Get ready to have your mind blown.

I was seriously shocked at some of these mistakes in thinking that I subconsciously make all the time. Obviously, none of them are huge, life-threatening mistakes, but they are really surprising and avoiding them could help us to make more rational, sensible decisions.

Especially as we strive for continued self-improvement as we build Buffer’s social media management platform, if we look at our values, being aware of the mistakes we naturally have in our thinking can make a big difference in avoiding them. Unfortunately, most of these occur subconsciously, so it will also take time and effort to avoid them—if you even want to.

Regardless, I think it’s fascinating to learn more about how we think and make decisions every day, so let’s take a look at some of these thinking habits we didn’t know we had.

1. We surround ourselves with information that matches our beliefs

We tend to like people who think like us. If we agree with someone’s beliefs, we’re more likely to be friends with them. While this makes sense, it means that we subconsciously begin to ignore or dismiss anything that threatens our world views, since we surround ourselves with people and information that confirm what we already think.

mistakes in how we think - confirmation bias, thinking mistakes

This is called confirmation bias. If you’ve ever heard of the frequency illusion, this is very similar. The frequency illusion occurs when you buy a new car, and suddenly you see the same car everywhere. Or when a pregnant woman suddenly notices other pregnant women all over the place. It’s a passive experience, where our brains seek out information that’s related to us, but we believe there’s been an actual increase in the frequency of those occurrences.

It’s similar to how improving our body language can actually also change who we are as people.

Confirmation bias is a more active form of the same experience. It happens when we proactively seek out information that confirms our existing beliefs.

mistakes in how we think, confirmation bias, thinking mistakes

Not only do we do this with the information we take in, but we approach our memories this way, as well. In an experiment in 1979 at the University of Minnesota, participants read a story about a women called Jane who acted extroverted in some situations and introverted in others. When the participants returned a few days later, they were divided into two groups. One group was asked if Jane would be suited to a job as a librarian, the other group were asked about her having a job as a real-estate agent. The librarian group remembered Jane as being introverted and later said that she would not be suited to a real-estate job. The real-estate group did the exact opposite: they remembered Jane as extroverted, said she would be suited to a real-estate job and when they were later asked if she would make a good librarian, they said no.

mistakes in how we think - confirmation bias 3

In 2009, a study at Ohio State showed that we will spend 36 percent more time reading an essay if it aligns with our opinions.

Whenever your opinions or beliefs are so intertwined with your self-image you couldn’t pull them away without damaging your core concepts of self, you avoid situations which may cause harm to those beliefs. – David McRaney

mistakes in how we think - confirmation bias 4

This trailer for David McRaney’s book, You are Now Less Dumb, explains this concept really well with a story about how people used to think geese grew on trees (seriously), and how challenging our beliefs on a regular basis is the only way to avoid getting caught up in the confirmation bias:

2. We believe in the “swimmer’s body” illusion

This has to be one of my favorite thinking mistakes I came across. In Rolf Dobelli’s book, The Art of Thinking Clearly, he explains how our ideas about talent and extensive training are well off-track:

Professional swimmers don’t have perfect bodies because they train extensively. Rather, they are good swimmers because of their physiques. How their bodies are designed is a factor for selection and not the result of their activities.

mistakes in how we think - swimmer's body illusion, thinking mistakes

The “swimmer’s body illusion” occurs when we confuse selection factors with results. Another good example is top performing universities: are they actually the best schools, or do they choose the best students, who do well regardless of the school’s influence? Our mind often plays tricks on us and that is one of the key ones to be aware of.

What really jumped out at me when researching this section was this particular line from Dobelli’s book:

Without this illusion, half of advertising campaigns would not work.

It makes perfect sense, when you think about it. If we believed that we were predisposed to be good at certain things (or not), we wouldn’t buy into ad campaigns that promised to improve our skills in areas where it’s unlikely we’ll ever excel.

This is similar to the skill of learning to say no, or how our creativity actually works: Both diverge strongly to what we think is true, versus what actions will actually help us get the result we want.

3. We worry about things we’ve already lost

No matter how much I pay attention to the sunk cost fallacy, I still naturally gravitate towards it.

The term sunk cost refers to any cost (not just monetary, but also time and effort) that has been paid already and cannot be recovered. So, a payment of time or money that’s gone forever, basically.

The reason we can’t ignore the cost, even though it’s already been paid, is that we wired to feel loss far more strongly than gain. Psychologist Daniel Kahneman explains this in his book, Thinking Fast and Slow:

Organisms that placed more urgency on avoiding threats than they did on maximizing opportunities were more likely to pass on their genes. So, over time, the prospect of losses has become a more powerful motivator on your behavior than the promise of gains.

The sunk cost fallacy plays on this tendency of ours to emphasize loss over gain. This research study is a great example of how it works:

Hal Arkes and Catehrine Blumer created an experiment in 1985 which demonstrated your tendency to go fuzzy when sunk costs come along. They asked subjects to assume they had spent $100 on a ticket for a ski trip in Michigan, but soon after found a better ski trip in Wisconsin for $50 and bought a ticket for this trip too. They then asked the people in the study to imagine they learned the two trips overlapped and the tickets couldn’t be refunded or resold. Which one do you think they chose, the $100 good vacation, or the $50 great one?

Over half of the people in the study went with the more expensive trip. It may not have promised to be as fun, but the loss seemed greater.

So, just like the other mistakes I’ve explained in this post, the sunk cost fallacy leads us to miss or ignore the logical facts presented to us, and instead make irrational decisions based on our emotions—without even realizing we’re doing so:

The fallacy prevents you from realizing the best choice is to do whatever promises the better experience in the future, not which negates the feeling of loss in the past.

Being such a subconscious reaction, it’s hard to avoid this one. Our best bet is to try to separate the current facts we have from anything that happened in the past. For instance, if you buy a movie ticket only to realize the movie is terrible, you could either:

a) stay and watch the movie, to “get your money’s worth” since you’ve already paid for the ticket (sunk cost fallacy)

b) leave the cinema and use that time to do something you’ll actually enjoy.

The thing to remember is this: you can’t get that investment back. It’s gone. Don’t let it cloud your judgement in whatever decision you’re making in this moment—let it remain in the past.

4. We incorrectly predict odds

Imagine you’re playing Heads or Tails with a friend. You flip a coin, over and over, each time guessing whether it will turn up heads or tails. You have a 50/50 chance of being right each time.

Now suppose you’ve flipped the coin five times already and it’s turned up heads every time. Surely, surely, the next one will be tails, right? The chances of it being tails must be higher now, right?

Well, no. The chances of tails turning up are 50/50. Every time. Even if you turned up heads the last twenty times. The odds don’t change.

mistakes in how we think - gambler's fallacy, thinking mistakes

The gambler’s fallacy is a glitch in our thinking—once again, we’re proven to be illogical creatures. The problem occurs when we place too much weight on past events and confuse our memory with how the world actually works, believing that they will have an effect on future outcomes (or, in the case of Heads or Tails, any weight, since past events make absolutely no difference to the odds).

mistakes in how we think - gambler's fallacy

Unfortunately, gambling addictions in particular are also affected by a similar mistake in thinking—the positive expectation bias. This is when we mistakenly think that eventually, our luck has to change for the better. Somehow, we find it impossible to accept bad results and give up—we often insist on keeping at it until we get positive results, regardless of what the odds of that happening actually are.

5. We rationalize purchases we don’t want

I’m as guilty of this as anyone. How many times have you gotten home after a shopping trip only to be less than satisfied with your purchase decisions and started rationalizing them to yourself? Maybe you didn’t really want it after all, or in hindsight you thought it was too expensive. Or maybe it didn’t do what you hoped, and was actually useless to you.

Regardless, we’re pretty good at convincing ourselves that those flashy, useless, badly thought-out purchases are necessary after all. This is known as post-purchase rationalization or Buyer’s Stockholm Syndrome.

The reason we’re so good at this comes back to psychology of language:

Social psychologists say it stems from the principle of commitment, our psychological desire to stay consistent and avoid a state of cognitive dissonance.

Cognitive dissonance is the discomfort we get when we’re trying to hold onto two competing ideas or theories. For instance, if we think of ourselves as being nice to strangers, but then we see someone fall over and don’t stop to help them, we would then have conflicting veiws about ourselves: we are nice to strangers, but we weren’t nice to the stranger who fell over. This creates so much discomfort that we have to change our thinking to match our actions—i.e. we start thinking of ourselves as someone who is not nice to strangers, since that’s what our actions proved.

So in the case of our impulse shopping trip, we would need to rationalize the purchases until we truly believe we needed to buy those things, so that our thoughts about ourselves line up with our actions (making the purchases).

The tricky thing in avoiding this mistake is that we generally act before we think (which can be one of the most important element that successful people have as traits!), leaving us to rationalize our actions afterwards.

Being aware of this mistake can help us avoid it by predicting it before taking action—for instance, as we’re considering a purchase, we often know that we will have to rationalize it to ourselves later. If we can recognize this, perhaps we can avoid it. It’s not an easy one to tackle, though!

6. We make decisions based on the anchoring effect

Dan Ariely is a behavioural economist who gave one of my favorite TED talks ever about the irrationality of the human brain when it comes to making decisions.

He illustrates this particular mistake in our thinking superbly, with multiple examples. The anchoring effect essentially works like this: rather than making a decision based on pure value for investment (time, money, etc.), we factor in comparative value—that is, how much value an option offers when compared to another option.

Let’s look at some examples from Dan, to illustrate this effect in practice:

One example is an experiment that Dan conducted using two kinds of chocolates for sale in a booth: Hershey’s Kisses and Lindt Truffles. The Kisses were one penny each, while the Truffles were fifteen cents each. Considering the quality differences between the two kinds of chocolates and the normal prices of both items, the Truffles were a great deal, and the majority of visitors to the booth chose the Truffles.

For the next stage of his experiment, Dan offered the same two choices, but lowered the prices by one cent each. So now the Kisses were free, and the Truffles cost fourteen cents each. Of course, the Truffles are even more of a bargain now, but since the Kisses were free, most people chose those instead.

Your loss aversion system is always vigilant, waiting on standby to keep you from giving up more than you can afford to spare, so you calculate the balance between cost and reward whenever possible. – You Are Not So Smart

Another example Dan offers in his TED talk is when consumers are given holiday options to choose between. When given a choice of a trip to Rome, all expenses paid, or a similar trip to Paris, the decision is quite hard. Each city comes with its own food, culture and travel experiences that the consumer must choose between.

When a third option is added, however, such as the same Rome trip, but without coffee included in the morning, things change. When the consumer sees that they have to pay 2,50 euros for coffee in the third trip option, not only does the original Rome trip suddenly seem superior out of these two, it also seems superior to the Paris trip. Even though they probably hadn’t even considered whether coffee was included or not before the third option was added.

Here’s an even better example from another of Dan’s experiments:

Dan found this real ad for subscriptions to The Economist, and used it to see how a seemingly useless choice (like Rome without coffee) affects our decisions.

mistakes in how we think - anchoring effect

To begin with, there were three choices: subscribe to The Economist web version for $59, the print version for $125, or subscribe to both the print and web versions for $125. It’s pretty clear what the useless option is here. When Dan gave this form to 100 MIT students and asked them which option they would choose, 84% chose the combo deal for $125. 16% chose the cheaper, web-only option, and nobody chose the print-only option for $125.

mistakes in how we think - anchoring effect 2

Next, Dan removed the ‘useless’ print-only option which nobody wanted and tried the experiment with another group of 100 MIT students. This time, the majority chose the cheaper, web-only version, and the minority chose the combo deal. So even though nobody wanted the bad-value $125 print-only option, it wasn’t actually useless—in fact, it actually informed the decisions people made between the two other options by making the combo deal seem more valuable in relation.

This mistake is called the anchoring effect, because we tend to focus on a particular value and compare it to our other options, seeing the difference between values rather than the value of each option itself.

Eliminating the ‘useless’ options ourselves as we make decisions can help us choose more wisely. On the other hand, Dan says that a big part of the problem comes from simply not knowing our own preferences very well, so perhaps that’s the area we should focus on more, instead.

Whilst we know that our decision making skills as people are often poor, (more on this topic here), it’s fascinating how “free” can affect us. In fact “free” has been mentioned before as one of the most powerful ways that can affect our decision making.

7. We believe our memories more than facts

Our memories are highly fallible and plastic. And yet, we tend to subconsciously favor them over objective facts. The availability heuristic is a good example of this. It works like this:

Suppose you read a page of text and then you’re asked whether the page includes more words that end in “ing” or more words with “n” as the second-last letter. Obviously, it would be impossible for there to be more “ing” words than words with “n” as their penultimate letter (it took me a while to get that—read over the sentence again, carefully, if you’re not sure why that is). However, words ending in “ing” are easier to recall than words like hand, end, or and, which have “n” as their second-last letter, so we would naturally answer that there are more “ing” words.

What’s happening here is that we are basing our answer of probability (i.e. whether it’s probable that there are more “ing” words on the page) on how available relevant examples are (i.e. how easily we can recall them). Our troubles in recalling words with “n” as the second last letter make us think those words don’t occur very often, and we subconsciously ignore the obvious facts in front of us.

Although the availability heuristic is a natural process in how we think, two Chicago scholars have explained how wrong it can be:

Yet reliable statistical evidence will outperform the availability heuristic every time.

The lesson here? Whenever possible, look at the facts. Examine the data. Don’t base a factual decision on your gut instinct without at least exploring the data objectively first. If we look at the psychology of language in general, we’ll find even more evidence that looking at facts first is necessary.

8. We pay more attention to stereotypes than we think

The funny thing about lots of these thinking mistakes especially related to memory is that they’re so ingrained, I had to think long and hard about why they’re mistakes at all! This one is a good example—it took me a while to understand how illogical this pattern of thinking is.

It’s another one that explains how easily we ignore actual facts:

The human mind is so wedded to stereotypes and so distracted by vivid descriptions that it will seize upon them, even when they defy logic, rather than upon truly relevant facts.

Here’s an example to illustrate the mistake, from researchers Daniel Kahneman and Amos Tversky:

In 1983 Kahneman and Tversky tested how illogical human thinking is by describing the following imaginary person:

Linda is thirty-one years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in antinuclear demonstrations.

The researchers asked people to read this description, and then asked them to answer this question:

Which alternative is more probable?

  1. Linda is a bank teller.
  2. Linda is a bank teller and is active in the feminist movement.

Here’s where it can get a bit tricky to understand (at least, it did for me!)—If answer #2 is true, #1 is also true. This means that #2 cannot be the answer to the question of probability.

Unfortunately, few of us realize this, because we’re so overcome by the more detailed description of #2. Plus, as the earlier quote pointed out, stereotypes are so deeply ingrained in our minds that subconsciously apply them to others.

Roughly 85% of people chose option #2 as the answer. A simple choice of words can change everything.

Again, we see here how irrational and illogical we can be, even when the facts are seemingly obvious.

I love this quote from researcher Daniel Kahneman on the differences between economics and psychology:

I was astonished. My economic colleagues worked in the building next door, but I had not appreciated the profound difference between our intellectual worlds. To a psychologist, it is self-evident that people are neither fully rational nor completely selfish, and that their tastes are anything but stable.

Clearly, it’s normal for us to be irrational and to think illogically, especially when language acts as a limitation to how we think, even though we rarely realize we’re doing it. Still, being aware of the pitfalls we often fall into when making decisions can help us to at least recognize them, if not avoid them.

Have you come across any other interesting mistakes we make in the way we think? Let us know in the comments.

Image credits: Evolving Personal Finance, Overload Online,, Relatively Interesting, Above the Market, Blue Dog’s Eyes, Swim. Bike. Run.,

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Written by Belle Beth Cooper

Belle is the first Content Crafter at Buffer and co-founder of Exist. She writes about social media, startups, lifehacking and science.

  • John

    Love it thanks!

  • Fascinating stuff! The more I learn about the brain, the more I realize it is not the smooth-running machine we’d like to think it is. It’s said that 95% of our decisions are made on an subconscious level. This post supports that we aren’t as much in control of our decisions as we’d like to believe.

    • borderedhessian

      [citation needed]

  • Jen McGahan

    Yowza. I just spent 10 minutes reading this, knowing logically that I should be writing. Couldn’t tear myself away, though. The subscription pricing example was amazing to me. Juicy stuff, Belle Beth. Thanks!

    • Belle

      Thanks, Jen! Glad you liked it 🙂 I really liked that subscription example, too.


    Awesome post! We talk about this a lot at our blog seeing as how we’re in the business of group decision-making. You absolutely nailed it on #’s 1, 4, 6, 7, and 8. These are the cognitive biases we find grant committees, startup incubator and accelerator review teams, and Universities/Colleges falling into all of the time!

    On a side note, if you haven’t seen it yet, check out this hilarious video on cognitive biases (not my video).

    • Belle

      Thanks for sharing that!

  • Susanne Krause

    Great read, thanks for sharing, love such topics. I’m currently reading Thinking Fast and Slow it’s an amazing book.


      It really is! You’ll start catching yourself recognizing little glitches in your thought process. Remember though, while we can become more aware of these tricks our brains play, we cannot undo the fact that we’re human and we will continue to make some of these errors, despite our best efforts. Technology can offer some help thankfully!

  • Raj

    Good Content, really loved the point about Economist Subscription Belle!

  • Roberta Kedzierski

    Very thought-provoking, Thanks.

    These areas fascinate me:
    1) people who assume that something they have just noticed is brand-new. Period. And not just brand-new to them.
    2) that there appears to be a time-warp in what I can only call the collective-unconscious. Such as the use of the “floppy-disk” symbol to represent the “save” function in computer programs. Also, for example, references to TV programs that no-one born after 1960 will have seen, let alone someone who came along 50 years later! This may be more of a problem in the UK than in the USA. (I am a Brit.) Some action is being taken: I know that a leading US university (forgot the name) publishes an annual list of anachronisms to help the professors in their dealings with the freshmen.

  • Engelsman Robins

    Waaaaaay back before it was common for women to hyphenate their maiden and married names, I did it as a tribute to the wonderful father I learned had adopted me. (I always thought I was also one of his “real” kids.) I applied for a job and the man who sat behind the big desk interviewing me looked at my resume, looked over it at me and muttered “Are you one of those man-hating feminists?” based on my hyphenated name. Could he have BEEN more wrong?

  • Excellent article and really makes you think about how difficult it is to change the way you think! Mind boggling! Thanks for taking your time to assemble this wonderful article and the various references.

  • Great post, and stellar research! Your articles are definitely on the longer side, but I always read the whole way through, without regrets. Good material!

    I also thought that last quote from Daniel Kahneman was fantastic, especially because one of my Bachelor degrees was in Economics. I think out of context it may not be as revolutionary, though. It’s important to note that in main-stream Economics, the basis of social/economic theory is that:

    1. All individuals taking part in an action/activity are behaving rationally, and
    2. All individuals act in their own self interest.


      I highly recommend reading Kahneman’s book “Thinking, Fast and Slow”. This post just touches the tip of the iceberg of all the funny tricks our brains play in the decision-making process.

      Belle, I feel like we’re reading the same material! 🙂

  • Brilliant article. There are so few brilliant articles on this topic being written today. This puts my article to shame. Regards, Slim “Eggheads and Cracked Eggs” The Empirical Method of Analysis.

  • rivengodwind

    Hmm, you may need to check your example on cognitive dissonance — there’s a certain amount of momentum needed to change one’s belief. In this case, in the example, the person you are depicting is just as probable to become *more helpful* to strangers because of what he did. At the very least, he’ll become more helpful to the next stranger he meets. Cognitive dissonance assumes directionality towards the original belief, unless there are other factors affecting it.

    Oh, and could you add references to your quoted paragraphs? A lot of us would probably want to read more about them.

    • Belle

      Thanks for jumping in here. Each quote should have a link in the preceding statement to show where I got it from. I’ll think about a way to make this more obvious in future posts.

  • Amazingly well written article. Thought provoking as well as useful. Great job done Belle! Highly appreciate!

    • Belle

      Hi Harmanjit, thanks for the comment! For now, these are definitely the best ones I know, alongside anything written by David McRaney or Vaughan Bell 🙂

  • James Knighton

    The ‘Swimmer’s Body’ illusion is a bit misleading. I understand the main point that we underestimate how natural ability affects results and that we are too optimistic about what we can achieve through hard work, but the quote you provided takes it to the other extreme.

    Michael Phelps’ body is optimised to be the perfect swimmer, which is why he wins gold medals, but that would all be wasted potential if he didn’t train for it. Perhaps Rolf Dobelli’s book goes into more detail and acknowledges this, but the quote provided makes it sound like the training is secondary to his natural ability.

    It promotes a growing belief in terms of fitness, the idea that someone is naturally fat and therefore shouldn’t try to lose weight, which is dangerous and unhelpful.

    • Belle

      Hi James,
      Good point there—thanks for chiming in. I think what Dobelli is getting at is more of the things that can’t be changed, like height and limb length. You’re right about general health and fitness—we wouldn’t want to make it sound like those come naturally at all.

      • disqus_bBy32DPGZ6

        I think using Phelps is a great example of conformation bias. I’m pretty sure you could find a successfull swimmer with less efficient proportions. And we have an incredible ability to change our central nervous system through training so natural predispositions probably don’t play a pivotal role in sports or when learning other activites.They can be an advantage of course but not without proper training. Neuroplasticity has a large body of scientific evidence to back it up. Your somatosensory, premotor, motor cortex and other areas develop more connections and expand with practice which is on its own by far more important than bodily proportions. Saying that, it’s great to have both on your side for an optimal effect.

  • Good and complete article, im learning so much, the mind not ever accurate

  • Halli

    Love the article, but cant help but to think that I am biast now, because these are things I was thinking about already!

  • May Chong

    Well researched and well written. Thanks for the article.

  • Diane Diane

    I absolutely loved this article. This stuff should be flushed out into a full semester required course in all high schools.

  • altryne

    Lovely post. Learned a lot. Especially the Dan Ariely stuff. Mindblowing

  • Привычка – вторая натура.

  • Andy Waltz

    This article inspires me a question: is it worthy to make the effort of searching for fallacies in our thoughts? I think we unconsciously associate ‘logic’ to ‘good’, as positivists did, but I believe that sometimes (for not-so-important decisions, that is) it could be better to go along with our irrationalities, as they may make life more enjoyable. Does anyone think the same?

  • Interesting. I was never aware that I was already doing the same mistakes above. Love the post. 🙂

  • Gustaf is a Coding Traveler

    I see myself as a quite smart person, but i “feel caught” in most of these thinking mistakes. Thanks for sharing, good stuff to keep in mind.

  • guest101

    i liked this blog post alot

  • Phil Barden

    Nice piece. I spent 25 years in marketing and then switched to ‘decision science’ consulting having had my mind blown by things like this. (self-promotion alert) You can see how they and Kahneman’s work relate to marketing and advertising in my recent book ‘Decoded. The Science Behind Why We Buy’

  • linda_alberts

    I fall into the sunk cost fallacy a lot. You’re right – you have to let it stay in the past and move on! Also, the anchor effect is what the movie theaters use to convince to upgrade to a large popcorn and soda for only .50 more! I think it’s important to mention that the brain is 60-80% fat so we need to feed our brains properly (eat healthy fats) to keep it working the best it can!

  • Stephen Turnock

    Interesting insights into thought process. I observe there are two types of people – internal and external referencers. Internal referencers are those whom base their decisions on their own internal knowledge and do not ever take into account any information and knowledge outside their bubble. Actually they may work on a hunch also ( the reassuring lie maybe).

    External referencers on the other hand make great decisions (and leaders) as they always take on board external knowledge and debate and reason. Some peoples radius is zero and they call this their opinion and tend to surround themselves with people that agree with their beliefs. Now some people reading this will think, well I’m OK then, I’m an external referencer, but in reality they are not as that is their gut feeling!

  • yes-brainer

    Methinks that these ‘irrational’ ‘mistakes’ are nothing of the sort. The human brain is a learning machine, designed for spotting patterns and constantly refining its processes of operation. Our biases are not encoded in our genes, but are learned through trial and error in everyday experience as successful strategies for everyday life.

    For bigger decisions we can afford to spend time thinking things through and making a rational choice – and that is something our brains are perfectly capable of! Thousands of years ago, there were successful armies that made decisions based on logic, not emotion. Of course the logical mind needs more training, including learning about some of our biases, but those biases deserve a lot of credit for getting us through millions of tiny decisions each day.

    • turi


      • John

        Your first sentence reminded me of General Zod.
        “This… Superman is nothing of the sort…”

  • jonnyblamey

    Many of these points are seriously dubious. They are based on a highly individualist model of human nature and also are biased towards a certain view of statistics that can’t be defended against even mild criticism. Take for example n as the second to last letter versus words ending in ing. Of course one interpretation of this question makes it logically necessary that there are at least as many words with the second to last letter being “n” because words ending in ing are a subset of words ending in n. But for this very reason, we don’t interpret the question in this way. Logicians and probability theorists take OR to be compatible with AND, but in natural language OR is often taken to indicate a mutually exclusive set of alternatives. So the question does “bring” have n as the second to last letter or does it end in “ing” yeilds the answer “it ends in “ing” because the oppositional mode of the question makes words ending in n blank not include words ending in ing. This interpretation is obviously the right one in any context except for where a scientist is trying to make you look stupid. The bank teller feminist question is also analysable in this way.
    On to confirmation bias, lets see if you reject this comment in favour of the beliefs you already hold. : )

    • Duh

      It’s funny because you used confirmation bias to reject his article.

  • Tom Kelsall

    I have to take issue with #4. Yes, the odds of “Tails” coming up on any individual throw are 50/50. HOWEVER – the odds of throwing 5 “Heads” in a row are a LOT LESS than the odds of throwing 2 “Heads” in a row… and the more times you throw, the longer the odds of the same one coming up again.

    If you toss the coin 400 times, you’re extremely likely to get very close to 200 tails and 200 heads – but getting 200 tails FIRST and then 200 heads? Almost astronomically unlikely.

    • LadyNepsy

      This last part is a good point, but the statement “the more times you throw, the longer the odds of the same one coming up again” is incorrect. In this scenario, they are only trying to predict the next coin flip. In that case, it doesn’t matter that the last 4 were all ‘tails.’ The likelihood of the next coin flip being ‘tails’ is still 50/50 (assuming a perfectly weighted coin, of course). If you were trying to predict 5 coin flips all landing ‘tails’, then the probability would be (.5 x .5 x .5 x. 5 x .5= .03125), so roughly a 3% chance of 5 consecutive throws landing ‘tails’, which is much smaller than the odds on a single throw.

      However, knowledge of the first four outcomes still does not impact the odds of the next throw; they are still 50/50. The only reason that equation above even works for calculating the joint probability of 5 ‘tails’ in a row is because the odds of each throw is independent. Thus, the odds of getting ‘tails’ on any given throw is in no way dependent on the previous coin toss outcomes. Probability is based on an infinite number of throws, so it is possible to get 400 tails in a row even through the odds are still 50/50 each time (highly unlikely, sure, but possible). As humans we are pretty bad at dealing with this idea, which is why people tend to think that if the last 4 throws were ‘tails’ then the next one is bound to be ‘heads’ because a series of 5 ‘tails’ in a row is so rare. Each throw is completely independent. The previous outcomes only matter if trying to predict a series.

      • Paul Smith

        Bit of a necro here, but you’re only correct if you’re absolutely certain the coin is fair.

        If you don’t know anything about the nature of a coin, having it flip 400 tails in a row is at least evidence that the coin may not be fair. Of course, this results in the opposite prediction – if I had seen a coin flip tails 400 times in a row, I would bet it will flip tails again, not suddenly revert to heads.

        • jerry

          If the person is practiced at coin tossing and they know how much force to apply to the coin in the toss they can make it show up tail or heads by placeing the coin in the position of which side they want to control in the up position before the flip of the coin. nonbelievers get to practicing : )

  • Philip Loh

    Thanks, but you just confirmed what I already knew. 😉

  • Jeremy Giam

    I disagree with the Sunk Cost Fallacy study: Most people choose the more expensive albiet “less enjoyable” holiday because they can pay $50 next time to go for the cheaper but “more enjoyable” holiday.

    If they choose the cheaper but “more enjoyable” holiday. They have to spend $100 in future to experience what they have chose to miss out.

    This is not sunk cost fallacy. This is looking ahead and calculating future costs. Ultimately they will spend $50 more to experience both holidays if they chose to give up the “expensive” option and most people will assume costs stays the same in future.

    • Your example simply reinforces the sunk cost fallacy: “If they choose the cheaper but “more enjoyable” holiday, they have to spend $100 in future to experience what they have chose to miss out.”

      Why would anyone spend more money in the future to experience a worse outcome except in some attempt to recoup the “sunk cost” he/she invested initially?

      • Kev

        Maybe I’m missing something here, but I think you are agreeing with Jeremy.

  • mundacho

    I really enjoyed this post. It was entertaining and enlightening :-).

  • Talton

    At least it’s possible to train yourself to notice these cognitive mistakes, though it usually involves making them in the first place.

    I think #3 affects most people when presented with learning something new. Especially when you’re not forced to, it can be difficult for most to see the benefits beyond the tipping point of learning and knowing.

    #6 became very apparent to me after moving from Texas to SF. In Texas, it’s all about the buffet, massive portions, and cheap calories, while not considering the value of what you’re actually eating. I remember trying to explain to a restaurant that I didn’t want/need unlimited sides. There was a total disconnect.

    It’s crazy and often leads to hoarding. I find it interesting the way that this cognitive behavior has shifted to digital storage in the present day. Now when purchasing, I’m quicker to consider the “cost of ownership” (storage, upkeep, etc.), which helps me prevent most unnecessary purchases.

  • I just did a poster series (info graphic-ish) on 9 logical fallacies. It is true that many if not most of the things we believe or assert have faulty logic. If schools were to teach critical thinking they couldn’t operate like factories designed to help people conform and comply. Nothing is more scary to the powerful than people thinking for themselves! 🙂 here’s the first poster of 3 (so far)

  • Mike Tang

    Thanks Belle, this is great!! I shall use and check on myself every now and then. It helped immediately on my work related matters. I am bless! Happy Holiday!!

  • SteveMO25

    Agree with most except No. 2 “Swimmer Body”… Sounds like lame excuse for fat people if you ask me. I’m very average athletically and have a very carved hard body. I’m very proud of it. And I sure as hell wasn’t born with it… I have to work my butt of to maintain it. Anyone who is young and not obese can achieve a great physique if they put in the work.

    It’s simply requires intense effort and dedication. But our culture can be so lazy and piggish that some just assume “If I wasn’t born with a naturally ripped body than I’ll never have one.” Nonsense. Just giving people an excuse.

    The rest were good though. Great read.

    • sKiacz

      So…you have a swimming contest against someone exactly like you and all things being equal with one exception….his/her arms are 4″ longer and his/her body naturally produces less lactate than yours. He/she will win, and this is based on two things you are born with, so no matter how “carved” your body is, someone else is naturally superior to you.

  • turi


  • BF

    RHET 1010 brought me here.. Anyone else?

  • Samer Helmy

    Loved the article. Spot on, we even apply a few marketing techniques in our business that exploit one or two of the mistakes mentioned. (Muahahaaa… don’t hate us though! )

    However, i think points 7 and 8 needed better examples. The two used did not purely demonstrate a thinking mistake, but could very well be linguistic comprehension mistakes.

    For 7, When presented with either words ending with -ing vs words with the letter -n- being the penultimate letter, the assumption could be that -ing is implicitly excluded in the second.

    For 8,the second option provided implied that in the first option the statement meant Linda is purely a bank teller that is not involved in the feminist activism.

    The two examples can therefore be of assumption mistakes leading to bad comprehension. They do not purely demonstrate the memory heuristic reliance mistake and stereotypical thinking mistake suggested.

  • and hay

    bit odd with the assertion that scientists are exempt from being limited by preconceived and closed thinking… as
    if… yes some will push the boundaries of what we know but areas or research, methodology and interpretation of finds surely has to be affected by prejudice to some degree. the scientist or person who can really accept things that challenge or undermine their belief system surely is very rare in deed and are all discoveries made by scientists anyway or can the rest of us observe things that challenge accepted thinking?

  • Dean

    Thanks, nice piece about human bias and inference.

  • bri44any

    Also, words ending in “ing” have “n” as their second to last letter, so the “ing” count is automatically added to the “n” count, resulting in an automatic tie but more likely a win for the “n” count.

  • Hans Johan Svensson

    We try to keep facts in our memory. We do´nt allways succeed. And (again) there was a tinme when the knowlegde of mankind would fit into one brain. That was the older stoneage some 50 000 years ago – so, now we have to trust the good will of others to fill us in. And, some are dishonest – but, as we only can carry what is in our own brain (until we learn something new) we will not, a lot of the time, be able to tell if we are fooled or not.
    Wich is why we need democracy to write laws (amongst other things). These laws are hopefully a representative of all of our knowledge so far – they are also a public record (in a democracy) and in constant scruteny. We can allways vote and rewrite.

  • Mark Roth

    “Especially as we thrive for continues self-improvement”

    What does that mean?

    Maybe *thrive* is supposed to be *strive*?

    And *continues*, *continuous*?

    I’ve read and read that…

    • Hmm, great catch, Mark! My guess is that it might be “Especially as we strive for continued self improvement…” Big thanks for noting that one; I’ll fix it up now!


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