Popular publications include things like magazines and newspapers. The articles in these publications are written by journalists or freelance writers. Although a journalist may be knowledgeable about the topic on which they are writing, they cannot be considered "expert" in the way that scholarly researchers are, and the articles they write are definitely not research-based.
In some cases, a popular article from a magazine or newspaper can take the results of research published in a scholarly article and make the research more approachable to the average person.
Here is an example of an article on an online news site that describes a research article published in a journal. (In this case, the popular article includes a link to the scholarly article.) It is important to remember that a popular article like this presents the journalist's understanding or interpretation of the research, so it would be in your best interest to examine the research article yourself.
