Monthly Archives: February 2023

Demos for Teachers #5: Schema theory and memory


I learned about schema theory and memory from S. Chew’s article “Having Knowledge Is Not the Same as Using It” (thanks Steve! Download available here from Researchgate) and I keep thinking about applications for teaching and learning. It’s my new favorite thing!

As Steve describes in the article, schema (mental rules we use to organize the world) influence how we encode (or don’t encode) new information about the world. After I read Steve’s article, I got curious about how I missed learning about schema theory, and I think I figured it out: for some reason, schema theory is not referenced in the context of memory in the AP Psychology curriculum (that’s my primary teaching context), but it is in the IB curriculum. This seems like an oversight! Schema theory is MUCH more useful and important than many of the details AP Psychology teachers have to teach (e.g. the difference between retroactive and proactive interference – ugh!)

In his article, Steve describes research from Bransford and Johnson (1972) that involves reading a paragraph aloud to participants and testing their memory of the information from the paragraph. Their study was designed to measure the impact of listeners having or not having a useful schema for the paragraph before they get to hear it. If you didn’t jump ahead to to the article already, you can try this for yourself: read the paragraph below and think about how confident you might be if someone gave you a pop quiz about this information:

“The procedure is actually quite simple. First you arrange items into different groups. Of course,
one pile may be sufficient depending on how much there is to do. If you have to go somewhere
else due to lack of facilities that is the next step, otherwise, you are pretty well set. It is important not to overdo things. That is, it is better to do too few things at once than too many. In the short run this may not seem important, but complications can easily arise. A mistake can be expensive as well. At first, the whole procedure will seem complicated. Soon, however, it will become just another facet of life. It is difficult to foresee any end to the necessity for this task in the immediate future, but then, one never can tell. After the procedure is completed one arranges the materials into different groups again. Then they can be put into their appropriate places. Eventually they will be used once more and the whole cycle will then have to be repeated. However, this is part of life”. (Bransford & Johnson, 1972, p. 722)

The feeling of confusion or lack of confidence you may be feeling right now may be similar to how many of Bransford and Johnson’s participants felt. Some of the participants heard that paragraph without any previous information. But others got this crucial piece of information – a schema – before hearing the paragraph: “This paragraph is about washing clothes.” Knowing that schema before hearing the paragraph impacted what they learned:

Chew, S. (2022) Having Knowledge Is Not the Same as Using It, The Teaching Professor, Dec. 12, 2022

Steve does a great job in the article discussing aspects of this study that are important for teachers: participants who knew the topic of the paragraph before hearing it did better on both the comprehension and the recall measure in the study. But participants who got that information after they heard the paragraph did no better than participants who never learned the topic! There are schema students need BEFORE they go through a learning experience in order for that experience to be useful. If students don’t have the right schema, the learning experience might be a waste of time.

I talked about this experiment with science teachers recently and it started a great conversation. I first handed out a slip of paper to each teacher (pg. 2 of this handout). The teachers didn’t realize that half of them got the version of the instruction with the schema and the other half got the version without (I dealt off the top of the pile to half the room and off the bottom to the other half). Then I read the paragraph (pg. 1 of this handout) and was going to tell them whether they were group A or group B and ask that they fill out this google form (we didn’t go through with the data collection b/c it would have been tricky to ask everyone to use devices at that moment in time).

The science teachers and I had a great discussion about the implications of schema theory for teaching and learning. They immediately understood the importance of this theory for their classrooms, but they pointed out a subtlety I didn’t think about before: they often want to give students the opportunity to experience a phenomenon as a “hook” toward the beginning of a lesson or unit, and then follow up with direct instruction, etc. about the details and terminology about the phenomenon. They noted that students absolutely need the required schema before they experience the phenomena (so that they can think about it in useful ways), but they don’t need to know EVERYTHING before they get a chance to think about a concept. In fact, experiencing the phenomena and processing it as a group with their teacher can help students cement the schema in their long term memory, which they can then recall and use as they dive into the details about the concept and learn new vocabulary and concepts. Go Schema theory!


  • Bransford, J. D., & Johnson, M. K. (1972). Contextual prerequisites for understanding: Some investigations of comprehension and recall. Journal of Verbal Learning & Verbal Behavior, 11(6), 717–726.
  • Chew, S. (2022) Having Knowledge Is Not the Same as Using It, The Teaching Professor, Dec. 12, 2022

Demos for teachers #4: Task switching


UPDATED POST: my friend Steve Chew sent me information about this task switching demonstration, so I’m updating this post to include two versions (thanks Steve!)

This demonstration is a fast, foolproof way to help students and teachers experience the cost of switching between cognitive tasks. Even when it feels effortless and instant, interrupting a task costs us time and cognitive effort, even if it “just takes a second.”

VERSION #1: I found this activity on the fabulous The Learning Scientists blog (here’s a google doc version). The demonstration has a few steps:

  • Ask students to get out their phones and get to the stopwatch app (or pair students up and have them time each other on the tasks).
  • Task 1 = “Count as quickly as you can from 1 through 26. Try to time exactly how long it takes you – feel free to do this 2-3 times to make sure you get an accurate time. Write down your best time”
  • Task 2 = “Recite the alphabet from A to Z as quickly as you can. Again: try to time yourself precisely. Write down your best time.”
  • Task 3 = “Now you’re going to alternate those two tasks – counting from 1 to 26 and saying the alphabet. This will sound like ‘1, A, 2, B, 3, C, etc.’ Concentrate, don’t give up, and make sure you get all the way to 26 and Z! Time yourself and write down your time.”
  • Note: alternatively, on each of the three tasks you can as students to average their times across a few trials – good data collection practice, and a review of measures of central tendency!

It will be obvious to everyone that task 3 is difficult! Try to encourage everyone to persevere and finish task 3 – switching between task 1 and task 2 takes cognitive effort and many people will be tempted to give up.

You may want to collect the times on each task and average the times in order to compare those data with the graph at the top of the page from the Learning Scientists blog. But even before you analyze the data, everyone will notice that task 3 tasks much more than double the amount of time than task 1 and task 2.

You may want to use this experience to start a discussion about why task 3 takes so much more time than task 1 and 2 combined. Teachers and students may already understand that the term “multitasking” is problematic: we can’t selectively attend to more than one cognitive task at a time in our working memory. Some people think they are better or worse multitaskers, but it’s more accurate to think about “task switching:” some of us may be faster at switching between tasks than other people.

But no matter how quickly we learn to switch between tasks, there is always a cost! During task 3, we have to switch between task 1 and and 2. Each of those “switches” takes a very short time, and then switching back takes another additional short amount of time. Adding up all the time it takes to make those “micro-switches” each time explains why task 3 takes so much time and why it takes so much cognitive effort. By themselves, tasks 1 and 2 are simple, like many of the cognitive tasks we do daily. It’s incredibly tempting to leave one of these simple tasks “just for a moment” to get another simple task done immediately. While I was writing this paragraph, I saw a zoom notification on my phone that a school principal wanted help finding a report online, so I switched from my laptop to send her a quick email. The irony of switching tasks while writing a blog about task switching exemplifies how tempting task switching is. It’s often unavoidable, but acknowledging the cost is important. Teachers can help students realize that switching their attention to their phone , even just for a moment, has a real cost in time and cognitive effort. That realization might help us resist some of these task switching temptations.

VERSION #2: I like the simplicity of the 1-26/A-Z version but this similar activity might also be useful (thanks to Pat. O’Meara for finding this one! Adapted from this video: Try the Myth of Multitasking Exercise!)

  • Get out a sheet of paper and draw three lines across it horizontally so that it looks like this:
  • Tell students you’re going to time how long it takes us as a group to write the phrase “Task switching steals time” in the top row. Turn your paper over when you are done. Ready, Go!
  • Write about how long it took the class on the board (doesn’t need to be exact). 
  • Next task: in the next row, write the numbers 1 through 23. Turn your paper over when you are done. Ready, Go!
  • Write about how long it took the class on the board (doesn’t need to be exact). 
  • In the 3rd and 4th rows, you are going to alternate between letters and numbers. In the 3rd row, you are going to write the same phrase one letter at a time. After you write the S in the 3rd row, you will write a 1 in the 4th row. You may want to demonstrate this for them on the board. Keep doing that until you are done writing all the letters in the phrase in the 3rd row and the numbers 1-23 in the 4th row. Write legibly! Ready, Go!
  • Write about how long it took the group on the board (doesn’t need to be exact) – this last task will take them significantly longer! 

VERSION #3: Steve chew figured out that this one is the original version! Steve found out that David Meyer (U. Michigan) developed this activity and used it in his classes around 2008. Dr. Meyer’s version is similar to version 1 above, but is more concise:

  • Partner students up, one time keeping and one participating, then switch roles
  • Task 1 = count from 1 to 10, then immediately say the alphabet out loud from A-J
  • Task 2 = alternate between counting and the alphabet – e.g. 1-A, 2-B. etc.
  • Data analysis: divide the time for task 2 by task 1.
  • Ask students how many have a ratio of less than 1 (meaning that task 1 took more time than task 2) – there won’t be any!
  • Gather some “ratio” data from students (either from all students or a sample of students, anonymously if needed). Point out that if a ratio is 2, that means it took 2 times as long to do task 2 than task 1. That is the cost of task switching!

Steve included this graphic from Dr. Meyer’s class, which might be a great way to extend this demonstration into a discussion of the cost of task switching during studying!

UPDATE: Peps McCrea discussed the cost of task switching in his most recent “evidence snacks” email newsletter: “Interruptions Leave a Wake.” He shares this article at the end – useful research about the task-switching cost of classroom interruptions by announcement over the intercom, etc. Thanks Peps!