You may have seen this post in Slashdot a couple of days ago. It points to an article talking about the research of Australian educator, John Sweller. Sweller developed the “cognitive load theory” which explains how our brains handle new information. He says our working memory can only hold two or three tasks at a time. These tasks are only retained a few seconds. Without rehearsal anything new is gone in about 20 seconds.
Key points about Cognitive Load Theory:
- Working memory is only limited when you’re learning new information. Once information is in long-term memory, it can be brought back to working memory in very large amounts.
- In a classroom situation, only limited material is going to be retained, unless notes are taken or handed out.
- Power-point presentations can backfire if the information on the screen is the same as that which is verbalized, because the audience’s attention will be split between the two.
PowerPoint should be reserved for diagrams, pictures and graphics that are not easily explained with dialog.
Professor Sweller states that the worst PowerPoint presentation is one that is read to students. According to his research, our brains can’t handle reading while listening to someone else read the same material. I won’t be telling this to my pastor who asks everyone to bring a Bible each Sunday for the sole purpose of reading along with him.
I must admit that a presentation where a PowerPoint is read word-for-word is terrible. Guy Kawasaki said it best…
…as soon as the audience figures out that you’re reading the text, it reads ahead of you because it can read faster than you can speak. The result is that you and the audience are out of synch.
Don’t be a Bozo. If you are going to read your PowerPoint, give everyone a handout and send them home. Your audience will be better served.
My earliest recollection of reading in class was in first grade. We all had the same book. We all read the same words aloud together. I remember doing this in every grade through high school. As freshmen I know we read one of Shakespeare’s plays during class. I think it was MacBeth. We did the same with Romeo and Juliet in tenth grade. Shakespearian English was certainly something new for my brain in high school. No wonder I didn’t understand it.
Sweller adds another thing in the article. He says we should not present students with new problems to be solved. We should instead show already-solved problems to them when introducing new information.
The only option we have is to pile on the homework and have the students come to class with much of the material already in long term memory. I’m not sure how that fits with the ban on homework.
I remember freshman chemistry with Dr. Haight. This was long before anyone had ever heard of PowerPoint. Dr. Haight read his notes to us while he wrote them on the board. The man was a speed writer. It was all we could do to keep up with his writing. There certainly wasn’t time to think about what we were writing. For the second semester of freshman chemistry I had Dr. Sadurski. His approach was completely different. His notes were neatly printed using color coordinated markers on overhead transparencies. He would drop a sheet on the overhead and talk about it. We would write as fast as we did the first term, trying to finish before he flipped to the next slide.
I learned chemistry from both of these instructors. The information I was given in class was complete enough that I could go over the notes and do the homework and prepare for the exams. If one of them had used PowerPoint, I think I would have still learned the same amount of chemistry. Most of what I learned as an undergraduate was learned outside of class using materials I acquired during class. I heard it. I saw it. I wrote it down. All those things helped me understand it.
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