a cup of black coffee on a notebook with notes of foreign language with translation

Did you know that using, speaking in, and thinking in foreign and second languages can have real and significant affects on your thought processes and decision-making?

In other words, thinking in English can make you more objective, better at making financial decisions, and help you remember things in detail.

This is the Foreign Language Effect: let’s take the rest of this episode to discuss it in detail!

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  • Egotistical (adj): self-centred or selfish; believing oneself to be superior to others.
    • His egotistical behaviour made it difficult for others to work with him.
  • Rational (adj): Based on reason or logic rather than emotions.
    • In a crisis, it’s important to make rational decisions.
  • Thought process (n): The series of mental steps or cognitive activities that occur when one is thinking or reasoning.
    • Her thought process involved weighing the pros and cons of each option before making a choice.
  • Perceptions (n): The way in which something is understood or interpreted by the mind.
    • People’s perceptions of beauty can vary greatly from one culture to another.
  • Moral (adj): A principle or belief concerning what is right or wrong; ethical.
    • It’s important to make moral decisions even when faced with difficult choices.
  • Bias (n): a tendency to see things from one perspective.
    • The news article displayed a clear bias in favour of the political party it supported.
  • Risk (n): The possibility of loss, harm, or danger
    • Investing in stocks carries a higher level of risk than putting money in a savings account.
  • False memory (n phrase): An inaccurate recollection of an event or experience that did not actually occur.
    • Some psychological studies have shown that false memories can be created through suggestive questioning.

The Differences Between First and Second Languages

Have you noticed any differences between how you think in English compared to your native language?

You would not be alone.

It is well documented that the language we use can have a major and powerful effects on the way we think, remember, and make decisions.

From personal experience, I know that my personality changes significantly depending on which language I am using.

In English, I am quite reserved, struggle to make important decisions, and relatively serious. In Japanese, I am confident, brave, and less egotistical.

When speaking Japanese, I have agreed to things that I never would have thought about if I was speaking English. I once agreed to be Santa Claus at a Japanese kindergarten event; I entered multiple different speech contests; I agreed to teach English at my local bar in return for free coffee; I took multiple trips into the mountains with people I didn’t really know.

I would not have agreed to these things in English, but when speaking in Japanese my inhibitions, personality, and decision-making are different.

This is not just something I have noticed. In recent years, psychologists have become interested in researching, testing, and using the way our brains operate in different languages. They have discovered that by speaking a second language (for all of you, English), we can become more rational, improve our financial decision making, change our morals, and more!

This is the Foreign Language Effect. The idea that speaking in a foreign language can have real effects on our thought processes. In fact, thinking in English could have real benefits for many of you when it comes to decision-making!

With the rest of this episode, I want to introduce some of the different psychological theories about the way language shapes our brains and thought processes, and then discuss the Foreign Language Effect. We’ll take a look at some different studies and research projects that highlight various ways speaking in a second language affects us.

Hopefully this episode will serve as motivation for all of you to continue studying English. By the end of the episode, you should all see that speaking English as a foreign or second language can have powerful affects on your decision making and provide real benefits!

Linguistic Determinism

Before we get to the Foreign Language Effect, I think it is important to discuss an older, and more controversial, theory: linguistic determinism.

Linguistic determinism suggests that the language a person speaks can influence, and even determine, their thought processes, worldviews, and cognitive abilities.

In other words, the vocabulary and structure of the language you speak, shapes that way you see the world. It shapes and limits that way you understand what is around you. In this theory, we see the world through our vocabulary and language!

There are two different versions of this theory.

First, is linguistic relativity.

This is the weaker version of the theory.

It suggests that language can influence our thoughts and perceptions but does not completely determine them.

The main idea is that our languages might highlight or emphasize different parts of society or reality. English, for example, might push you to focus on different things compared to when using your native language.

A great example is the difference in languages when it comes to describing colours. Some languages have a much richer vocabulary for colours than others.

Most industrialised cultures have 11 main colours – black, white, red, green, yellow, blue, brown, orange, pink, purple and grey.

However, non-industrialised cultures tend to have much fewer colour words. According to an article in the Conversation, “the Papua-New Guinean language Berinmo has only five, and the Bolivian Amazonian language Tsimane’ has only three words that everyone knows, corresponding to black, white and red.”

So, if you speak the Bolivian-Amazonian language, and then switch to English, you will be able to describe the world much more vividly in terms of colours. Moreover, you may be able to see and understand the subtle differences between colours – like between orange and red, or green and blue.

The second theory here is a stronger version of the theory.

It suggests that language determines our thinking to a significant extent. According to this view, speakers of different languages not only see the world differently but are also constrained in their thinking by the linguistic categories and distinctions available in their language.

However, this concept is controversial and a subject of debate.

While there is evidence to support some degree of linguistic influence on our thoughts and perceptions, the idea of language entirely determining thought is not widely accepted.

What is the Foreign Language Effect?

This is where the Foreign Language Effect comes in!

Linguistic determinism suggests that the words and grammar of a language can change the way we see and experience the world. As I mentioned previously, languages with more colour words could mean speakers see more colours.  

The Foreign Language effect is different and more general. Rather than focusing on the specific features of languages, it considers the general experience of changing languages.

Take me for example. I speak Japanese. Linguistic determinism suggests that the vocabulary and grammar differences between Japanese and English will change the way I see the world when speaking and thinking in those language. The Foreign Language effect, however, suggests that it’s not the language features, but the different experiences.

I learned English naturally, through years of immersion with my family. I learned Japanese as an adult, through hundreds of hours of difficult study. Of course, things are going to be different in these two languages.

The Foreign Language Effect is when people make different decisions and think differently when they use a language that is not their native one. This happens because using a foreign language can change how we perceive risks and make choices.

It shows that language can affect our decision-making process, and it’s especially noticed in bilingual people who switch between their native language and a foreign one.

Ways learning a foreign language can improve your decision making!

What does the Foreign Language Effect actually do? What research has been done into the ways speaking in a different language can affect your thinking and decision-making? Let’s take a look at this right now – most of these examples come from an article I recently read (It’s linked here)!

Moral Judgements

One experiment into the Foreign Language Effect was conducted by Professor Keysar from the University of Chicago.

He was interested in how language may affect moral judgement. In other words, he thought that people might make different moral decisions in their first language compared to their second language.

He tested this idea with the famous “trolley experiment”. I’m sure many of you have heard of the trolley problem before, but if not, here is a simple explanation:

A train is coming down the tracks, but you see a group of five people stuck in the way. Next to you is a lever that can switch the train onto other tracks. However, there is 1 person stuck on those tracks. So if you do nothing, 5 people will die. If you pull the lever, you save those 5 people, but 1 other person will die. What do you do?

Keysar selected a group of native English speakers who had learned Spanish as a second language and posed them this problem. What did he discover?

People were almost twice as likely to pull the lever and change the tracks when they answered in Spanish (their second language) compared to English (their native language). Many people feel that pulling the levers is actively killing a person (even though you are saving 5 people) – but when thinking in a foreign language, they act in a more utilitarian way (meaning the way that benefits the most people).


Another study led by Professor Keysar looked at “myopic loss aversion”.

This sounds really confusing, but it is quite a simple idea. Imagine I give you an offer: I will give you $5, or we can flip a coin for $20.

Experiments have shown that people are more likely to take the guaranteed $5 than the possibility of $20. The evidence is that people don’t like risking small amounts of money, even if the chances of earning a high amount are good.

If we were to do the experiment once, many people would choose the $5. And if we were to do this experiment 100 hundred times… studies show people will still be conservative and choose the guaranteed money.

However, the logical thing is to take the risk – if the experiment runs 100 times, the mathematics suggests you should expect to receive twice as much by taking the risk over the long term.

This tendency against risk is a big problem in the world of financial investments – people dislike losing, and in the world of finance this could cost investors millions of dollars over years.

What does the Foreign Language Effect have to do with this? Well, Professor Keysar discovered that “myopic loss aversion”, the unwillingness to lose a little money for the chance of more money, happens less when people place bets or invest in their foreign language.

This might actually be a good tip for those of you listening who work in finance or investments. You may want to try thinking about your choices in English – you may be less emotional and more rational!

There are other studies into famous biases too!

One study in the Journal of Cognitive Psychology suggested that using a foreign language can reduce the sunk cost effect. This is one of the most famous problems in decision making – people are more likely to continue something (like an investment or project) the more money, time, or effort they have put in… even if it is the wrong decision!

Again, another reason why you all should think in English when making important decisions.

I also read a fascinating study in the International Journal of Bilingualism. They found that people are less egotistical (in technical terms, less susceptible to the bias blind spot) when using their foreign language.

Let me ask you a question – out of all Thinking in English listeners, where do you think you rank in overall intelligence? Most people overestimate their intelligence levels. Most people believe that others are stupid, and they are clever. But, in all groups, 50% of people are below average intelligence for that group.

The study found that this effect (the idea we think we are better than we really are) is less common in foreign languages. I know this from experience. I am much humbler in Japanese – I am acutely aware that I am not a fluent speaker and less egotistic.


As well as looking at cognitive biases and decision making, studies into the Foreign Language Effect have also revealed some interesting insights into memory.

For example, people experience less emotional pain and distress when talking about childhood trauma in their foreign language than their first language. This may be because our memories are connected to the language we were using at the time – so when we try to explain or recall them in our foreign languages, they seem less real, vivid, or powerful.

Moreover, thinking in a foreign language (so thinking in English for all of you listening), reduces the number of false memories created. In one of Professor Keysar’s recent studies, he gave a list of connected words (like “rest”, “snooze”, “bed”): people answering in their native language were more likely to say “sleep” ( a false memory) than if they answered in their second language.

The suggestion is that people are more careful when thinking in a learned language – you have to try harder to understand and comprehend the information… meaning you are more likely to remember!

Final Thought

What does all of this mean for you, as an English learner?

Sometimes, it may be useful for you to switch languages. Research suggests that you may all be more flexible, objective, and logical when speaking in English.

As I mentioned earlier, you may want to consider thinking in English when it comes to financial decisions – like thinking about your personal investments. Why? Studies show that you are less at risk of myopic loss aversion and the sunk cost fallacy.

In other words, thinking about investments in English means you are less risk-averse when the odds are in your favour, and less likely to continue bad investments.

Thinking in English could have many benefits for you. Whenever there is a controversial topic in the news, try reading an English article about it – you may be a little more objective. When you are talking about sad or bad memories, using English may make the experience a little better.

For those of you needing some motivation to study, hopefully this episode has helped. And for those of you already at a good English level, the Foreign Language Effect offers some unexpected benefits!

What do you think?

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By Tom Wilkinson

Host and founder of Thinking in English, Tom is committed to providing quality and interesting content to all English learners. Previously a research student at a top Japanese university and with a background in English teaching, political research, and Asian languages, Tom is now working fulltime on bettering Thinking in English!

5 thoughts on “263. The Foreign Language Effect: How Thinking in English Can Improve Your Decision Making and Memories! (English Vocabulary Lesson)”
    1. Dear Tom
      this article shows, once more time, how much important is learn english and make better every skill, as reading, speaking and writing. You are a very intelligent person and a great motivator. Thanks a lot!
      Wiliam (Italy)

      1. I have felt it, when I speak in English I feel that my personality changed, but now I realize that this can happen to everyone

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