He Jiang: Studying the “spillover effect” and the unintentional spread of information in a classroom

This photo shows the head and shoulders of a young Asian woman with dark hair pulled back and wearing a gray hooded sweatshirt. She is smiling at the camera. The background seems to be the cream-colored wall of a room. — Virginia Tech Department of Economics graduate student He Jiang studies unintentional flows of information. Photo courtesy of He Jiang.

The following story was written in November 2021 by Benjamin Sammons in ENGL 4824: Science Writing as part of a collaboration between the English department and the Center for Communicating Science.

Have you ever noticed how information like gossip and rumors can spread quickly throughout a population? What about things like trends, life hacks, or news? Sometimes it can seem like you tell a single person something interesting and within a few hours everyone knows what you said.

That principle can be applied to things like knowledge in the classroom and parental influence. What effect does outside influence have on education, and does that information spread to other students in the same class? That is exactly what He Jiang, a fifth year PhD student in the Department of Economics, is studying right now.

A few years ago, Jiang was working in the sales and marketing department at an insurance company and quickly caught on to an odd phenomenon. The company paid for marketing and advertisements in specific spots or areas. Yet people from other areas still knew about the company, despite never having seen any of the marketing. When a company pays for advertisements in a certain area, and the information they advertise spreads to another area by word of mouth, it is called marketing spread. But Jiang saw potential for this effect to be in more arenas than just marketing and began researching into a much larger and broader version of this phenomenon, called the “spillover effect.” The spillover effect is what happens when one person or group invests money into learning something or building something, and the benefit or consequence of that investment is unintentionally spread to other people close by.

An easy way to describe the spillover effect is by examining some specific data that Jiang decided to focus on in her research, the impact of this effect in education. Take, for example, a traditional classroom full of students. One of those students has parents who pay for extra tutoring outside of class. When that student comes back to the class after tutoring, and uses the information they learned, that information can spread to other students in the class, even though they didn’t pay for or attend the after-school tutoring. That’s essentially what the spillover effect is, the unintentional spread, benefit, or consequence of something that someone else has purchased.

This photo shows a young woman holding the skull of a cow. Four or five young children are looking on as she talks about the skull. They seem to be in a classroom. — If one of these children already knows something about skulls, what effect does this knowledge have on classroom learning for the other children? He Jiang studies this "spillover effect." Photo courtesy of Caitlin Colleary.

Jiang studies the spillover effect by creating theoretical models, which are guesses on how the spillover effect will happen in a specific situation, and comparing them against data collected from classrooms in China. For example, she might make a prediction about the effects of some students having extra tutoring and then compare that prediction to data collected in an actual classroom. Jiang then revises her prediction through trial and error until she makes a model that matches what actually happens.

Using this research, Jiang can draw conclusions that greatly benefit several disciplines and aid our understanding of how external factors can affect education. For her current research, Jiang has focused on how factors like after-school tutoring and parental influence can spill over to other students and how this affects the students’ performance in school. Jiang also studies whether the spillover effect is more prominent in verbal versus computational classes or in different subjects. Using this research, Jiang can determine the true benefits of these factors and how to use the spillover effect to our advantage and improve the educational experience for all students.

Jiang’s research has focused largely on education thus far, but it has great potential for studying this effect in other areas of life and through different lenses. In the future, Jiang plans to move to studying non-cognitive skills, which are more abstract than traditional academic skills. For example, might having one set of parents who are not divorced cause a spillover effect to that child’s class and lower something like anxiety or depression or provide lifelong beneficial skills? Essentially, Jiang would be testing for things that cannot be traditionally measured in school.

She also wants to examine factors like birth order, whether younger or older siblings are more susceptible to the spillover effect, and gender, whether a specific gender is more likely to have the spillover effect. Jiang will also study things like long-term benefits of the spillover effect. For example, will tutoring that spills over to other students cause a long-term increase in their grades, or will their grades fall again if the spillover effect is removed? The potential avenues for new research on the spillover effect topic make it viable for years to come.

By studying the spillover effect, Jiang aims to help people worldwide understand how the factors around them influence they ways in which they learn and interact with their peers. The spillover effect can be used to help students learn better. It increases the benefits of an investment in education because that investment will reach more people than originally intended.