Appearances, vision and our perception of the world


April 1, 2015


IN a casual discussion inside my research lab one afternoon, I posed this question to my staff and students: what is the connection between the Mamasapano debacle and the color of the cocktail dress that was originally posted in Tumblr? There was a bit of discussion between them before I gave an answer. I will share that thought with our readers at the end of this column.

The speed at which the news of a “mysterious” color-changing dress spread was facilitated by the same natural phenomenon that caused the story in the first place. The Internet is a collection of servers that is interconnected by fast fiber optic cables that transport flashes of light that contains the text, images and multimedia that we all consume in our web browsers, smartphones and other devices.

Despite this ubiquitous nature, light and light phenomena are still not easy to understand. It may be because we do not really have a course in elementary or secondary school where we are taught the whole of optics. Optics is the formal branch of science that studies light and other light related phenomena.

Most of our formal understanding of optics in the earlier stages of schooling is usually limited to color and sometimes with vision. A deeper understanding between the interrelation of light, color and vision has to wait until a formal course in electromagnetism which–for many—is already a bit too advanced for their degrees.

Even in a typical undergraduate optics class, we encounter many misconceptions with regard to light which become a source of confusion among students and those who teach optics as well. These misconceptions range from obscure terminology, misleading diagrams, teacher-induced confusion to conceptual gaps.

Obscure terminology arises from the fact that, historically, many optical terms were taken from a variety of sources by Greek, Arabic, Dutch, French, Latin and English authors. With the development of language, additional connotations get to be attached to a word which may have a specific meaning when used in optics.

Confusion may arise in the formal technical use of a word that is laden with other meaning and experience. The converse is also true when one invents a word that has no connection to the actual optical phenomena.

We can partly trace the difficulty to the fact that the fundamental phenomena associated with light occurs in scales far removed from the range of human experience. Light is quantized in energies that are a millionth millionth millonth millionth (that’s four of the millionths there) smaller than the energy contained in a single grain of cooked white rice. On the other end of the scale, stars, like our sun, is 10,000 to 100,000 million times larger than a human eyeball. This disparity in scale of experience to the scale of light phenomenon sometimes makes these concepts resist simplification. More often than not, it requires novice learners to accept explanations that run counter to their “normal” macroscopic perception of the world.

The dominance of vision-related optics terms point to the importance of the eye and vision as our primary interface with light phenomenon. We “see” things even though at the basic level vision is when we detect energy through our retinal cells that are eventually processed by our brain. When we start discussing quantum and wave phenomena, they become “add-ons” to how we learned to process what we see. Even how we “see” color can be a source of misconceptions, as the perception of the color of that dress have shown us.

I have a student who is color-blind and whose ability to see red and green is different. His experience gives us an insight on how we perceive colors since despite his inability to “see green”, he can—most of the time—say with confidence that the leaves of trees and grass are green. He “knows” of the position of the green light in pedestrian crossings and in traffic signals. In other words, his concept of “green” is a learned experience.

The confusion on the black and blue dress is a reflection on how we usually misunderstand vision. The color of what we see (or what a camera detects) depends on three things: the colors of the light that illuminates the object, what the object absorbs (or reflects), and the sensitivity of the camera to different colors. Having the same object under different light conditions can account for the different “color” perception. Conversely, the same object under the same light but with a different camera can also result in a different color.

In the end, perceptions are just that—primary sense information. These have to be processed and placed under context. The underlying reality can be discovered only when we study the interactions of the elements of the system under study and figure out what is behind their dynamics.

Just like the debacle in Maguindanao, things are not always what they seem. How we see things must be grounded in the interrelated phenomena, or for that matter, interests in the area. We must be careful since too dim an illumination will not yield any information on an object but too much light can wash out details for a camera that has a low threshold. This is similar to what is going on with the hearings for which I will borrow a non-optics name: whitewash.

Giovanni Tapang, Ph.D., National Chairperson of Agham.