Tag: research

Making memories stick. With Play-Doh.

My boss, Carl Wieman, likes to describe what we do as “looking for the pattern of how people learn science” (as he does in this video.) And the places to look are classroom studies, brain research and cognitive psychology. I certainly agree with the first place – that’s teachers and teaching. And research like this, that and this other thing about how the brain physically changes while you learn in very cool – that’s science. But cognitive psychology? I’ve been a science geek since, well, since before I can remember anything else, so I really haven’t been exposed to psychology and those other disciplines they teach on the “Arts” side of campus.

Carl says it’s important, though, and I trust him, so my colleagues and I read a cognitive psychology paper for our CWSEI Reading Group “What College Teachers Should Know About Memory: A Perspective From Cognitive Psychology” by Michelle D. Miller (College Teaching, 59, 3, 117, (2011)). Here’s a link, if you have access from where you’re clicking.

The paper is a nice summary of the models of memory. Short term, long term, working memory, ecological (or adaptive) memory. Here’s my interpretation. Every bit of information that’s stored in memory is accompanied by “cues”. Think “tags”, like the ones that accompany this blog post. When you see the cues, you recall the memory, just like finding blog posts by clicking on a tag. Without the tags, finding posts means paging through the archive. With a tag, you can zero in on the post. And the more tags on the post, the easier it is to find. Same with memories: the more cues linked the memory, the easier it will be to recall later.

Not all cues are created equal, though. As Miller puts it,

[u]nderstanding the role and importance of cues enables a richer and more accurate understanding of why people remember — and forget — what they do. (p.119)

Miller carefully crafted descriptions of the kinds of cues that trigger recall, so while I’m cutting them into a list and adding some bold, these are Miller’s words (p. 120):

Here are what I believe to be the cues that trigger us to “tag” information as being survival-relevant:

sensory impact, termed vividness: Concrete information that comes accompanied by sound, visual qualities, even tactile sensation tends to be more memorable than abstract information. Visual information is particularly salient to human beings, so that anything that can be visualized tends to be particularly memorable.

emotional impact is another cue that incoming information warrants long-term storage. Consider situations that relate to survival in a “natural” setting—a sudden danger, a new food source, encountering an enemy—and all would come accompanied with an emotional “charge.”

relevance to one’s own personal history is another indication that information will be useful in the future

structure and meaning—the ability to interpret information and put it into context—helps us distinguish useless background clutter from information that we need to keep

personal participation, as contrasted with passive exposure. This will come as no surprise to those familiar with the “active learning” trend. If we watch someone else do something, that activity may or may not be relevant to us, and it we will likely opt not to form a detailed memory of it. However, if we ourselves carry out the action, there is a greater likelihood that we will need to learn from and recall that experience later. We may also encode a richer set of cues when we are actively involved, which increases the likelihood of retrieving the information later.

Don’t you love it when you read an article that concisely and explicitly describes all those things you feel, in your gut, are important? It’s times like this that make me re-evaluate my naive and, frankly, prejudiced view of psychology, “C’mon, how can you possibly know how humans work?” “Oh, like that, ” he says, sheepishly. “Um, thanks. That’s cool!”

The week my colleagues and I read this paper, I was preparing the next activity for an introductory, general-education astronomy course I work on. This activity, like the others I’ve written and am sharing through the Astro Labs page on this blog, is a chance for “Astro 101” students to get some hands-on interaction with astronomy. Up next was the activity on black holes, especially spaghettification.

“Spaghettification”?

Talk about a made-up word, huh. Not by me, mind you. Chat with any astronomy instructor and you’ll find we all know exactly what it means because it’s the perfect word to describe what happens if you fall into a black hole.

<astronomy lesson>

A black hole with the mass of the Earth would only be about the size of a grape. Imagine it this way: if you could pack together and compress the entire Earth down to the size of a grape, the force of gravity would be so strong curvature of spacetime would be so high that not even light, traveling outwards as the speed of light, could escape.

That describes trying to get out a black hole. What about falling in? Let’s imagine you’re 2 metres tall and your lying on your back with your feet 2 metres from the black hole and your head 4 metres from the black hole. You can see it down there, between your feet, a little shiny grape a couple of metres away. It’s okay to think classically here, for a moment. Gravity is very strong but, being an inverse square law, it drops off quickly: your head is 2 times farther from the black hole than your feet so the force of gravity is only 1/4  as strong. What do you suppose happens when the black hole pulls 4 times harder on your feet? They get ripped off, that’s what. Your body gets stretched out as your feet accelerate towards the black hole, leaving your knees, hands, chest and head behind. This difference-in-forces is called a tidal force because these same kinds of forces occur in the Earth-Moon system where the Moon yanks on the water on Earth’s near-side and leaves the far-side water behind, giving us the tides. Newton worked that one out for us, more than 300 years ago.

The force of gravity between the Moon and the water on the near-side of the Earth is stronger than the force between the Moon and the more distance, far-side water. Earth's watery skin is deformed, giving us the tides. (Graphic: Peter Newbury CC)

Meanwhile, back at the black hole, the hapless astronaut is being pulled down a little funnel that ends up on the grape-sized black hole. Happy astronaut one second, long and skinny piece of spaghetti the next. Spaghettification, baby!

</astronomy lesson>

Ouch, that’s gotta hurt! LOL. Yeah. But how do we get Astro 101 students to remember it a month from now on their exam? Play-Doh, that’s how. Our activity progresses from setting up the phenomenon of tidal forces, to sample calculations demonstrating tidal forces are real, to recreating the spaghettification of a Play-Doh astronaut.

An astronaut falling into a black hole, before spaghettification...
...and after!

Here’s where the part about memory comes in. Students are potentially reluctant to play with Play-Doh. This is University. We’re not Children anymore. Teaching assistants and instructors are equally reluctant to ask students to play with Play-Doh. “Why,” they wonder, “should I?”

Because, I tell the teaching assistants who, if necessary, relay it to the students, it will help you remember. Playing with Play-Doh, stretching the poor astronaut’s legs, often pulling them right off his body, and squishing the Play-Doh into to a narrow strip, is tactile. And emotional – you just ripped his head off, dude! It gives relevance and a physical structure to those calculations. And it takes personal participation – oops, I just pulled his leg off!

Good in theory but how about in practice? The activity ran. The teaching assistants sold it. The students did it. All of them! Now we just have to see if they (1) learned anything and (2) can remember it. For (1), one of the questions they answer at the end of the activity is, “In your own words, describe what happens to the astronaut. Why do you think it’s called ‘spaghettification’?” Here’s one student’s answer, typical of many I thumbed through:

as the astronaut falls toward the black hole, feet first, its body stretches as it nears the black hole. the closer body parts (feet, then hands) stretch faster and fall faster than the head and body. It’s called spaghettification because the legs and hands stretch elongate like spaghetti.

Yep, I’ll take that. Would have been nice to see the word “tidal” in there but he did make the connection between closer and faster. For (2), we’ll be sure to put something on the final exam that tests this material. I’ll let you know in 4 weeks.

As my pop likes to say, “learn by doing.” Let’s update that to, “remember by doing.”

Why should I use peer instruction in my class?

Image: "Lecture Hall," uniinnsbruck, Flickr (CC)

[Update (June 16): Lead author Zdeslav Hrepic pointed me to a follow-up book chapter [PDF] where he and the study co-authors describe using tablet-PCs to counter the problems uncovered in their study. Thanks, Z.]

I’m sure we’ve all heard it from skeptical instructors: Why should I use peer instruction in my class? In response, we often cite Hake’s 6000-student study or the new UBC study by my colleagues Louis, Ellen and Carl. These are still pretty abstract, though: If you use interactive, learner-centered instruction, you can expect your students to better grasp of the concepts.

“Sure, but why?” the instructors ask. “Why does it work?”

I just read a paper that can help answer that question. I ran across it while following a discussion about the Khan Academy videos and whether or not they are good tools for learning. This paper by Hrepic, Zollman and Rebello (2007) asks students in an introductory physics course and physics experts (with M.Sc’s and Ph.D’s) to watch a 15 minute video of a renowned physics educator presenting a topic in physics.

The researchers do a series of pre- and post-tests and interviews with the students and experts to compare their understanding of the concepts covered (or not) in the video. There were some significant differences. A couple that stick in my head. (1) students recalled learning about concepts that were not presented in the video. (2) Only students who knew the correct answers on the pre-test were able to infer the concepts from the video (that is, the questions were not explicitly answered in the video.) The students who did not know the concept before were unable to make the inferences. Like I said, there are significant differences between what the instructor thinks a lecture covers and what the students think is covered.

The paper nicely gives us some suggestions to counter this problem.

And my thoughts about how to use peer instruction to do that.

Making inferences: Experts make more inferences than students. And only students who already know the concepts can infer them from the lecture. Therefore, instructors need to be cautious about relying on students to fill in the blanks.

Some of the best peer instruction questions are the conceptual questions where the answer is not simple recall. No traxoline here, please. Questions that rely on students making inferences are excellent for promoting discussion because it’s likely students will interpret the question differently, make different assumptions and come to different conclusions. <soapbox> All the more reason that students need to first answer clicker questions on their own so they’re prepared to share their inferences. </soapbox>

Prior knowledge: Students’ prior knowledge influences what they perceive and can “distort” their recollection of what the lecturer says. Therefore, it’s essential that the instructor has some idea of what the students already know (particularly their misconceptions) before presenting new material.

A few, introductory clicker questions will reveal the students’ prior knowledge. Sure, maybe these are simple recall questions that won’t generate a lot of discussion. But the students’ responses will inform the agile instructor who can tailor the instruction.

Continuous feedback about students’ understanding: The trail the instructor blazes through the concepts and the path the students follow often diverge during a lecture. The instructor should be continuously gathering and reacting to feedback from the students about their understanding so the instructor can shepherd the students back on track.

Observant instructors can gather critical feedback from the discussions that occur during peer instruction or the students answers on in-class worksheets like the Lecture-Tutorials popular in introductory “Astro 101” classes and other hybrids of the Washington Tutorials. Rather than waiting weeks until after the midterm or final exam to find out students totally missed Concept X, the instructor can discover it within minutes of introducing the topic. Minutes, not weeks! The agile instructor can immediately revisit the difficult concepts. Immediately, not weeks later or never!

I’m much more confident I can answer the skeptical instructor now. “Why should I use clickers in my classroom?” Because they give the students and you to ability to assess the current level of understanding of the concepts. Current, right now, before it’s too late and the house of cards you’re so carefully building come crashing down.

An astronomy education retreat

Last year, Tim and Stephanie Slater phoned me up and invited me to be part of an astronomy education research group they were putting together. I was flattered to be part of the Conceptual Astronomy and Physics Education Research (CAPER) team! Especially when I learned who else I’d be working with. I mean, check out the bio’s of these remarkable astronomy educators. I’ve got to admit, I was a bit overwhelmed by their experience (and publication records.)

We got together at a conference we all attended and meet via telecon regularly but this week was special. A group of us — Tim, Stephanie, Julia, Sharon, Kendra, Inge, Eric and I — got together in Colorado for an intensive, 3-day astronomy education research retreat.

Wow.

We talked about this. We argued about that. We thought about this and that. And it was all about teaching and learning astronomy. Not marking or Little League or home renovations or all those other things that eat up our time. Just astronomy education. What a treat!

By the end of the 3 days, we’d developed a research project, from concept tests and interview protocols to IRB letters and pre/post testing schedules. And what’s it all about?

Understanding certain concepts in introductory astronomy, like the causes of the seasons and the phases of the Moon, requires students to visualize the Earth, Moon and Sun, from both Earth-centered and Sun-centered points-of-view. It seems likely, then, that students with better spatial reasoning abilities will be more successful. There are already  standard tests of spatial reasoning. And there are a number of assessments of astronomy knowledge, augmented by the one’s we created this week. Add some pre-/post-testing and a dash of correlation coefficient and see what comes out.

One of the concepts we want to explore is the motion of the sky, so we made up an assessment using this diagram.  (I’m using this example because *I* created this diagram with Powerpoint and a little help from Star Walk.)

Looking south at sunset. So many questions we can ask...

Like I said earlier, I was pretty overwhelmed by the calibre of the other people in the group. So it was very gratifying, good for my ego, to be able to contribute and realize that we all have strengths. Maybe that’s the humble Canadian coming through.  I’m excited about what we’ve done and what we’ll be doing. And proud I have knowledge and experience to share.

I can’t wait to see what we find. Stay tuned!

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