You may not know the term "parallax scrolling," but you've probably seen it in action. In the past couple years, parallax has become perhaps the most popular site design tool out there, embraced by commercial products and (largely thanks to "Snow Fall" from the New York Times) mainstream media alike. The effect occurs when various page elements move at different speeds, creating a sense of animation and a heightened interactive experience (examples below). It's a step away from pragmatism and functionality toward novelty and visual appeal.
Whether that step takes web design in the right or wrong direction has become a topic of considerable debate. The parallax style has excited web developers and inspired any number of hype lists. It's also triggered a backlash among critics who feel its bells-and-whistles approach detracts from actual content. Pitchfork creative director Michael Renaud recently told the Atlantic Wire he expects people to "tire" of the trend within a year or two.
What the discussion has lacked so far is much evidence from web users themselves. That's the first thing Dede Frederick noticed when he decided to study parallax scrolling for a graduate project at Purdue University. Frederick, who's currently getting a doctorate in web design, scoured the literature for studies of parallax—and found none. "It looks nice, and I like it," says Frederick of parallax, "but I couldn't find much [research] to start me off."
So Frederick set up a study of his own. He designed two hotel websites similar in every way, from content to color scheme, except that one featured parallax scrolling and one did not. Frederick then intercepted 86 people in the lobby of the Stewart Center, a main gathering point on Purdue's campus, and brought them to a computer where they engaged with either the standard site or the parallax site (screenshot below).
The test itself didn't last very long. Participants spent a few minutes getting familiar with whichever site they'd been assigned. They entered demographic information into a web form. (They all experienced a site error, too, because Frederick wanted to incorporate the unruly nature of web use.) They made a hotel reservation. Finally they rated the site on a questionnaire crafted from prior web research.
Frederick's survey focused on five areas of the user experience: usability, enjoyment, fun, satisfaction, and visual appeal. (Enjoyment and fun, while ostensibly similar metrics, differed in that a site like IMDb can be enjoyable without being fun in the way a video game site might be.) Before he tallied the results, Frederick was convinced the parallax site would blow its opponent away.
"I've read from many blogs how people say it's going to attract users and create so much of a better user experience," Frederick tells Co.Design. "I thought it was going to be superior to a typical website in every aspect."
As it happens, the parallax site was only superior in one sense—fun. None of the other survey measures indicated a significant difference in user experience between the two sites. Parallax didn't even edge the standard site in questions about visual appeal (although participants did think it looked slightly more "professional"). Frederick also discovered one critical disadvantage of parallax: test participants who suffered from motion sickness found the style disorienting.
The results left Frederick at a bit of a loss to explain the perception of superiority that surrounds parallax design. "I guess, just like me before my research, they're going from what they see," he says. (Frederick plans to submit his research to a journal for publication soon.) One reason he may have found virtually no difference in user experience between the sites is that the standard site he created was also very pleasant. Then again, if parallax were truly a game-changing tool, it should be able to elevate a site from good to great.
Future tests might go beyond the general experience of users to consider the ways they engage with a parallax site. Eye-tracking research, for instance, could help designers recognize which elements appeal to readers and which merely distract them. Content-related questions, rather than general surveys, might let researchers determine whether parallax interferes with a user's ability to process the story the design is supposed to enhance.
Sobering as this first careful study of parallax might be to web designers, Frederick still believes it's a fad with a future. He cautions developers to think more carefully about the context in which parallax is applied. Text-heavy sites that employ parallax scrolling seem more likely to disorient users, he says. Sites that emphasize visual elements—images, infographics, or data visualizations, in particular—are probably a better fit for the style.
"Right now, people have not understood much about parallax scrolling, and they're using it in all different contexts," says Frederick. "So I think, for example, in a content-based website, you're probably going to see less of it, and it's going to move to the more suitable context."
Image courtesy of Dede Frederick