The Dress Debate
Image: This picture inspired endless debate: is the dress white and gold or black and blue? Image from The Independent.
As an experiment, ask someone to take a look at the image of the dress above and tell you what colors they see. Even when viewed on the same computer screen, two people can see very different dress colors. Understanding that the differences in perception are biologically mediated allows us to look for deeper explanations as to why and how our perception differ. For instance, one explanation for the dress debacle is in the way our brains evolved to use the hue of the sky to estimate the time of day (warmer tones indicate morning and evening, while cooler tones dominate midday and dusk/dawn) and our psychological preference for warmer and cooler lighting (Lafer-Sousa et al., 2015).
The Ishihara Test for color blindness involves identifying numbers and patterns in images designed to contrast in trichromatic vision, but not dichromatic vision. Typical dichromats perceive the circles in at least one of the images above as uniform in color and cannot see the number within. Use the slider to compare typical vision to color-blind vision. You can take an online version of the Ishihara Test here.
Use the slider above to see the rack of clothes as someone with red-green blind dichromatism.
Taking a step further...
Taking yet another Proustian step, try imaging the world without sight at all.
Erik Weihenmayer lost his sight as teenager, yet as an adult, he became the first and only blind person to climb the tallest mountain on every continent (including Mt. Everest) and paddled his own kayak the length of the Grand Canyon. During these adventures, he ‘saw’ the world in a very real way. In the absence of visual input, the signal from other senses can co-opt the visual cortex, allowing blind folks to ‘see’ the world in sound and touch (Gori et al., 2017). As Weihenmayer put it in an interview, “I’m listening to things, I’m touching things. And that’s actually… creating pictures in my brain... I am envisioning it in my brain.”
It is probably difficult for any of us to truly imagine ourselves on the icy flank of Mt. Everest or the riotous white-water of the Grand Canyon with our own senses. It is almost impossible to imagine ‘seeing’ these worlds as Weihenmayer does, without any visual perception at all.
Perception is a complex and highly integrated process, and unfortunately, we have no means to swap ourselves into another’s brain. So, we are stuck using inference to imagine the world through other eyes. As we take more steps along the Proustian pathway into visual systems increasingly more dissimilar from our own, our ability to infer similarity begins to break down. In the same way, our ability to comprehend the quality of vision in other organisms wanes as we move farther away from the human eye in the tree of life, from gorilla, to deer, to frogs, to fish (for instance, it is impossible to comprehend the world of deepsea Cyema that see, not light waves, but electric fields and pressure waves (Meyer-Rochow, 1978)!).
Like Proust proclaimed, imagining the world through the eyes of other people opens up the beauty, diversity, and enchantment of other worlds; but, seeing the natural world through other eyes of other living creatures can open up a richer understanding of ecology and evolutionary history.
In this project, we will take a Proustian stroll to see the same forest through the eyes of a few of its animal inhabitants: deer, hawk, sparrow, frog, and fish. In doing so, we will gain a fuller understanding of those animals and how their vision relates to their ecological role.