Things Every Designer Needs to Know About People: Peripheral Vision Determines where Central Vision Should Look
It’s 11:00 a.m. on a Saturday and you’re at home in front of your laptop, browsing the Internet. You open your favorite news site and scan the headlines. You click on a story and read for a bit, then go back to the main page and scan some more. You choose another story, look at the picture, and read some more—just normal scanning and reading online behavior, right?
What you may not realize as you do this is that your two types of vision, central and peripheral, are multitasking.
But Isn’t Multitasking a Myth?
If you’ve read any of my other books or blog posts, you know that I’m fond of saying that multitasking doesn’t exist; most of the time what people think of as multitasking is actually fast “task switching.” People switch really quickly from one thing to another, from one focus to another. This quick task switching takes a toll on attention and mental processing.
But central and peripheral vision multitasking is different. People really are capable of multitasking when it comes to vision.
A Quick Definition of Central and Peripheral Vision
The fovea is a small depression at the back of the retina that affords very clear, detailed vision. Foveal vision, or central vision, covers only a very small area—about the size of two thumbnails—but it takes up half of the processing in the brain’s visual cortex.
The rest of the visual field is peripheral vision. Peripheral vision takes in a much broader and larger view. The visual cortex can process both central and peripheral vision at the same time.
Eyes Take Lots of Visual Samples at the Same Time
People take in visual information in little bites. This is called visual sampling. Central and peripheral vision are working at the same time. When you’re scanning that page online and a headline grabs your attention, you move your head and your gaze so that the headline is in view of your fovea—your central vision. But how do your head and eye know to look at that exact spot?
Peripheral Vision Calls the Shots
Casimir Ludwig, J. Rhys Davies, and Miguel Eckstein’s research (2014) showed that it is peripheral vision—what it sees, and how that information is processed in the brain—that tells the central vision where to focus next. This is a largely unconscious process. People are consciously aware of their central vision and what it’s processing, but they’re likely not consciously aware of what’s in their peripheral vision, or that their peripheral vision is calling the shots for where to look next.
Two Visions are Better Than One
You would think that all this multitasking would slow down visual processing, but Ludwig’s research shows that central and peripheral vision are processed independently to a large extent, and, therefore, both can be done quickly.
Don’t Base Every Design Decision on Eye-Tracking Studies
Most eye-tracking research measures only central vision; it doesn’t address what’s going on in peripheral vision. Yet there’s a tendency to make design decisions based on eye-tracking results (“No one looked at this picture, therefore it’s not effective and we should remove it.”). Now that you know that peripheral vision is calling the shots, you can avoid making decisions based solely on eye-tracking data.
Pay Attention to Peripheral Vision
Since peripheral vision directs where central vision should go, it’s important to pay attention to what people will see in their peripheral vision when they focus on certain parts of a page with their central vision. Peripheral vision isn’t just dead space to be left blank. As a designer, you need to design flexibly to allow for different monitor sizes and devices (large screen, laptop, tablet, smartphone). There’s a tendency to use only the middle part of the screen and leave the edges blank. This might be easiest for creating one screen that translates to multiple devices, but it means that you’re leaving peripheral vision with nothing to look at. Figure 4.1 shows a website for a restaurant that makes full use of peripheral vision to grab attention and help people know what the site is about.
FIGURE 4.1 A website that makes full use of peripheral vision.