Thursday, June 23, 2011
A recent study from University of Washington professors compared two approaches for teaching large introductory biology classes: 1) traditional lecture method, and 2) “active learning” without lecture. Eliminating lecture does not in itself improve teacher-student ratios. Indeed, some have said it doesn’t matter whether one lectures to 20 students or a thousand.
What is important is to address the question of what happens to educational quality if you reduce the number of teachers. There is certainly no evidence that increasing the number of students in a lecture hall will improve teaching effectiveness, and in fact the opposite is likely. Statistically, increasing class sizes in lecture courses has a disproportionate deleterious effect on socio-economically disadvantaged students. So, as number of teachers decreases in response to economic necessity, we can expect the educational gap to grow between advantaged and disadvantaged.
So, how should educators respond to having more students and fewer teachers? The educational literature has been building for decades toward the conclusion that lecturing is a poor way to teach. We teachers know about many alternative “active learning” strategies, but just don’t use them much, because lecturing seems so intuitive and for most of us, it has become a habit. And lecturing is the environment in which most of us were trained.
In the U. Washington study, the professors compared grade performance in classes based on lectures with classes based on active learning. The type of active learning they used included pre-class reading quizzes, daily multiple-choice “clicker” questions, a peer group instruction format that included so-called “constructivist” learning exercises, and weekly practice exams. Also, they adjusted learning requirements to require more creative and critical thinking, since most college students have little experience with higher cognitive tasks of synthesizing and applying learned material in new contexts (as specified in Bloom’s taxonomy of learning). The learning activities went beyond the lower levels of learning vocabulary and understanding of concepts.
Large student populations were involved for both comparison groups, and the classes studied spanned several semesters. Student performance was measured in terms of difference from the predicted performance based on college grades prior to entering this biology class and SAT scores (which are highly reliable predictors, based their previous analysis of five year’s of class data). This analysis also revealed a reliable prediction that disadvantaged students were twice as likely to fail this course than non-disadvantaged students.
Not surprising (to me at least) was the consistent result of better final grades in the classes that had active learning instead of lectures. The benefit was especially noticeable on exam questions that demanded higher-level thinking. Moreover, the disadvantaged students improved disproportionately.
The authors did not examine possible explanations for why active learning yielded better results than lecturing. I think the explanation is obvious, based on what I know about mechanisms of learning and memory. First, learning from lectures requires sustained paying attention, but a whole generation of multitasking students has emerged who are not very adept at sustained attentiveness. Accordingly, the short attention spans of these students make it difficult for them to be engaged with the lecture content. Engagement lies at the heart of effective learning.
Secondly, active learning requires more engagement because the students have to “do something” instead of just listen. They have to find, assimilate, and use information to solve problems — all of which enhance understanding and are effective memory rehearsal strategies. The social dynamic of student learning teams facilitates these activities. It is much harder to drift off task, daydream, or sleep in class when a student has to interact socially with peers to perform a learning activity.
These ideas have been advocated for several decades. But now, it seems imperative for teachers to use these approaches in an age where there will be fewer teachers and where more students are unable to benefit from lecturing. This requires for many teachers a sea-change in teaching attitude and strategy. It is no longer suffices for a teacher to be a source and dispenser of information. Information already exists in many places, text books, Web sites, and videos, often in better presentation form than a typical teacher can produce. Even the expected role of teachers in explaining everything is problematic. Students remember much better that which they have to figure out. Working in groups makes it easier to figure out difficult material. Students can often explain things to each better than teachers can because teachers have more difficulty in knowing why students are having a comprehension problem.
The teacher must become a manager of learning activities. This means structuring in-class time so that students work collaboratively on learning activities. Students also need homework that gets beyond “busy work.” And, as I have been advocating for some time now, students will benefit from more frequent testing, especially under lower-stakes conditions.
Effective managers are those who can “scale up” to manage more and more people. We can’t wait for a new generation of teachers and professors. We need professional development programs now that emphasize management of student learning.
Haak, D. C., et al. 2011. Increased structure and active learning reduce the achievement gap in introductory biology. Science. 332: 12131-1216.