is only because of how our Sense Perception shapes our understanding of the world. I believe this shows that our understanding of the world is shaped to a large extent.


Overall this project was incredibly helpful in helping me understand what Sense Perception meant in terms of understanding reality and therefore knowledge. We did a good job of organizing our roles and completing them on time. This allowed us to be ready to present on the day of. However, we did not do a good job of making sure our individual parts added up to less than seven minutes. I think this is partially related to the copious amount of information that is essential to the explanation of this project, however we also did not budget our time appropriately.

- Can we prevent our biases from giving us a false representation of the world?

- If we can not trust our sense perceptions to give us reality, can we ever be certain of our understanding of reality?

- How does someone's understanding of reality reflect on their experiences/biases gained in life.

Extension Proposal:

Essential Question: "If we can not trust our senses to show us reality, can we ever be certain of what is real?"

This question accurately reflects the fears that come from reading Chapter 5. It is not answerable, however it is necessary to think about because it provides a scope and incredible depth for the information presented in the chapter.

A good source would be The Prison of Your Mind by Sean Stephenson. This TED talk would very well in tandem with the TED talk by Isaac Lidsky discussing blindness and vision. Both rely on the same founding principle of correcting misunderstandings in perception of daily life.


Created with images by crescentsi - "illusion"

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