Add this to your teacher files of Things You Already Knew But Now Some Researcher Provided Proof.
The paper is entitled Do Motivated Classmates Matter for Educational Success? The answer is, of course, yes.
Every class has its own chemistry, and a major element of that chemistry is how much individual students do (or do not) care. Every single teacher can tell you the stories.
The classes you've had where everyone excels because a handful of students in the class are intense and achievement oriented. The class you've had in which students looked around the room and clearly thought, "Well, nobody else is knocking themselves out, so I guess I'm doing plenty enough."
In high school, in particular, many students are focused on one big question-- "How normal am I?" They find their answer by looking at their peers. "Peer pressure" is often portrayed as some kid making pitches like, "C'mon, smoke some donuts. Everyone is doing it. You don't want people to think you're a loser, do you?" But it's often way more subtle than that. Nobody has to explicitly make the pitch; teens are already checking to see what everyone else is doing. That's why major social currency in high school is not a col car or nice clothes or playing the right sport, but confidence-- projecting the air that you are NOT checking around you to figure out if you're okay or not. (Note: this is not the same as deliberately and even angrily rejecting what you thin k everyone else is doing.)
It's also a matter of setting an example. In high school, I learned a lot about playing trombone from John Stuck, who was not my band director, but the guy in the section a year ahead of me. He was good, and I picked up a lot just by listening and watching. By my junior year, one of my proud achievements was making "additions" to the music that got John in trouble. If John had not been in my school, or if either of us had been born a little sooner or later, I would have turned out different as a player.
I've seen versions of that play out many times. The student who was really lifted up because she happened to be in the same class as some high achievers. The top student who would have disappeared into the medium-level crowd if she had been a year older or younger. The class that always upped its game when a certain student was absent.
Sometimes a teacher can help amplify peer effects, and sometimes those effects are beyond their control. But there's no question that the peer effects matter. Now there's a piece of research to back up what teachers already know.
I noticed that the abstract says that the peer effect is not present in elementary classes. That’s perhaps true, but there IS something.
FWIW…After four decades of elementary teaching my guess is that it’s a combination of 1) teacher personality and 2) student behavior. Engaged, friendly, nurturing, and safe Elementary teachers motivate their students who, in turn, work hard to please this important adult in their lives. If a class has one or more serious behavior issues, however, the teacher can become exhausted, frustrated, and discouraged which reduces the motivational aspect of their teaching.
This is all guesswork on my part…based on the anecdotal evidence of my own career. I know that I did better some years than others…and it wasn’t always due to the makeup of the class. On the other hand, constant behavior issues took a lot out of me so that I struggled to stay positive.
When I taught a world language, teachers from all over the county held a World Language Adventure Day. Our middle school would take 6-8 language nerds every year, until one year a group of 3-4 very popular girls who were really enjoying their language classes decided to go. We ended up taking about 35 kids that year. For the rest of that spring, world language became the “in” class and kids did markedly better in class.