Every once in a while, someone claims that data visualization can be enhanced when viewed in virtual reality (e.g., by wearing a VR headset). Not once, however, has anyone demonstrated any real benefits. If you think about it for a moment, this isn’t surprising. How could viewing a chart in VR possibly work any better than viewing it on a flat screen? The chart would be the same and VR doesn’t alter visual perception; it merely gives us the ability to navigate through a virtual world. Whether viewing the real world (including a flat screen) or a virtual world, our eyes work the same. VR is useful for some applications, but apparently not for data visualization.

VR only gives us a different way of changing the perspective from which we view a chart if the chart is three dimensional. If the chart is two dimensional, whether viewing the chart on a flat screen in the real world or in the virtual world, we would view it straight on. Viewing it from any other perspective (e.g., from the side or behind) would always be less useful than straight on. If the chart is three dimensional, however, in addition to moving the chart around to view it from different perspectives as we would when using a flat screen (e.g., by rotating it), in VR we could also virtually move ourselves around the chart to change perspectives, such as by virtually walking around to view it from behind. Does this offer an advantage? It does not. What we see once we shift perspectives is the same, no matter how we get there.

VR does offer one other navigational possibility. While wearing a VR headset, we could virtually position ourselves within the chart, among the data. Imagine yourself in the midst of a 3-D scatter plot, with data points all around you. Would this offer a better view? Quite the opposite, actually. It would cause us to become metaphorically lost in the forest, among the trees. How much of the data could we see if we were located in the midst of it? Very little at any one time. To see it all, we would need to turn back and forth to see only bits of it at a time. Much of a chart’s power is derived from seeing all of the data at once. What might seem cool about VR navigation on the surface would be dysfunctional in actual practice when viewing data visualizations.

Before moving on, I should mention the general uselessness in all but rare cases of 3-D charts that encode a variable along the Z axis. The Z axis simulates depth perception, but unlike 2-D positions along the X axis (horizontal positions) and the Y axis (vertical positions), which human visual perception handles exceptionally well, our perception of depth is relatively poor. It is for this reason that vision scientists sometimes refer to human visual perception as 2.5 dimensional rather than 3 dimensional. 3-D charts suffer from many problems, which is why the best data visualization products avoid them altogether. Viewing 3-D charts in VR solves none of these problems.

I was prompted to write about this in response to a recent press release about a new product named Immersion Analytics by the company Virtual Cove. The company claims to provide several patents-pending features that enhance data visualization through VR. When I read the press release, being the suspicious guy that I am, I suspected yet another false claim about the benefits of VR, but I was more than willing to take a look. What I found, as expected, was pure nonsense. I’ve examined every example of an Immersion Analytics data visualization that I could find and observed nothing that would work any better when viewed in VR rather than on a flat screen. During a promotional presentation that’s available on YouTube, the company’s founder, Bob Levy, who “invented” the product, listed three visual attributes, as examples, that we can supposedly view more effectively in VR: Z position, glow, and translucency. I’ve already explained how Z position is just as useless in VR as it is on a flat screen, but what about the other two attributes? By glow, Levy is referring to a halo effect around an object (e.g., around a bubble in a 3-D bubble plot) that varies in brightness. You can see this effect in the example below.

Notice how poorly this effect works as a means of encoding quantitative values. Can you determine any of the values? I certainly can’t. Nor can we compare halo intensities to a useful degree. How could this possibly work any better in VR? VR doesn’t enhance visual perception. Our eyes work the same whether we view a chart on a flat screen or in VR. The remaining attribute—translucency—is no different. What Levy means by translucency (a.k.a., transparency) is the ability to see through an object, like looking through glass. Varying the degree to which something is translucent is also illustrated in the example above: the bubbles are translucent to varying degrees. Can we decode the values represented by their translucency? We cannot. Can we compare the varying degrees to which bubbles are translucent? Not well enough for data sensemaking. During the presentation, Levy claimed that if we could view this chart while wearing a VR headset rather than on a flat screen, translucency would work much better. That is a false claim. Our perception of translucency would not be changed by VR, and it certainly wouldn’t be enhanced.

Based on the examples that I reviewed, my suspicions about the product’s claims seemed justified. When I contacted Andrew Shepherd, Virtual Cove’s VP of Strategic Growth who functions as their media contact, to ask several questions about the product, I honestly admitted my skepticism about their claims. In response, he wrote, “I know it could be a long shot, but it would be a thrill to convert you from a skeptic into a true believer.” Definitely a long shot, but I nevertheless offered to examine the product in VR if they would loan me the necessary equipment. Perhaps you won’t be surprised to hear that they don’t have any VR headsets available to loan to skeptics. Faced with no possible way to evaluate their VR claims directly, I asked Shepherd a simple question: “What can be seen in VR that cannot be seen just as well on a flat screen of equal resolution?” I’m still waiting for an answer. I’ve found that Shepherd quickly responds to questions that he likes, but persistently ignores those that are inconvenient. I am still quite willing to be surprised by VR-enhanced capabilities that contradict everything I know about visual perception, but I’m not holding my breath.

If a vendor tries to sell you VR data visualization software, I suggest that you either ignore them altogether or do what I’ve done—ask them to justify their claims with clear explanations and actual evidence—then be prepared to wait a very long time.