Alex Chiri's Blog

Desirable difficulties - long-term learning on steroids

We are in a period of immense abundance of information, and yet, I think we are not taught how to learn in a proper way. The lecture-and-memorization-until-test is a poor-mans strategy at best. I also found out that most people I talked to don't really have a strategy for learning.

The most common answers I got to the question "How do you learn something new?" were "I read a book", "I follow a course online" or "I watch YouTube". All of those answers are valid, but none of them represent a learning strategy. They represent sources of information and not how people actually learn from the content provided by the source of information, how we integrate new information and how we develop new skills, ideally for the long term and not just for passing a test.

There are some techniques we can use to make learning more effective in a deliberate way. They are not obvious and usually counter-intuitive. They are collectively called "desirable difficulties".

What are desirable difficulties?

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Obstacles that make learning more challenging, slower, and more frustrating in the short term, but better in the long term. - David Epstein, Range

Or better yet, watch the short video below where Dr. Robert Bjork (one of the cognitive psychologists that coined the term) explains himself what desirable difficulties are and gives some examples:

Even ineffective learning can be hard and maybe not so pleasant, so I get it why when people hear that effective learning involves challenges and some frustration they are not quite jumping around with joy. All these techniques have been proven to work in many experiments and although they are not without challenges, you know they are worth it! 😊

  1. The generation effect

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One of the techniques that I apply many times is called the "generation effect". It is a very simple concept: whenever you struggle to find an answer to a problem on your own it will yield better, deeper, longer lasting learning. Even if the answer you found is wrong. So whenever someone is giving you a tip or directly the solution to a problem, they are helping you on the short-term, but they are also preventing you from learning more on the topic of the problem.

In software development, it is rather common to find tips or solutions on Google or StackOverflow, which is jokingly called copy/paste programming. And it is completely fine for some tasks, but when approaching things this way, we are missing out on understanding the details about the solution. The details are very useful when we are interested in learning more about the technology or the area of the problem. The search for a solution might expose us to completely random things related to the problem. All of these help us deepen our understanding about the topic, learn more concepts that we might be able to apply in other problems we will encounter in the future.

It’s much harder to find answers on our own, but it is very beneficial for our learning. That doesn’t mean we shouldn’t benefit from the experience and knowledge of others, just that we should be mindful when it’s actually better for us to figure out things ourselves and when it doesn’t matter that much.

Being forced to generate answers improves subsequent learning even if the generated answer is wrong. It can even help to be wildly wrong. Metcalfe and colleagues have repeatedly demonstrated a "hypercorrection effect." The more confident a learner is of their wrong answer, the better the information sticks when they subsequently learn the right answer. Tolerating big mistakes can create the best learning opportunities. - David Epstein, Range

  1. Spacing

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It is what it sounds like-leaving time between practice sessions for the same material. You might call it deliberate not-practicing between bouts of deliberate practice. - David Epstein, Range

Instead of trying to jam everything into our brains at once, we should plan our learning in spaced-out sessions. Maybe a day or several days apart, depending on our schedule and goals.

Study-phase retrieval is based on the premise that retrieval benefits learning, and spaced learning opportunities are more likely than massed learning opportunities to involve retrieval of the previous learning experience. - Shana K. Carpenter, Distributed Practice or Spacing Effect

In every study session, it is beneficial to repeat some of the concepts studied in previous study sessions, which represents the core idea of another desirable difficulty that I mention below, retrieval practice. And, actually, if we forget some of the things we learned in a previous session and we revisit them in a subsequent session, this actually increases the strength of learning those ideas or concepts.

The important thing about spaced practice is that its effectiveness depends on the delay between the study session(s) and the final test or exam. - Yana Weinstein, Megan Sumeracki, Oliver Caviglioli, Understanding How We Learn

If there is a test, then it should not be immediately after a session of study, ideally a day or two away.

More recent evidence suggests that spacing learning opportunities across different days may benefit memory due to sleep-dependent neural consolidation processes. - Shana K. Carpenter, Distributed Practice or Spacing Effect

Night sleep helps consolidate new things we learn during the day and when we study across several days, we give sleep the opportunity to work its magic on our memory.

Spacing may be effective in part because it increases what some researchers call “storage strength” – a measure of deep learning – rather than our current ability to produce information. - Yana Weinstein, Megan Sumeracki, Oliver Caviglioli, Understanding How We Learn

  1. Interleaving

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Now, we could simply watch some movies or enjoy time-off with our family and friends between the learning sessions on a specific topic, or we could take the time to learn some more, but on a different topic.

In a study using college math problems, students who learned in blocks-all examples of a particular type of problem at once-performed a lot worse come test time than students who studied the exact same problems but all mixed up. The blocked-practice students learned procedures for each type of problem through repetition. The mixed-practice students learned how to differentiate types of problems. - David Epstein, Range

And when we mix topics, especially complementary topics, we might start seeing patterns that can be applied to those topics.

Interleaving has been shown to improve inductive reasoning. When presented with different examples mixed together, students learn to create abstract generalizations that allow them to apply what they learned to material they have never encountered before. - David Epstein, Range

  1. Retrieval practice or testing

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Retrieval practice involves reconstructing something you’ve learned in the past from memory, and thinking about it right now. In other words, a while after learning something by reading or hearing about it, if you bring the information to mind then you are practicing retrieval. - Yana Weinstein, Megan Sumeracki, Oliver Caviglioli, Understanding How We Learn

Testing is probably one of the most used desirable difficulty when studying for an exam, but there are some interesting details about it that maybe are not so well known.

For example, when we test ourselves on some things we learned in the past and we try to bring those ideas back from memory, we are actually changing that memory, so they don't usually come out exactly as we have learned them in the beginning. But, at the same time, this process has been proven to make the memory more durable and more flexible.

Retrieval practice, like spaced practice, tends to produce learning benefits after a delay. If the assessment test is happening immediately, then students tend to perform best on the test after they have repeatedly read the information compared to when they have practiced retrieval. - Yana Weinstein, Megan Sumeracki, Oliver Caviglioli, Understanding How We Learn

After how much time should the test be to benefit the most from retrieval practice is not clear in research. What is clear is that when the test is immediately after studying, students who used retrieval practice performed worse than the ones that just tried to assimilate as much information as possible in the time they had.

Conclusions

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Desirable difficulties like making connections and interleaving make knowledge flexible, useful for problems that never appeared in training. - David Epstein, Range

Desirable difficulties like testing and spacing make knowledge stick and becomes durable. - David Epstein, Range

Desirable difficulties are no silver bullets, but they are proven to help long-term retention of the things we want to learn. Whenever you find yourself learning something completely new, I suggest you give them a try.

Bonus: a short recording of me presenting some of these desirable difficulties with some quotes from the book Range, by David Epstein.