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 4: Technology   6: Myths   Contents 


Lectures: Problems for Students and Teachers

Our reliance on lectures is the most glaring example of the problems plaguing education. Lectures are so futile that I would feel foolish describing their inadequacies if they were not so pervasive. Everyone recognizes the basic lecture model: a teacher stands at the front of the room, while students sit quietly taking notes. At university there is no attempt to disguise this model. With enrollment for some classes in the hundreds, there is little chance to do much else. A walk through the halls of any high school will confirm that lecturing is the predominant model there as well.

The biggest problem with lectures is that they are inherently ineffective because they involve groups. Students bring to class different backgrounds, experiences, interests, and aptitudes. It is impossible to meet the optimal learning pace of all students because one teacher cannot deliver dozens of customized lessons simultaneously.

Teachers do their best by teaching to the “middle of the class”. But in trying to meet the needs of all students, they meet the needs of few. Slower students are left behind, while faster students are left twiddling their thumbs. The time of both groups is wasted. However, this is a simplistic analysis. Students are not so neatly sorted into slow learners and fast learners. In reality, each student finds certain topics easier, relative to the rest of the class. There are three layers of student differences: general student ability, specific topic ability, and the minute-to-minute variations in a student’s focus. Together, these make it impossible for lectures to meet the optimal learning pace of all students at all times.

Some people talk in their sleep. Lecturers talk while other people sleep.

– Albert Camus

If you had 8:00 AM lectures in university, as I did, you know that there is not much learning going on if you are tired – or at home in bed. Students frequently miss class. Conversely, a student cannot be absent from an audiotape, videotape, book, or computer program since these media reveal their content only when a student is ready to learn. Even students who attend class can miss critical ideas when their focus fades. We’ve all had our attention diverted in a meeting or lecture. Our mind wanders to relationship problems, what to eat for lunch, or the names of the Seven Dwarfs. If we lose focus while reading a book or viewing a video, we need only backtrack or rewind to regain our place. However, since lectures travel in only one temporal direction, students can miss critical concepts and remain lost. (In case you were wondering: Bashful, Doc, Dopey, Grumpy, Happy, Sleepy, and Sneezy.)

Another reason lectures are inefficient is that they are spontaneous. Lectures are not scripted, rehearsed, and edited like books, videos, and software. In writing this book, I have made countless edits – deleting sentences, paragraphs, and even entire chapters because they were redundant, unimportant, or misleading. Lectures contain pauses, inaccuracies, backtracking, and unnecessary embellishments that contribute to their inefficiency. But scripting lectures is not the solution.

If lectures were scripted, besides being more accurate and seriously boring, they would remain inefficient. Our brains can process information faster than we can vocalize it. Researchers in the somewhat bizarre field of “time-compressed speech” routinely shrink audio recordings to 50% without any decrease in comprehension (savings are achieved by deleting pauses and speeding playback). Similar improvements can be achieved by replacing audio with text.

The ear cannot skim in the temporal domain the way the eyes can browse in the spatial domain.

– Barry Arons

High school students can read twice as fast as teachers speak. On average, teachers lecture at 111 words per minute (plus 17 wpm from students, for a total of 128 wpm). Videotaped lectures, created as instructional aids, also typically have rates near 125 wpm. Conversely, average silent reading rates are 205 wpm in ninth grade and 250 wpm in twelfth grade. Even higher rates can be achieved, albeit with reduced comprehension, when text is scanned or skimmed. This is an indispensable strategy. Readers constantly make adjustments depending on their familiarity with a topic, the difficulty of a passage, and their reasons for reading. Listeners cannot make similar adjustments to slow or hasten live speech.

Another factor that contributes to the inefficiency of lectures is notetaking. Although lectures proceed at 125 wpm, students can only copy notes at 20 wpm. To accommodate notetaking, most of what a teacher says cannot be worth recording; otherwise, students would not be able to keep up. Teachers must incorporate enough embellishment, redundancy, and waste to ensure that 20 written words can summarize 125 spoken words. By this measure, lectures that allow notetaking have a theoretical maximal efficiency of 16% (20 wpm ÷ 125 wpm).

The true level of efficiency – whatever it is – cannot be very high since students who skip lectures suffer no ill effects when given instructor’s notes. This was the finding of one classic experiment. Groups of students viewed a 20-minute lecture – one group took notes while another group listened. A third group did not attend the lecture at all. Two days later, all students were given 25 minutes to study from a set of instructor’s notes before taking a test. Scores were the same, regardless of whether students had attended the lecture. In other words, the original lecture had been a complete waste of time.

Another study, with a similar protocol, arrived at the same conclusion with a 30-minute lecture followed one week later by a 15-minute review of instructor’s notes. Once again, the lecture was a complete waste of time. The authors concluded, “The present data raise a question about the function of the lecture itself. Since students who did not attend performed as well as those who did … the lecture per se may be a redundant vehicle for communicating substantive information.”


next: Problems with Grades


This is an excerpt from Chalkbored. Order the book here to learn more about ...

- Time in school versus time spent learning
- The role of classroom questions (from students and teachers)
- What research reveals about the effectiveness of notetaking
- Alternatives to lectures: discovery learning, cooperative learning, and individualized instruction