Author Archives: Alexandra Cara Szerlip

Color Perception

A topic that I find really interesting is the idea of color. I have always just assumed that every physical object in this world obtains the colors we see. I have never really thought about the fact that color, including many other aspects of the world, is something that is actually psychophysical, and not just physical. The colors that we see are actually there because of the wavelengths of objects that are reflected by those colors. Surfaces have light reflected off of them differently. None of that technical stuff comes to mind when looking around in the world, because what we see just comes easy to us. Just like humans have brains that give them the ability to see the wavelengths of color, different animals have certain abilities that make them perceive the world differently. For example, bees can see ultraviolet light, which can attract them to the area of the flower where they need to pollinate. Fire flies can see through bioluminescence, and this feature helps them attract mates. They certainly do not see the colors humans see. This proves that in fact, what humans see, is not necessarily what is right, it is just what we perceive that helps us survive efficiently. Another really interesting aspect to color is how light and dark makes us perceive colors differently. When lights are shut off and you are looking at objects, we cannot see colors. Nothing has changed of the physical property of the object, or the wavelength that is being reflected. But, since we use rods in the dark, not cones, our rods only have one kind of photopigment molecule. Therefore, we can not differentiate between colors in the dark. It’s very interesting to me that even when sitting in the dark, the actual colors that we would see in the light are still present.

SaccadesMI

The topic of saccades really interests me because it is something I am constantly doing without necessarily noticing. Saccades are eye movements that can be both voluntary and involuntary, where the eyes rapidly change fixation from one object to another. This is the eyes ways of scanning the visual field. When reading, we make saccades to help bring the text into our fovea.If the print was not in our fixation, visual crowding would occur.  It is crazy to me that our eyes are doing saccades for about a quarter of a second and about seven to nine letter spaces, and yet we don’t notice anything going on in our eyes. When we read, it all feels so natural, but our eyes are in fact making constant movements. While information processing doesn’t occur during the saccades, it actually occurs during the fixations. I think it is really fascinating how the processing through our eyes occurs so fast that if a word only remained on a screen for fifty milliseconds after fixation first takes place, reading would be normal.  Saccades are also used when viewing any scene, and our place of fixation is not random. When looking at figure 8.17 in the textbook, of the little girl, I noticed that my eyes focused more on the areas of her eyes, and nose. This makes sense for most people, because we focus on more interesting places in an image. Our eyes respond more to contours as opposed to featureless parts.  When looking at images, our mind just tells our eyes to do certain things, move certain ways, and look at certain parts. All of our eye movements, especially saccades, are important in helping us view our world in every day life.

 

Wolfe, Jeremy M..Sensation & perception. Sunderland, Mass.: Sinauer Associates, 2006. Print