Blind Spots – An introduction

Hi everyone.

Today, we’ll start with a quick visual exercise.

First, we need to hold out our left arm, elbow straight, out in front of us. Making a fist and holding up our thumb.

Next, we’ll close our left eye and focus on the back of our left thumb with our right eye.

Then, keeping our right eye focused on the back of our thumb, we just need to take notice of the things in the background of our vision. (The computer, the wall, the Tv, the sky.)
It’ll all be a bit fuzzy, that’s okay.

What we are looking for is any gaps in our background vision. Any missing areas, weird shadows, black circles etc. I’ll give us a moment to do this, see what we notice, and come back.


Cool. So, did anyone notice any gaps while we were doing that exercise? Anything dark or missing?

No one? Great! 🙂

(P.s. if anyone did notice anything, that is unexpected. You should probably check with a real eye doctor)


Okay, we just have one more step to go.

We start the same way. Holding up our left hand, elbows straight, doing a thumbs up. We close our left eye and focus our right eye on the back of our left thumb.

This time though, we will also need to stretch our right arm out the same way. Also doing a thumbs up, with both thumbs right next to each other, close enough to touch.

Now, we very slowly move our right hand away from our left hand (towards the right). Keeping our eye focused on our left thumb but paying attention to how our right thumbnail looks in the background of our vision.

Okay, if I’ve explained all this properly, something interesting will happen when our thumbs are about a foot apart. Our right thumbnail will disappear!

Even though we will still be able to see everything around it (including our hand and arm), we won’t be able to see our thumb itself! Then, as we slowly move it further away, it will reappear once again.

Try it and see! 😀


Cool, right? So what happened there?

Well, that’s our right eye’s blind spot. Due to the way the nerves in our eyes are arranged, there is a spot (just beside the centre of our vision) where we can’t see anything.

We can try moving our thumb up, down, and around in that area to get an idea how big our blind spot is. We can also test our left eye’s blind spot by following the same instructions, but swapping left eye for right eye and left hand for right hand.


That was nice.

So, apart from being an interesting little experiment, what is the big deal about blind spots? Why should we aspiring world changers worry about them?

After all, isn’t it just another area we can’t see? The same way we can’t see in the dark or see behind our heads. Well, that is not all it is.

Remember when we did the test with only one thumb? We were sure we weren’t missing anything. We believed that we could see everything in the background. It was only when we did a more detailed test that we realised that there was a significant gap in that area. A gap where we couldn’t see anything at all.

A blind spot is an area where we think we can see, even though we are totally blind. That makes a huge difference.

For instance, we know we can’t see behind our heads, so we turn around to look before walking backwards. We know we can’t see in the dark, so we stretch our hands out in front of us and walk slowly to feel for any obstacles.


If a driver knows they can’t see round a corner, then they will approach the corner slowly and carefully. Even if they got into an accident, it is likely to be a low speed accident, with minor damage.

However, if a driver believes they can see around the corner when they actually can’t,
(or if a driver doesn’t even see there is a corner but believes it is a straight road) then their behavior will be totally different.

In that case, if something goes wrong, the result is likely to be disastrous.


Okay, so far we have been talking about physical blind spots. These are easier to explain, test and verify.

We also have mental blind spots.  These are much harder to perceive, even though they can have much bigger impacts on our lives.

A mental blind spot is when we are sure that we know or understand something, without realising that there are huge aspects of that thing which we are totally blind to.

Like physical blind spots, we all have them. With physical blind spots, the things that are hidden by our blind spot depends on where we are standing and the direction we are looking. i.e., our perspective.

Similarly, the things hidden by our mental blind spots also depend on where we are mentally and how we view things, our mental perspective.

Our mental perspective is mostly formed by the environment we grew up in, and the lessons we learned about the way the world works.

The lessons themselves may be totally true but, because of our perspective, they may hide other equally valid and possibly important truths.

As a result of this, people who have grown up in a similar environment to us (and who have learnt similar lessons to ours) will usually end up with a similar set of blind spots.


Let’s look at a quick example, by answering these two questions about trees.

These are not trick questions. Yes, there are several types of strange trees out there that look weird. That’s not what we are asking about. We are asking about the “average” types of trees. The kinds we are likely to see growing by the side of the street, or in a park, or maybe in our garden. We can also exclude autumn and winter, because trees usually look very different then.

Okay, first question:

In general, excluding autumn, what colour are the leaves of most types of tree?

Yup, that’s right.
They’re green. Great answer!


Second question:

In general, excluding autumn, will one type of tree have leaves of the same colour as most other types of tree?

Ah, this one is interesting…


Over the past few months, I’ve asked this question to a few of my friends. Many of them answered the same way I would have.

“Well, yes. Of course.
If different types of tree have green leaves then their leaves are the same colour.
They’re green.”

A few of my friends answered differently though. After asking a few more questions, I found that they fell into two groups, gardeners and artists.

Those friends actually had the right answer. It turns out each type of tree does have its own, very specific, type of green.

These aren’t tiny, barely perceptible colour differences (like the difference between ‘beige’ and ‘eggshell’).

Some trees have leaves that are such a dark green that they look almost blue. Some are such a light green that they are practically yellow. Others may be a really deep reddish green, some have a greyish green tinge that almost looks like they are covered in dust, etc. , etc., etc.

Once we start to actually look at the trees, it seems so obvious. How come we never noticed it before?


This is what a mental blind spot looks like. Regularly looking at something, but never properly seeing it.

So let’s try to use this example to understand a bit more about mental blind spots and how they work.

How was this blind spot created in me? What let it last for so long? 

Well, I already know what colour leaves are. They are green.
Everyone knows this. We learnt it in primary school. Green is the correct colour for a leaf. Therefore, anything that is different from that is obviously an unusual exception.

Since I know this, whenever I did notice a leaf colour that wasn’t the “right” green, it was obviously “wrong“.

Perhaps the tree was sick, or the weather was too dry, or maybe it was just one of those weird exceptions that weren’t normal (there are always a few).

Once I had picked a “reason” for why a tree had leaves the “wrong” colour, I could safely ignore it.

This whole thought process would happen very quickly and totally automatically. So much so that I was barely conscious of it.

Without realising it, I was building up a mental filter whose job was to keep me blind to something I saw every day.


So what changed? How did I become aware of it?

Well first, some flatmates I had brought some plants into the house. So I had to help take care of them.

This meant I had to pay attention. Not just to what I did with the plants but also to how I thought about the plants and decisions I made about them. I was now paying attention to the plant-related thought processes that used to happen at the back of my mind.

However, that wasn’t enough. Because, when it came to the houseplants, my “reasons” worked. When the colour of the leaves started to become lighter or darker, it did mean something was wrong. My flatmates and I would try to figure out what it was and how to fix it.


A few weeks after this though, I was walking down a street one spring day, and I noticed a tree with leaves that were practically yellow.
“Hmmm, it must not be getting enough sunshine in that corner of the street” I thought.

The bush right next to it was much darker though.
“Hmm” I thought “perhaps the soil is different there”. 

But another tree next to the bush had a type of green different from those other two, but still not what I would consider “normal”.
“What could be wrong with that one?” I thought.

That was when I caught myself.

Because, even though I still hadn’t figured out what was going on yet, there is a rule that helps me catch myself when I make these types of mistakes.

The rule is

Once may be an exception,

Twice may be a coincidence,

Three times is a pattern!

I had just been making three excuses in a row about why what I was seeing really didn’t count. At that point I needed to stop, look around and re-evaluate.

Once I did that with an open mind, my mistake became clear. Looking around, there were at least 5 different types of green leaves on that street alone!

As I observed a bit longer, a pattern began to emerge. The same type of tree would have exactly the same colour of leaf. But every other type of tree or plant would have a different type of green. I continued to pay attention and test this idea as I walked around that day (after all that street may have been the exception). The new rule held consistently true.

Currently, I have only been able to test and prove this rule in the Uk. If you are reading this in another part of the world, I’d be curious to know the results of your own tests in the comments below.


We all have mental blind spots.

Blind spots have nothing to do with intelligence and very little to do with knowledge.

Blind spots are all about our perspective and our point of view (the point from which we are viewing the world). Something that is totally invisible from one point of view, can be blindingly obvious from another.

With physical blind spots, we can compensate for this by looking at things from a different perspective.

Our bodies compensate for one eye’s blind spot, not by having a better eye, but by having a second eye at a different position.

When a truck driver can’t see their blind spot, they may ask a passenger to check for them. Not because they believe the passenger has better vision, but simply because the passenger is sitting in a different position.

Even if the passenger can’t see as well as the driver, the simple fact that they have that different perspective means they can see things that the driver can’t. (A driver without a passenger might try to achieve a similar effect by leaning towards the passenger window and looking around from there).

Similarly, whether or not someone can help us with a mental blind spot is not based on how much smarter than us they are, but how different their point of view is from ours.

The more they disagree with us, the more likely they are to see something we don’t.



For Further Study:

Factfulness – Book – Hans Rosling

This is a beautiful book about how wrong we often are about the condition of the world. It discusses how understanding the true state of things can greatly improve our ability to make things better. The author also takes time to explore why we are much more likely to believe bad news rather than good news. He also discusses a number of tools we can use to get a better understanding of how things really are and what we can do to make them better.


This post from Humans of New York – Website – Brandon Stanton

In a single sentence, the photographer gives a great piece of advice to a young girl wondering how she can change the world.


Principles of success – Youtube Video (short series) – Ray Dalio

I’ve linked to this before. It is still one of the best summaries I have come across on the process of increasing personal power. In episode 6 and episode 7 it discusses the idea of blind spots and ways to approach them.


The Six Blind men and The Elephant – Another post on this blog – Me

This article talks about one of my favorite folk tales about blind spots. It makes us aware of a challenge which we each have to figure out how to address in our daily lives.


Hello, thanks for reading another post.

There are still a lot of tips and ideas to cover about identifying and dealing with blind spots. I spent many weeks trying to write a more complete guide on the topic before eventually realising that it was way too much material for a single post (or even a double one).
I’m currently a bit overdosed on the topic of blind spots though, so my next few posts will be about other things.
However, I will be revisiting various aspects of this topic in future.
Let me know if there are any specific questions about blind spots or their impacts that you’d like to know more about in the comments below

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