Ranked lists are a mainstay of digital content publishing and can be found on most sites---from independent blogs to global media sites. For years, content publishers and online marketers have used ranked lists to drive traffic to their websites. Lists are highly shareable via social media, and other blogs and websites frequently write about and link to lists in their own content. All of those shares and incoming links not only drive traffic to the original list on the publisher's site, but they also increase the authority of the publisher's site, which can increase its rankings in Google search results.Long story short, lists get page views that publishers need to generate advertising revenue. But why are lists so popular? Sites like BuzzFeed have achieved great success constantly publishing "listicles" that rank anything and everything. The quality of the lists varies as much as the topics, but people continue to share them, read them, and link to them. Research published in the Journal of Consumer Research, The Top-Ten Effect: Consumers' Subjective Categorization of Ranked Lists, sheds some light on why lists are so popular. According to the scientific research data, "The top-ten effect that we demonstrate in these studies is based on the mental tendencies to use categories and to exaggerate the differences between them. These tendencies are part of the natural human readiness to perceive the world in terms of discrete things."The study authors provide recommendations for marketers to help them improve results, and those recommendations can be applied to content publishers, too. Specifically, publishers should leverage this innate human behavior, research the audience's "categories", and create content that speaks to the audience in those terms.The study also found that by categorizing, audiences also "chunk" information. It can be assumed that chunking enables them to better digest content in smaller pieces. According to the research, the human brain can more easily chunk numerical lists that end in zero such as 10, 20, or 30. For example, human beings chunk a list of 20 into the first 10 and second 10.In other words, audiences typically feel more comfortable with lists of 10 or 20 items than 7, 11, 19, or any other number in between. If they feel more comfortable subconsciously, they're more likely to read, share, and link to the content.You can follow the link at the top of this article for all of the details from the study. Keep these findings in mind next time you publish a listicle.