Does Anki Actually Work?
Anki utilizes a great deal of scientific evidence for memorizing information to help you remember more. But does it actually work?
In Short, Yes Anki will improve your memory. Anki uses evidence-based principles like spaced repetition and active recall which reduces the amount of forgetting that takes place after reviewing your Anki cards. However, Anki is not without its limitations and there are better alternatives in certain scenarios.
As we will see, there are better options out there than Anki when it comes to learning information (especially large amounts of information). These include techniques that apply information, draw connections between ideas, critique or argue for a position, and explain ideas in different ways. These are simply things that Anki does not do that we are missing out on by solely relying on it for studying.
What Anki Does Well
Anki is built on some pretty robust evidence-based memory principles. Ebbinghaus’s forgetting curve is a good way of visualizing how quickly we forget new information and where Anki comes in.1
If we look at the forgetting curve, you can see that as we learn new information our recall of it drops off significantly, even in the first 24 hours the dropoff is significant (see the red line in the image above). This is where Anki comes in. The Scientific principles Anki uses allow you to essentially “reset” the forgetting curve by reviewing the information again (these are the green lines).
But what are these principles that reset the forgetting curve? The two main principles Anki uses are Spaced repetition and active recall.
Active recall is having to pull something from memory yourself without a hint or cue. This is harder than just recognizing the correct answer and also more productive.2
There is evidence that actively retrieving information is much better for memory than passively restudying the material. One study found a 200% increase in retention for remembering names by using active recall!3
So how does Anki use active recall? Active recall is a natural consequence of the basic flashcard in Anki. You are shown a question and you have to recall the answer fully without any cues or hints.
There is even evidence that attempts at retrieval are beneficial even if they fail4. Meaning that you do not need to have a high success rate when it comes to your Anki cards. Failing them over and over is still beneficial for retention.
Second, Anki relies on spaced repetition2.
When learning something, putting a space in your schedule between when you first learned something and when you retrieve it again later has been shown to increase retention. Importantly, these spaces between retrieval sessions need to get larger and larger over time rather than being the same each time to get the most benefit2.
Another term for this is expanding retrieval practice. One study observed a significant benefit to using an expanding retrieval schedule compared to a uniform schedule. In General, when it comes to spacing out retrieval sessions, an expanding schedule is what works best5.
So how does Anki use spaced repetition?
Anki uses spaced repetition by giving you a prompt on how difficult each card was after completion and adjusting when you will see that card again. Anki does its spacing automatically this way for each card.
Taken together, Anki’s use of active recall and spaced repetition make it a powerhouse for remembering information. But this doesn’t mean that you should solely rely on Anki as a memorization tool. Anki has its limitations.
Firstly, just let me say that I am a big fan and user of Anki. I have been using it for years and have found it very useful in many circumstances.
But, Anki does have its limitations.
While Anki is amazing in certain scenarios, it should not be your main method of revision. This is simply because there are better ways to learn large amounts of new information out there. Anki is great at filling in the little details but it’s not good at giving you a big-picture view of a topic or helping you directly apply information.
Anki is a form of lower-level learning
This is best explained by appealing to a general framework of knowledge. Bloom’s Revised Taxonomy is a good way to explain Anki’s relative effectiveness to other studying techniques.
Bloom’s taxonomy has 6 layers (1 being “recall”, and 6 beings “create”). Generally, it is most beneficial to learn new information in the upper ranges up to the 5th tier (since creation is a bit different to learning)6.
Examples of learning at higher layers in blooms taxonomy are techniques like the Feynman Technique (level 2) or drawing mindmaps (level 4). These are generally going to be highly efficient ways of learning information that goes just beyond recalling facts and basic concepts.
You might be able to guess what I am about to say next.
Anki falls into the lowest level of learning according to Bloom’s Taxonomy. Anki is just about the basic recall of information. If you are practising a higher level of learning like drawing a mindmap at level 4 you are going to have a much better big-picture view of how the concepts in a given topic are related. Anki does not give you this big-picture view of why things are important or how they are related to each other.
What lower lower-level learning feels like
If you have ever studied a series of Anki cards and found that during the test you struggled to apply the information or answer a question like “How does x facilitate y compared to z?” then you have likely run into this. Anki does not prepare you for these types of questions.
I used to take weekly university quizzes and would use Anki to prepare for them. It would take me hours to make the cards and review them. I wasn’t doing badly, but I didn’t feel like I was as good as I could have done. Then I tried to use mind mapping (a higher-level technique).
My scores increased significantly. I actually started to get 100% on many of these in-class quizzes (they were not super complex so it’s not that impressive but it does demonstrate the point) and I spend less time preparing for them by using mindmaps.
When I first watched Youtubers talking about Anki I thought I had found the golden ticket to learning new information. But, my actual experience using Anki did not give me the expected results compared to trying out higher-level learning techniques like mind mapping.
Now, when I look at Bloom’s taxonomy, I understand why using higher-level learning techniques was so helpful for my grades. They just work better.
This is all because there is so much more to learning than just active recall and spaced repetition. These are only the tip of the iceberg when it comes to improving your learning and your grades.
Low time efficiency (when used on mass)
When you use Anki as your primary studying tool it’s not a time-efficient strategy.
The problem is Anki is that if you use it for a lot of material, the work just keeps piling on. You don’t learn something new and then move on to the next thing. Rather, you keep adding new material to study in addition to what you are already studying. Essentially, the speed that many students add cards is faster than you can review them. This makes the daily card load quite high, which can quickly become unsustainable.
Let me show you what I mean.
If you add 40 new cards per day (we are assuming here that you are using this to learn a lot of information) for a couple of months you will have roughly 2,400 cards to review over these months. On top of this, you will have to review all of them multiple times to remember them. While it is true that your cards will come back to you slower and slower over time due to spaced repetition, the rate at that you add cards is much higher than the rate they drop in their frequency.
However, it’s worth noting that this is not a problem if you rely on higher-level learning techniques for the bulk of what you need and then use Anki sparingly to fill in any gaps or details that are not covered. The problem is that most people don’t use Anki sparingly.
Limitations of Anki’s Different Card Types
So far I have covered what generally limits Anki. But there are more specific limitations to the different types of cards that you should also keep in mind when choosing whether to use Anki in a given scenario or not.
The three basic types of Anki cards are cloze, image occlusion and basic cards.
I wrote an entire article on why these card types are good for making Anki cards faster and my process for making them if you are interested in this aspect of Anki.
Limitations of Cloze Cards
The Anki cloze deletion card type allows you to hide parts of the text with a […] sign in your card that is revealed when you complete the card.
However, there are issues with cloze cards. When you view a cloze card you see the words around the […] sign and you guess the answer. Those words on each side act as a context that your brain uses as a memory cue. When you look at a cloze card the context surrounding the answer is reinstated and you will be more likely to get the answer right. This is called context-dependent memory.
There is research indicating that the context surrounding words you are trying to memorize acts as a memory cue. An experiment was conducted where participants had to memorize lists of words in the presence of other words acting cues (For example, Target: COLD, Cue: Ground). Subjects’ recall was significantly higher when they were presented with the cue than recalling the information alone7.
Similar effects have been found with other contextual features like the matching of background colours between studying and testing8.
This obviously raises issues for Anki’s cloze cards because the surrounding words are not occluded with the […] sign and these could be acting as memory cues. When you are taking a test you don’t have access to these memory cues and this means your test recall could be worse than your studying recall.
Limitations of Image occlusion Cards
The Anki Image occlusion card type allows you to hide parts of images that get revealed as the answer.
Don’t get me wrong. I love image occlusion cards and they are extremely handy. But these cards also have their limitations, though they are different limitations from the cloze cards. It essentially just boils down to there being better options.
The main issue here is that drawing images yourself is just a far better option than viewing them for recall. There are numerous experiments demonstrating that drawing images yourself is a significantly better technique for remembering information. There is an entire review on this that is worth checking out9.
Something better than an image occlusion card
If you want something better than an image occlusion card, the research indicates that you should probably just start drawing by hand9. For this, you can use a tablet with a stylus or paper and a pen/pencil.
There is also an Anki add-on that allows you to draw on the program. This means you can have a diagram as the answer but you have to draw it first. This is likely much more effective than an image occlusion card. The add-on is called Touch Screen and can be installed using code 1631622775.
Anki is fantastic for memorizing details or smaller pieces of information that help fill in your knowledge gaps before your exam. But Anki is also limited. If you want to make the most out of this useful tool then you should include other higher-level learning techniques. Some examples of these include mind mapping and the Feynman technique. These higher-level techniques result in much higher learning efficiency.
Because of the potential gains from other more effective learning strategies, it’s important to not solely rely on cloze cards or image occlusion. You should make sure to use Anki primarily as a memorization aid to supplement your main learning strategy rather than it being your main strategy.
- Murre, J. M. ., & s, J. (2015). Replication and analysis of Ebbinghaus’ forgetting curve. PloS One, 10(7), e0120644–e0120644. https://doi.org/10.1371/journal.pone.0120644
- Augustin M. How to learn effectively in medical school: test yourself, learn actively, and repeat in intervals. Yale J Biol Med. 2014 Jun 6;87(2):207-12. PMID: 24910566; PMCID: PMC4031794.
- Morris, P.E., Fritz, C.O., Jackson, L., Nichol, E. and Roberts, E. (2005), Strategies for learning proper names: expanding retrieval practice, meaning and imagery. Appl. Cognit. Psychol., 19: 779-798. https://doi.org/10.1002/acp.1115
- Kornell, N., Hays, M. J., & Bjork, R. A. (2009). Unsuccessful Retrieval Attempts Enhance Subsequent Learning. Journal of Experimental Psychology. Learning, Memory, and Cognition, 35(4), 989–998. https://doi.org/10.1037/a0015729
- Dobson, J. L. (2012). Effect of uniform versus expanding retrieval practice on the recall of physiology information. Advances in Physiology Education, 36(1), 6–12. https://doi.org/10.1152/advan.00090.2011
- Armstrong, P. (2010). Bloom’s Taxonomy. Vanderbilt University Center for Teaching. Retrieved [todaysdate] from https://cft.vanderbilt.edu/guides-sub-pages/blooms-taxonomy/.
- Tulving, E., & Thomson, D. M. (1973). Encoding specificity and retrieval processes in episodic memory. Psychological Review, 80(5), 352–373. https://doi.org/10.1037/h0020071
- Sakai, T., Isarida, T. K., & Isarida, T. (2010). Context-dependent effects of background colour in free recall with spatially grouped words. Memory (Hove), 18(7), 743–753. https://doi.org/10.1080/09658211.2010.508748
- Fernandes, M. A., Wammes, J. D., & Meade, M. E. (2018). The Surprisingly Powerful Influence of Drawing on Memory. Current Directions in Psychological Science : a Journal of the American Psychological Society, 27(5), 302–308. https://doi.org/10.1177/0963721418755385
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