Monday, February 25, 2013

Hey! That worked! (A useful exercise on the four forces of evolution)

On the first exam in my Physical Anthropology class, I always ask either "Define genetic drift", or "Define gene flow". Every year, about half the class gets the question wrong, because they can't remember which is which. I explain the concepts in class, we do an exercise on them, they're in the book, they're listed on the study guide. Yet, every year, students confuse the two concepts.

But if students can't remember the difference, then later readings/lectures/activities on human evolution will not make much sense. (Seriously, try explaining multiregional evolution when half the class hears the words "gene flow" and thinks "Oh, like Pitcairn Island?".) 

This year, I tried something new. I created an activity that made students apply the concepts, not just see them acted out, as was the case with my old activity. And - joy of joys! - only about 15% of the students got the question wrong on the exam! Success!

Here's the activity:

Students were divided into groups of four, and given the following scenario:

You are a member of the Lovegood-Scamander Expeditionary Force, charged with tracking down the elusive Crumple Horned Snorkack (Snorkackus crumpcornius). After an arduous trek to a nearly inaccessible mountain valley in Sweden, you found the only known populations of this elusive animal, living on a series of isolated islands in the middle of a cold, deep lake. You have taken extensive notes and measurements, and your results are shown on the following slide.

Note: all of the snorkacks are the same species, but there is variation within the species by population.


I gave the students a simple map, made very quickly with Google docs. Since this activity worked well, I'll have to make a nicer one for next year.

[Drat, I can't figure out how to paste the map here.]

The students were asked to look at the variation in snorkacks as described on the map and to do the following:

1- As a group, take five minutes to describe the variation (differences) that you see in the different populations of snorkacks. You should describe only, without adding your interpretations or explanations. What was actually seen or measured about these populations?

2 - As a group, spend fifteen minutes creating at least three hypotheses to account for the variation you described. You must use the concepts of natural selection, gene flow, and genetic drift in at least one hypothesis each. (For example, you could have one hypothesis that explains the variation entirely through natural selection, one hypothesis that explains it through genetic drift, and a third that explains it through gene flow. Or, these could be combined in various ways. Just make sure you use each concept at least once.)

3 - As a group, take ten minutes to discuss what data you would need to test your hypotheses. Think widely and creatively. Do you need to take genetic samples from the populations? Do you need to measure the average temperature on each island? Make sure you know how the data would help support or refute your hypothesis.

Afterward, the students shared their hypotheses. It was a useful exercise. Not only did students apply the evolutionary concepts, but we had a useful conversation about the nature of scientific inquiry.

Best of all, students remembered the difference between gene flow and genetic drift on their exams!

Friday, February 22, 2013

How I Learned to Stop Worrying and Love a Failing Grade

I'm not the only academic who hates to give out "bad" grades (these days, that's anything below a B). Most of us were good students, and we would  have been upset receiving poor grades. We tend to project that on our students. It took me quite a while to realize that some students are simply grateful to have passed, and are not planning to put any more effort in than is necessary. It was not until recently, however, that I realized giving students bad grades can be a useful educational tool, as well as an honest reflection of the student's knowledge. Conversely, inflated grades can undermine the learning process.

For years, I had a problem in my Physical Anthropology class: the lab write-ups were "easy points", but the worst* students in the class believed they understood the class material because they did well on the lab, even when they struggled to understand the basic concepts.

The class has a huge number of graded elements, and it is a demanding class, both in content and time commitment. Since the labs were more important for the physical experience of handling the materials than they were for the write-up, I tended to give out full credit for attendance, even if the write-up wasn't strong. The labs combined for only 10% of the class grade, so these "easy points" weren't causing any problems for the overall grade distribution. 

Unfortunately, these "easy points" were leading to problems with student self-assessment. Students would assure me that their (failing) exam grades didn't reflect their true mastery of the material. As proof of that mastery, they would cite their good lab grades. And, yet, when I talked to them about the exams, it was very clear they were struggling with even the most basic class concepts.

You may be aware of the Dunning-Kruger effect, which says that - among American college undergraduates, at least - students with very low competence tend to grossly over-estimate their own mastery of the material. They believe themselves to be average or even above average in their knowledge and skills, when they are in fact in the lowest quartile, based on objective tests. (Conversely, people with high levels of knowledge and competence tend to underestimate their relative worth *cough cough* impostor syndrome *cough cough*.)

I finally wised up, re-did the labs so they required more write-up, and started grading them more honestly (i.e harshly). I don't know if this helps student self-assess and study harder, but at least I'm not encouraging students to delude themselves.
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*The "worst" students are not necessarily the ones getting bad grades, and I don't mean "worst" as a value judgement on their character. I'm referring here to student with obvious difficulties in learning the material and comprehending the concepts. Maybe this comes from poor preparation for college, lack of childhood educational opportunities, or a learning disability. These are students who are truly trying, yet failing, to do well in the class, and aren't certain why. In other words, I'm not talking about students who are clearly capable of doing well, but are short-changing their study time in order to work long hours, or be involved in sports/theater/music, or who have family responsibilities. That's a different type of barrier to student success.

Tuesday, February 12, 2013

Making the Classroom Safe for Difference

More tales from my recent workshop on Internationalizing Teaching and Learning:

One of the other faculty participants pointed out that anthropology challenges students' world-views. To which I answered, "Of course!", while rubbing my hands together and cackling gleefully. My colleague then pointed out to me that such challenges are disconcerting and make students feel unsafe and defensive.

Here's the problem: just as most academics have a hard time learning how to be good teachers because we were always good students (we wouldn't be here, if we weren't), anthropologists have a hard time recognizing how threatening it is to have your cultural perspective challenged (or even pointed out to you). After all, our reaction to our first anthropology class was "cool!" (we wouldn't be here, if it wasn't). For most of us, challenging a student's world-view is a feature, not a bug. We're trying to make the strange familiar and the familiar strange.

(Like I said, anthropology is chaotic good!)

I'm grateful to my colleague for pointing out that I need to take into consideration my students' feelings of safety, if I want them to learn and not just run away screaming.

As a result, I've developed a new classroom activity that will introduce the process of group work to my students, but also (I hope!) make the classroom a safer place to explore their own perspectives and have their worldviews challenged. 

I break students into groups of four, and have them choose their roles, based on birthdate. (The roles are leader, note-taker, time-keeper, and presenter). Then I have them discuss three questions:

1) What rules for discussion would make you feel safe to voice your opinion, no matter how unpopular or unique?

2) What rules for discussion would make you feel that your voice was being heard?

3) What do you think are the most important traits for a "good class participator" (however you define that).

After their small group time, we discuss the first two questions, and create a list of class discussion rules that will be enforced for the rest of the semester. I plan to put these on the webpage, and refer to them before each major discussion period.

Finally, we discuss the traits that make someone a good participator. The point of this is to make students aware that a) everyone has something to contribute; if you think your perspective is "strange" that just adds to the richness of the class; and b) the most successful participators are those who open their mouths and do it.


Hopefully, this will help with the "anthropology is scary" problem.