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The Limitations of Human Perception, Part 1

Bruce-willis

Let’s do a thought experiment. The point of it will become clearer in future posts, but for now bear with me.

Imagine you went to another planet and met the natives there. By use of special machines, you were able to communicate with them.

An interesting thing you realize about these natives is that they have no noses. The dominant species of this planet has evolved to have no noses and has never had a sense of smell. They have never even developed language to cover concepts related to smell. There’s no equivalent word for odor, stinky, aromatic, fragrant, inhale, breathe, or any other words that can be linked to a nose and a sense of smell.

Also, since flavor comes from one’s sense of smell, there are no equivalent words for tasty, delicious, flavor, flavorful, and so on. The sense of taste actually has to do with the sensations that food creates on our tongue via the taste buds. Flavor on the other hand comes from our sense of smell. To illustrate, if you pinch your nostrils really hard and then try to eat something like a lemon or a piece of bacon, the appropriate taste buds on your tongue will still tingle to indicate whether the food is sour or if it’s rich and fatty, but the food will register no flavor. 

How would you describe the sensations of scent and flavor to this species? Since all the information they’ve ever known in their lives has related to the senses of sight, taste bud tingles, touch, and hearing, you would be forced to try to convey the concept of smell using language and concepts related to those four senses. How could you pull it off?

Or how about if the species had evolved to have no eyes and therefore no one could see or was ever able to see. How would you describe the concept of sight to them, or give a visual description to them of something? Could you describe the color blue or green to people who have no idea what a color is in the first place?

But the irony is, the species with no sense of smell, who have never had a sense of smell, the would have no idea if you didn’t tell them that they were missing out on something. They would think that the four remaining senses they used to perceive the world around them was giving them a complete sense of objective reality. They would have no idea that there is a whole universe of potentially useful information right in their midst, all around them, that they can’t perceive and take in.

Over the history of the existence of their species, they would likely evolve other ways to compensate for the lack of ability to smell. Their eyes perhaps could evolve to the point where they can tell if food is spoiled simply by looking at or touching it. Their taste buds could evolve differently. Any of their remaining senses could become quantitatively or qualitatively different to compensate for their inability to smell.

So think of human beings. We perceive and explain the world using language and concepts limited by our five senses. We often believe that the information obtained using these five senses gives us an objectively accurate and complete representation of reality. Who knows how much potentially useful information is floating around us right in our midst, but invisible to use because it falls outside the realm of our five available senses, just like the aliens in my example live in a world of smells that they are oblivious to?

The point I’m trying to make is, what we perceive to be objective reality is not actually reality, but is an approximation of reality constructed using what limited tools of perception we currently have available to us. We’re going to be revisiting this topic a lot, so it’s important to understand it.

One example I can think of us happened in Haiti to my family during the recent earthquake. My family members who survived it all told me that before each tremor happened, the dogs and other animals would flip out and run for cover. I found this fascinating and started doing research on it, and sure enough it’s true, as you can read here and here. Some people claim that their animals started getting agitated days, weeks, or even months before natural disasters like earthquakes and tsunamis. A video about this can be seen below:

Scientists aren’t sure whether this is because of dogs having an extra-heightened version of a sense humans already have, like hearing, or because of dogs having a whole extra sixth sense that humans don’t have at all. If it’s the latter, you can see the difficulty scientists are presented with. Trying to describe a brand new sixth sense using our current language, which relates to the five senses of sight, smell, taste, touch, and hearing, would be like my thought experiment of trying to explain smell and scent to a species using language only related to the senses of sight, taste buds, touch, and hearing.

Just like the hypothetical species wouldn’t even have the cognitive tools to even properly process scent concepts, if dogs do have a sixth sense that we don’t know about, we as humans may lack the cognitive tools to properly process whatever that sense is, so we may never end up being able to comprehend or explain it.

Which leads to my next point about the limits of human perception: in addition to our five senses, human perception is limited by the established cognitive framework, thinking habits, and processing capabilities the human brain has developed over your lifetime. The human brain is the central area where much of our sensory intakes are perceived, processed, interpreted, and responded to. The limitations of how our specific brains work lead to limitations in how well we can process and perceive reality via the sensory information we take in. These cognitive limitations on reality perception play a big role in our personality conflicts, our susceptibility to logical fallacies and con artists, and the cognitive distortions that often cause us problems in our daily dealings.

The ways in which the features of our brain contribute to our limitations in perceiving objective reality will be the focus of the next installment of this series.

12 Responses to “The Limitations of Human Perception, Part 1”


  1. I’m not sure about the lack of cognitive tools – for example, we cannot perceive radioactivity, but we can understand it; in the same way the natives from other planet might easily understand that some objects release molecules that are detectable by our noses. Surely, they won’t know what it’s “like” to smell, but it won’t appear supernatural at all.
    I understand it’s not the key point here though and I’m looking forward to future development of this series.


  2. “The point I’m trying to make is, what we perceive to be objective reality is not actually reality, but is an approximation of reality constructed using what limited tools of perception we currently have available to us.”

    It’s emotions that *really* get you on this one. When I realized that I somehow kept dating the same kind of girl again and again, I started trying to change my emotional responses to that kind of girl (things always didn’t work out with her – it wasn’t nearly as bad as the dating horror stories on the internet, but I knew I didn’t want to keep doing it). Combined with social dancing, and an ability I’ve always had to alter my emotions, after a few years I was able to change my emotional reaction to that kind of person.

    But what was really trippy was that in the process – I found that NONE of my emotions were 100% “real”. What I mean is – there are certain emotions and feelings that you feel as “reality” or that have always just been there, but it’s possible to remove or alter them – and it can make you feel INCREDIBLY bizarre.

    Other things would happen where I could change emotion reactions – it’s like how you see a girl a ways off, and you feel like “woooow…she’s amazing looking”, then she gets closer and you can see her better and it turns out she’s much different looking than you thought and suddenly you feel very different about her looks? It’s like that with…everything.

    At some point it become apparent that ALL of my perceptions were perceptions. They’re still “real” – the wall in front of me is still a wall – but it’s kind of bizarre how much we think of “reality” is just the perception, and how much can be missing or altered (or even worse – the self-fulfilling prophecy where how you perceive it influences how it becomes, which mostly applies to social interactions where how you act changes how the other person acts).

    “in addition to our five senses, human perception is limited by the processing powers of the human brain.”

    I agree, but – it’s not the only thing.

    Sometimes the thing is not about the processing capacity, but how our perceptions have learned to interpet things.

    I mean a lot made of “processing capacity” before, but it’s also about the complexity of the patterns your brain has developed, the flaws (or just gaps) in those patterns in your brain, etc etc.

    I’ve altered my perception of people, and I can definitely say that there was a lot I was missing before – not because I didn’t have the senses to perceive it, but because my brain habitually ignored or didn’t have an interpretation for the signals for. The signals were coming in – the sense was there – and it wasn’t a matter of not having enough processing power. The info was just being thrown out – or habitually being interpretted in an innacurate way.

    Processing power is *also* an issue. But it’s not…it’s definitely not even close to the only issue…


  3. Paul:

    I agree, but – it’s not the only thing.

    Sometimes the thing is not about the processing capacity, but how our perceptions have learned to interpet things.

    I mean a lot made of “processing capacity” before, but it’s also about the complexity of the patterns your brain has developed, the flaws (or just gaps) in those patterns in your brain, etc etc.

    When I said “processing powers” (plural) I meant something similar to what you describe. But I realize it can seem like I’m saying “processing power” (singular) as in horsepower or capacity, like how you interpreted it. Your interpretation was totally reasonable, but not what I meant. I’ll change the language accordingly so no one else gets confused.


  4. Paul, I changed the language. Tell me if you find it more in line with what you were saying. Thanks.


  5. Re:
    “what we perceive to be objective reality is not actually reality, but is an approximation of reality constructed using what limited tools of perception we currently have available to us.”

    Are you saying that we know _objectively_ that the above is true?


  6. Good question Kate. ;)


  7. Great post Ricky.

    If the points you’ve made in bold are true (and I believe they are), then coming back to your original question of “how would you describe the sensations to this species?”, the answer is you couldn’t. Ever. With no common frames of reference, this just wouldn’t be possible.

    “If a lion could talk, we could not understand him” – Wittgenstein


  8. “Paul, I changed the language. Tell me if you find it more in line with what you were saying. Thanks.”

    Fyi, I reread it per your request, but it still sounds essentially the same to me. Looking forward to seeing where you’re going with it though!


  9. Ah well, the point is, I agree with what you said and meant what you meant, even though I may not be phrasing it correctly. Thanks for the feedback.


  10. It’s because dogs don’t wear shoes.


  11. I’m not sure where you are going, but much of your thesis so far was expounded vigorously by Carlos Castaneda in his books on Don Juan. Although his series began with writings about drugs, he went on to write about perception in a very eloquent way.

    Castaneda died quite awhile back, but science is just now beginning to catch up on this issue of perception, aided by modern technology and instrumentation.

    I look forward to reading what you have to say on this topic.


  12. Norwood Hanson (1969): “we usually see through spectacles made of our past experience, our knowledge, and tinted and mootyled by the logical forms of our special languages and notations… Unless there was a linguistic component to seeing, nothing that we saw, observed, witnessed, etc. would have the slightest relevance to our knowledge, scientific or otherwise… it might be that are language in the form of what we know puts an indelible stamp on what we see…”
    This is a restatement of the Whorf-Sapir Hypothesis according to which we perceive the world through the categories and limitations of our language. This matches with Wittgenstein’s case that the limits of our language are the limits of the world. (Shibles, 1974)

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