Seeing in Stereo and Other Thoughts

This weeks readings brought to mind an anecdote about an acquaintance of mine: after seeing a 3D movie in theaters (with much-improved technology since Tussauds’s “House of Wax”), he took off the glasses and said “I wish the world could be in 3D.” We all laughed at him, thinking that the world is, of course, already in 3D. But the joys of someone like Sue, who experiences stereopsis for the first time, very well did feel that longing for her vision to produce three dimensionality. And, of course, Sacks mentions how the process can go the opposite way, and how Paul Romano lost recognition of objects, as well of a sense of spatial orientation when he suffered an ocular hemorrhage in one eye.

Sacks’s own memoir of losing stereopsis after his stint in a recovery room was fascinating to me; we have all of course experienced changes in vision after reading for an extended period of time or starting at a computer screen, but to lose something as huge as stereoscopy (and related spatial judgement) after a fairly brief period of time (three weeks) was frightening, in a way. I shared Sacks’s wonder about prisoners and people living in dense rain forests who judged mountaintops as within arms length.

Her wonder and excitement at her new ability to see also paralleled my experience upon first getting glasses for my near-sightedness that had gone unnoticed until I was a sophomore in high school. When I put them on, I looked around, immediately noticing all the fine details of the world around me that I hadn’t questioned as blurry, like the edges of leaves that made up a green of a tree. I could so fully relate to Sue’s joy at finally seeing the levels of a three-dimensional world, just I rejoiced at being able to see crystal-clear details of things that were far away.

In terms of artwork, this creates another interesting paradox. Livingstone comments on the fact that finely detailed pieces of art provide a good stimulus for stereoscopic depth perception, and thus stereopsis provides a strong signal that the painting is flat, rather than three-dimensional. To remedy this effect, Leonardo da Vinci recommended closing one eye and standing a distance from the painting, to remove those cues and allow the viewer to see the monocular depth cues without interference from the “flatness” of the painting. (I grew up around artists and often saw this tactic used, but had little idea what it did until now!) The Conway and Livingstone article hypothesizes that artists, Rembrandt being an example, were more likely to be strabismic than non-artists, allowing them to use monocular depth cues to a greater extent.

Conversely, Livingstone writes in her book that paintings without fine detail, such as Impressionist works, do not invoke a strong signal from stereopsis to convey that the painting is flat. Other depth cues can then give the illusion of three-dimensionality. This effect can be exploited to a greater extent by the coarse dabs of paint that are present in many such paintings. The mismatch of these dabs between the two eyes can create a strong sense of three-dimensional volume which is filled with small floating objects (just as Sue eventually saw the noctiluca and the snow).

In line with Conway and Livingstone claim that Rembrandt and other artists may be strabismic or lack stereoscopic vision, I was really fascinated by the fact that children with autism had greater success with overcoming cognitive biases and drawing objects realistically. This section of the article reminded me of our conversation about the book Drawing on the Right Side of the Brain, which in effect works to overcome many of these cognitive biases by isolating aspects of the drawing, drawing upside down, etc. This allows children with autism to draw objects as they see them, without interjecting their knowledge about the three-dimensional shape of the object (this knowledge itself may not even be present or relevant to the child with autism). The authors go on to say that these drawings rarely have a single point perspective, and change perspectives based on consistency for a local region or object in the scene.

To finish my thoughts, here is a cute video from a movie I used to watch all the time as a child, The Thief and the Cobbler. While not wholly relevant to this week’s readings, it is certainly relevant to the concepts of three-dimensionality, and the reorganization of space based on interruptions of our assumptions. It’s quite short, and has an M.C. Escher-like quality to it.

Enjoy! Thief and the Cobbler Video