Why Long Lectures Are Ineffective

If students can only focus for 15-minute intervals, shouldn't we devote precious class time to something more engaging?

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Each school day, millions of students move in unison from classroom to classroom where they listen to 50- to 90-minute lectures. Despite there being anywhere from 20 to 300 humans in the room, there is little actual interaction. This model of education is so commonplace that we have accepted it as a given. For centuries, it has been the most economical way to “educate” a large number of students. Today, however, we know about the limitations of the class lecture, so why does it remain the most common format?

(MORE: Should Teachers Be Allowed to Share Their Lesson Plans?)

In 1996, in a journal called the National Teaching & Learning Forum, two professors from Indiana University — Joan Middendorf and Alan Kalish — described how research on human attention and retention speaks against the value of long lectures. They cited a 1976 study that detailed the ebbs and flows of students’ focus during a typical class period. Breaking the session down minute-by-minute, the study’s authors determined that students needed a three- to five-minute period of settling down, which would be followed by 10 to 18 minutes of optimal focus. Then — no matter how good the teacher or how compelling the subject matter — there would come a lapse. In the vernacular, the students would “lose it.” Attention would eventually return, but in ever briefer packets, falling “to three- or four-minute [spurts] towards the end of a standard lecture,” according to the report. This study focused on college students, and of course it was done before the age of texting and tweeting; presumably, the attention spans of younger people today have become even shorter, or certainly more challenged by distractions.

Middendorf and Kalish also cited a study from 1985 which tested students on their recall of facts contained in a 20-minute presentation. While you might expect that recall of the final section of the presentation would be greatest— the part heard most recently — in fact the result was strikingly opposite. Students remembered far more of what they’d heard at the very beginning of the lecture. By the 15-minute mark, they’d mostly zoned out. Yet these findings — which were quite dramatic, consistent and conclusive, and have never yet been refuted — went largely unapplied in the real world.

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Even Mittendorf and Kalish themselves did not take these findings to their natural conclusions. Having established that students’ attention maxed out at around 10 or 15 minutes, they did not question whether hour-long lectures should be the dominant use of class time. Instead, they recommended that teachers insert “change-ups” at various points in their lectures, “to restart the attention clock.” This may have been a pragmatic incremental step, but if attention lasted 10 or 15 minutes while passively listening, it is questionable why valuable time in classrooms with teachers and peers should be devoted to lecture at all.

With the Internet, lectures can in fact be divided up into shorter, sub-15 minute sessions, and be delivered outside the classroom. So what do we do with that class time? Here we can take inspiration from the humanities seminar, where any “information delivery” happens outside the classroom through student reading, allowing class time to be entirely devoted to teacher-moderated discussion. This also happens in many business schools, where students read a case study ahead of time and the teacher leads a conversation about the issues facing the company or executive described in the case. With engineering or science, class time can be used for students to collaboratively tackle more challenging questions or projects. The main point is that when humans get together to learn, we should replace passivity with interactivity.

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When we free ourselves from the notion of one person delivering information at the front of a classroom at a set pace, it allows us to completely rethink our assumptions of what a classroom or school can be. We could then consider having multiple teachers in the same room working with students of multiple skill levels and age groups. A bell would no longer need to be rung to artificially stop one subject and to start the next. Ironically, by removing lecture from class time, we can make classrooms more engaging and human.

MORE: How to Get — And Keep — Someone’s Attention

39 comments
jamal1499
jamal1499

@h_altabtabai وعندما يرى طالب غير فاهم او شت تفكيره يخرج التطبيق ويعطيه مثالاً فيما يحب ويدخله في عالم الفيزياء العجيب ومنها عشقت الفيزياء

jamal1499
jamal1499

@h_altabtabai اذكر عندما كنت ادرس بماليزيا دخل علينا بروفيسور ليعلمنى فيزيا فطلب ان تمليء تطبيق فيه العديد من الاسئله منها "الهواية" يتبع

kristadg
kristadg

Khan

is right on the money. Being a college student myself, I find long, monotonous

lectures to be extremely boring. No one is going to look forward to a class

that sends them into daydreams or even to sleep. I find it easier to focus when

I am multitasking or interacting. If you look around a classroom during a

lecture, you will see a majority of the students playing with their phones or

doing something to keep them entertained. Lectures are not benefitting students

in any way unless they are able to stay concentrated and take notes. So, why

bother? I think teachers/professors see lecturing and note taking as a teaching

method that we all must learn to accept. But, if the majority of the students

are not able to learn this way, then I don’t think it should be enforced.

The

article points out that most students are only able to focus for 15-minute

intervals before they zone out. I believe this is a result of our society.

Everything around us is expected to be entertaining. We hold that standard to

our schooling experience. I don’t think that is right, but it is the way the

world is now. Just walking around campus you will see students listening to

their iPod, checking their cell phone, and doing homework on their laptop all

at the same time. Another example could be something as simple as watching

television. When you turn the TV on you look for something that interests you

and keeps your attention. As soon as it starts to bore you, you change the

channel, right? In our society today, we feel the need to constantly be stimulated.

So, when our class time becomes boring and isn’t keeping our attention, we will

naturally find other methods of occupying our mind. I understand that it can be

difficult to teach an engaging and interactive lesson to a classroom full of

one hundred or so students. On the other hand, I think teachers should conform

to the way society is now and teach students in a way that is beneficial to

them and their grades.

adam_onge
adam_onge

People like Khan appeal to the masses with average mediocre minds, but fortunately (or unfortunately, according to your political disposition) the 99% (not 47% as Romney said) of the human population is rather irrelevant (except during elections) in the long run. Only +3*sigmas (Black Swans?) count. LOL

John Golden
John Golden

"Lectures are ineffective, let's have shorter or smaller lectures." Not exactly breakthrough thinking. In addition to perpetuating unhelpful math ideas, Mr Khan is perpetuating unhelpful teaching ideas.

Brown_Dog
Brown_Dog

Khan notes: "Even Mittendorf and Kalish themselves did not take these findings to

their natural conclusions. Having established that students’ attention

maxed out at around 10 or 15 minutes, they did not question whether

hour-long lectures should be the dominant use of class time. Instead,

they recommended that teachers insert “change-ups” at various points in

their lectures, “to restart the attention clock.” This may have been a

pragmatic incremental step, but if attention lasted 10 or 15 minutes

while passively listening, it is questionable why valuable time in

classrooms with teachers and peers should be devoted to lecture at all."

If an athlete tires after training at full capacity for ten or fifteen minutes, would asserting that there is no value to devoting training time to full capacity training over short intervals follow as a "natural conclusion?" It would if the person making the claim cannot understand what constitutes relevant evidence and how to use such evidence in a logical argument.

Surely Khan knows about the evidence-based research that shows class periods that employ short periods of instruction ("lecture-discussion") punctuated by well structured personal interactions with other humans have proven to be very effective.

This reader wonders why Khan chose a 14-year old contribution to good practice by two well-respected contributors and presented their work out of context as an example of shortsighted reasoning and failure to question. There was nothing shortsighted about that 1996 work. Subsequent evidence shows that they were indeed describing effective classroom practice.

Cammie Byerley
Cammie Byerley

I'm getting a PhD in math education and taught high school math for four years and university Calculus for two more.  Khan has some fantastic ideas about distributing education using technology and is good at mathematics.

However, when I watch his videos on topics such as slope and proportions, I can see that they are likely to promote the same misconceptions that are widely documented in math education literature. I don't take offense to the ideas of clearly and directly telling students a meaning you hope they will develop for a mathematical concept. However, I believe that what students often learn from Khan is not identical to the mathematics he has in his head. This is sometimes clear from the students' comments because they ask questions that make it clear that they didn't understand what he said and were just trying to figure out where to move the symbols and numbers on their homework to get an answer.

For example, I believe Khan understands that if a slope is 7.3, this means that a change in y is 7.3 times as large as an associated change in x. I believe that he knows this change in x could be of any size. However, I frequently interview college students and high school math teachers who believe that if the slope is 7.3 that you go up 7.3 in the y direction for every time you go over 1 in the x direction. These meanings may seem identical for people who understand slope well, but often math teachers and students are unable to predict any of the points in between the ones they get from the up and over process. I often talk to high school math teachers and university students who cannot distinguish between a rate of change and a change in y values because they are used to the slope being measured for a unit change in x. There is also research evidence that high school math teachers do not always know why you divide in the slope formula. They think of the fraction bar as separating the number that tells you "rise" and the number that tells you "run." To clarify, you divide because division gives you a measure of the relative size of a change in x and an associated change in y.

I'm currently taking science and statistics courses and focusing on the meanings for rate of change that I use in these classes. In my geophysics course it is essential that slope doesn't not mean rise over run because most of our computations are in three-dimensional polar coordinate systems. A change in independent variable is not associated with an "rise" motion on the graph. When faced with polar coordinates, university students still assume that slope is horizontal rise over vertical run because of what they learned in school.

In statistics slope is essential for interpreting the correlation coefficients in linear regression. To understand what the situation is modeling we need to know that this coefficient gives a relative size of changes in two variables.

Calculus students I've researched often think of rate of change as "the change in y's per 1 unit change in x." They primarily focus on the change in y's as the rate of change and actually don't know how to determine what constant rates of change look like if the changes in x are of different sizes. For example, I gave the student measurements for the weight of a puppy after 1, 2 and 4 weeks and he said he couldn't determine if it the puppy had the same average rate of change in each interval because the intervals were different sizes. In the definition of the derivative it is essential to consider arbitrarily small changes in x and compare the relative size of changes in y. This would require a multiplicative meaning for division and fractions.

Khan typically assumes that when he says "divide" that high school students will understand what that means with respect to the quantities involved. However, in my research on Calculus students I find that even people who have received all A's and B's in secondary mathematics can't explain what a quotient means. For example A is A/B times as large as B, would be a statement that they couldn't reproduce. Others can't explain that A/B tells you the size of a group if you divide A objects into B groups. There are multiple meanings for fractions and division and often the ones they have are almost primarily related to the formulas for computing quotients. These meanings for fractions and division are helpful in understanding slope, but most students I talk to have very weak foundational meanings. If I was making videos to teach slope, I would take into account my learner's current knowledge as well as the meanings that I knew would be useful in future courses.

I know that some math educators do not like Khan's work because he is "telling" students what to do. I actually don't mind that aspect at all, but I wish that the meanings he promoted for the critical idea of slope were consistent with meanings that would be useful in statistics, calculus and science. It would make me very happy if Khan and math educators could work together to make videos that take advantage of math education research findings on how students learn math. Both groups have a lot to learn from each other. Khan's immediate impact on students is much greater than most math educators, and most math educators would have better ideas about what students might be taking away from his videos. Even our best states and affluent schools are still doing poorly in math compared to countries in Asia. Our entire tradition of math instruction is deeply flawed, and unless Khan provides videos that break free from traditional methods of teaching math, he will continue to reinforce the current culture where kids can find answers to certain problems but don't know what the computations mean.

Paul Dawkins
Paul Dawkins

My main concern with Khan's whole analysis is that he still assumes students essentially need lectures because he frames the problem as "when can we get lecture in." At least this seems to be implied by his justification of online delivery because online lectures allow students to view them in 15-minute segments. Speaking as a mathematics educator, I would instead focus more on the goal that students learn through engaging in mathematics activity rather than being told about other people's math understanding. Extended periods of speech by the professor need only come intermittently and only for the purpose of eliciting, connecting, and summarizing students' ideas. The problem I find is more with the culture of "telling" in schools which Khan seems to ultimately maintain. He only says we can use a new medium to tell students what they ought to know. Plenty of mathematics education research reveals just how ineffective "telling" really is, even when it is clear and comes in small doses. 

Carolyn Fitzpatrick
Carolyn Fitzpatrick

If students won't pay attention to a lecture in the classroom with the teacher right there, what makes you think that they will pay attention to a recorded lecture among the distractions of phone, friends, siblings, TV, jobs, chores, and video games? A flipped classroom can work well  with the right group of kids. But too often everyone shows up the next day without having watched the video or done the reading, and then your activity for the day is screwed.

Geoff
Geoff

You couldn't find an image of a *university* classroom to accompany the article?

Gay_Chevara
Gay_Chevara

Think about Chinese students in middle school, high school and university.  They have nothing but lectures in 50-minute sessions all day.  That's the way they do things.  Rote learning, information given out in a droning fashion by the teacher, while the students sit in the same seat in the same classroom all day from 8:00am to 4:00pm.

Tony Adams
Tony Adams

Really? ... the 'best and the brightest of youth' (i.e. college students) can only focus for 15 minutes at a time?  Wonderful. I can't imagine how in the WORLD they will EVER manage to "focus" in a fullt-time job for 8-+ hours a day.

This is hilarious!

Dan Bruce
Dan Bruce

I had a professor in college who kept a roomful of us 19-year olds spellbound for an hour each day with his lectures on advanced differential equations. He lectured for forty-five minutes, then patiently answered questions. His knowledge of his subject and his method of presentation was the equivalent of a well-tuned symphony. Teaching is an art. We need more "artists" in the classroom. By the way, that professor was known for being one of the strictest graders at my university, but everyone passed the course that semester and most made an A because they knew the material so well. More important, we learned how to think logically by watching and listening to a master do it out loud in front of us.

Lindsey C
Lindsey C

This is why coming to university encouraged me to buy a Dictaphone. A truly fantastic resource when combined with the Powerpoint slides that sometimes don't make so much sense without the lecture recordings.

JohnnySmith0
JohnnySmith0

Even watching people interact in a class every 10 minutes or so, is effective. It gets them thinking. And thinking is a way to learn. Just listening is not learning. If you just listen then you're going to forget.

Carl Manner
Carl Manner

there are all sorts of devices and technological 'solutions' designed to engage students in lectures. As a student, I disdain using them and paying for them. 

Frankly, if you aren't committed enough to your education to stay tuned in for a 50-90 minute lecture, you shouldn't be there. It requires discipline and effort to stay fully engaged for such a duration, but it can be done. 

Insofar as utilizing technology for didactic purposes, help me hear and help me see. For a big lecture, give me a doc-camera and a classroom with good acoustics over anything else. 

Mindy Blue
Mindy Blue

How do you make sure that students at all income levels can access the lectures and educational resources via high speed internet?  Some rural communities don't even have libraries, or good internet at their libraries.

ahouseofintellect
ahouseofintellect

At the college level, students are supposed to write notes (rather than rely on "recall"), prepare questions, and make their own disciplinary connections while listening to a lecture. If they drift, it means they've put down their pencils, i.e., they've quit working. As far as collaboration events, those are called "labs," and colleges have long noted their usefulness.

msheriff
msheriff

Another question I have regarding the recall experiment...

Most lectures are constructed in a manner where the simplistic/ basest tenets of the topic are discussed first and then built upon over the progression of the lecture. Perhaps recall is limited to the simplest facts because a student's capacity for learning ITSELF is compromised (and not just their ability to remember things) and he/ she cannot understand the subject and, subsequently, recall it because it appears as a bunch of Greek to them.

This would be an interesting (and easy) study.

justathought123
justathought123

It seems that you could use this "model" in a religious setting as well.

ABig10Prof
ABig10Prof

My experience mirrors that of Nathaniel Campbell - the 50-minute lecture by the "sage on the stage" is no longer the norm.  However, neither are most classes at the ideal end of the teaching/learning spectrum that Mr. Kahn envisions.  Most classes exist somewhere in between, with faculty doing the best they can to be innovative  and to wisely incorporate technology.  Sadly, as with many teaching related issues, the culprit is resources, not faculty interest or desire.  Preparing and delivering the out-of-class materials that will form the basis of the in-class  discussions and activities requires significant time, effort and often expense.  For most classes, it is not simply a matter of posting a reading list or the lecture notes.  This is particularly true for highly quantitative courses.  Class size is another impediment.  My options in a class of 20 students are vastly different from those in a class of 100.  Hiring more faculty is apparently not an option; turning away 80% of the students clearly is not. 

Nathaniel M. Campbell
Nathaniel M. Campbell

It seems to me the author of this article hasn't been in a college classroom lately.  I teach the gen-ed freshmen survey courses in history and the humanities -- the supposed bastion of the 50-minute lecture.  I can count on one hand the number of times in the course of a semester that I actually spend most of each 50-minute class period "lecturing".  Even in a freshmen classroom, much of our material is covered in this "humanities seminar" format, with me asking questions and guiding the students through the primary source readings that they were supposed to have read ahead of time (emphasis there on "supposed to").  Even on days when we're not discussing primary source readings, my "lecture" is broken up every few minutes with questions to the students that prompt them to think about what I'm saying and push us forward to the next chunk of information.

In other words, the advice this author gives is excellent -- and is already being put to use in college classrooms.

BuckChuck
BuckChuck

@kristadg Ok well how then?

mrunge340
mrunge340

@John Golden How do you figure he's perpetuating "unhelpful math ideas" and "unhelpful teaching ideas"?

JJAtkins3rd
JJAtkins3rd

Khan actually does write about structured personal interaction and advocates small lecture followed by an interactive segment. You should read the entire article.

I hope this comment doesn't get deleted again as my point is valid, even if you are a paid commenter.

crack_stein
crack_stein

@Cammie Byerley This is the biggest problem in the world today. People just don't get who they're talking to. If you're speaking with a child, go down to their level and speak in a way that they actually understand. 

JJAtkins3rd
JJAtkins3rd

Your first problem is that you are applying Ph.D level physics and math to middle school and high school level math. Ph.D level math is more advanced than what he teaches online considering he created these videos to help his little sister.

Your second problem is that his work is supplementary to education, it was not meant to replace the student's education.

Your third problem is that you are discouraging readers from even trying Khan's supplementary material. There are teachers who use this material to go along with the students studies. You could be contributing to his free online teaching paradigm instead of blasting his methods. You could submit extra materials to his site and help out where you think is lacking instead of posting and deterring people from trying other avenues.

Lastly I hope my comment doesn't get deleted again, as I do have a valid point even if you are a paid commenter.

JJAtkins3rd
JJAtkins3rd

 Well, your first problem is that you took a random subject in a field you specialize in at the Ph.D level and applied it to high school math. Ph.D level physics for slopes is not the same as middle school/high school level mathematics.

Your second problem is that you are assuming that Khan is used as a primary form of teaching. His site and teachings are meant to supplement the eduction they currently receiving.

Your third problem is that you are critiquing him on this forum instead of contributing to his free world wide teaching site. You could be contributing videos or discussion material but instead you are deterring people who may want to learn or may actually benefit from his material.

JJAtkins3rd
JJAtkins3rd

 He does suggest interactive activity you should have read the entire article you need to improve your reading comprehension skills.

Paul Dawkins
Paul Dawkins

Where does the article mention college or university? You assume based on the word "lecture" that the article is focussed at the post-secondary level when students receive lectures in K-12 school at a surprising frequency. 

Brown_Dog
Brown_Dog

 Two more words: Uri Treisman.

msheriff
msheriff

Not all universities follow this same format. I am a graduate student and all of my classes are centred around discussions and student presentations of material, which is a fantastic way to encourage student learning. However, a LOT of classes are still based on the direct lecture format. Little technological innovations such as the I-clicker (where the entire class can be quizzed anonymously in real time) have been added, but when you have a class with four hundred students in it it's impossible to actively engage each person one-on-one without a passive lecture.

I agree that passive lecturing alone doesn't work, which is why I'm a big fan of the tutorial model that my university (and others) features. But the impracticality of large lecture halls is the limiting step in student engagement. I LOVE the idea of large lecture halls with multiple professors leading smaller student discussions, and this is an idea that deserves more thorough investigation.

Brown_Dog
Brown_Dog

What we can know from the article is that the actual researchers had already been questioning the merits and shortcomings of lectures in 1996, long before Kahn seems to have published anything about the topic, and they had been contributing to advance this research for several years.

 I am not a "paid commenter," but from your defensiveness here it appears that you may be.  Instead, I am an admirer of the concept that seems inherent with the Khan Academy. However, an article that comes up short on contextual reasoning, employs fallacies, fabrications, and fails to give credit where credit is due doesn't support the concept or advance the cause in a good way.

Hundreds of scholars have investigated and confirmed the merits of

active learning. It is their work that allows people like Khan to

stand on their shoulders and make such affirmations today . It is juvenile to bolster the value of an author's own perspectives by trying to deprecate others' perspectives as inferior. In this case, the 1996 perspective was particularly ill chosen to serve for this purpose. 

It certainly is a gaff  to characterize 1996 the work of Middendorf and Kalish as shortsighted and for the journalists (or Khan) to print speculations about what Middendorf or Kalish "did not question" in 1996 without talking to them and including actual quotes from them. National Teaching and Learning Forum, the journal cited, is a cut above that kind of journalism,. Readers who want real understanding of how thinking about university education has evolved should consider reading that instead of generalist magazines.

Geoff
Geoff

You're right—it doesn't.  But mentioning a class size of 300 means university is implicit.  Also, the author mentioned little actual interaction, which also implies university (arguably over secondary school and definitely compared to elementary school).  Finally, despite your argument to the contrary, use of the word "lecture" incites thoughts of university, not school.

To me, at least, the image created a disconnect that persisted as I read the article.  But you're right: University was not explicitly stated.

Nathaniel M. Campbell
Nathaniel M. Campbell

I agree with you completely -- I'm only able to teach the way I do because I am blessed to have gen-ed freshmen sections capped at 30 students.  When you get much higher than that, it becomes difficult to impossible to sustain any productive in-class interaction between professor and students.  Discussion sections are designed to make up for that, but not every big lecture class gets to have those (mainly because they are dependent on grad students to lead them).

JJAtkins3rd
JJAtkins3rd

 Im not a paid commenter I only believed you were because my comment was deleted.

ShuanJBistra
ShuanJBistra

@Geoff 

University is not mentioned, but college is.