I was just reminded of an article in The New Yorker that I read a long time ago, in June 2006. The article, written by eminent neurologist Oliver Sacks, describes the experience of an adult woman, Susan R. Barry, a professor of neurobiology herself, who had been stereoblind her entire life, and suddenly regained stereoscopic vision after intensive visual training at the age of 48. While the full original article, titled “Stereo Sue,” is behind the New Yorker’s pay wall, I just found an awesome YouTube video of a joint interview with Drs. Barry and Sacks:
Completely ignoring the fact that Dr. Barry’s experience challenged long-held notions about the (lack of) plasticity of the adult brain, this, for me, is the most important piece of wisdom taken from the article (and the video): as a neurobiologist, Dr. Barry knew that stereo vision exists in others, knew exactly how it works and how it is processed in the brain’s visual cortex, and therefore concluded that she wasn’t missing anything important. After all, she had lots of other, monoscopic, depth cues at her disposal to estimate her spatial relationship to the world around her. And here’s the kicker: she was wrong. I won’t spoil it by paraphrasing; you have to hear and see her describe it herself, starting at 2:39 in the video.
Why does this article, and especially the video, make me so giddy? Because it mirrors how many people, specifically scientists, react when they encounter a “proper” stereo display, i.e., a holographic display, for the first time. They might have been working with a particular 3D data set for years, and might have been visualizing it from all angles and viewpoints using “3D” software for just as long, and think they know exactly where everything is and how it relates spatially to everything else, but the moment they see it holographically, they realize they didn’t. Which sort of challenges long-held notions about the (lack of) value of VR.
She couldn’t even experience depth in “wiggle 3d” stereo pictures other stereokinetic optical illusions?
“Wiggle 3D” is based on motion parallax, a monoscopic depth cue. According to the article, she was very adept at using motion parallax to get around, so I’m assuming that she was able to get depth information from those illusions.
But according to her, that’s no substitute for the “real thing.” The way she describes it, and the reason why I love the video so much, it’s like the difference between being told what it feels like getting punched in the gut, and getting punched in the gut.
There is a difference between consciously deducing depth and having things suddenly pop out of/into the screen. Personally i find it hard to distinguish true depth from the depth perceived when my brain gets into the zone after staring at a good wiggle/swaying 3D picture for a little while (at least until something causes a conflict in the perception and reminds my brain to extract depth cues from the differences between what each eye sees); though perhaps i’m just a freak…