Diffusion Effect in Health Studies When health education experts want to test the effectiveness of a program designed to improve a particular health condition, they often do a study with two groups of people. One group participates in the program, while the other does not, and the researchers compare the two groups to see if the program was effective in improving health. However, if the groups come into contact during the study, a diffusion effect may occur. Members of the group participating in the program may mistakenly share information about it with members of the other group. This often leads to the results of the study being useless.
Narrator: Now, listen to part of a lecture on this topic in a psychology class.
So, OK，let's look at an example. A researcher wanted to study ways to prevent office workers from getting stiff and tired sitting all day at their desks. So he came up with a simple program of exercises, special stretches, and things. And he wanted to know if this exercise program would keep people from getting so tired during the work day. So he did a study. He divided the workers in an office building into two groups, group A and group B. The researcher had group A do this new exercise program, these special exercises and stretches everyday while group B they were told just to work as usual and group A was told not to tell group B about the exercises they were doing.
The study went on for a couple of weeks. And what happened was one day some people from group A were talking about how the exercises they were doing were making them feel great that they weren’t becoming so stiff and tired during the work day. And some people from group B were sitting nearby and overheard them. So these people in group B decided to start doing the exercises too. So of course, the researcher wasn’t able to tell how well the exercise is actually worked, because people from both groups were doing them.
Explain how the example from the lecture illustrates the concept of a diffusion effect.
The reading talks about the diffusion effect which means when health experts are conducting programs, the results can be ruined by people who participate in it mistakenly sharing information with others who are not involved. In the listening, the professor uses research in a company as an example. A researcher wanted to find out ways of preventing workers from being stiff and tired all day. He divided the workers in a company into two groups. People in Group A would do some exercises as he said while people in Group B just worked as usual. The key point was that people in group B didn't know who was going on. But a few weeks later, people from Group B overheard that people in Group A actually felt really good after doing the exercises. So they started to imitate. And finally, as we can guess, the researcher could tell nothing from the research.
