For this assignment I choose the size constancy from the sensation and perception tutorials. Size constancy refers to the fact that our perceptions of the size of objects are relatively constant despite the fact that the size of objects on the retina vary greatly with distance. In the experiment a photograph of several people walking on a hiking trail that extended to a perceived horizon led to the sensation of depth and distance and although the actual pixel size of the people farthest away was smaller my perception was that all of the people were relatively the same.
In the next image one of the people farther away was copied and pasted next to a person closest in the photo giving the sensation that the copied person was very small which represented a variation of a classic demonstration of the power of size constancy done by Boring (1964) this distorted sensory illusion caused confusion while my mind tried to processes the foreground and background and the perceived horizon which leads to the conclusion that the process between the eye and the mind is affected by the surrounding sensory information, in a since the mind creates a scale by which to judge size.
This experiment reminds me of a similar illusion that my father taught me as a child in which the end result is a photo of someone holding their hand out palm up hold another person that appears to be only a few inches high. The illusion is created by having the first person with their palm up stand close to the photographer and the second person stand ten or so yards away in the background, yet one of the real keys to the illusion is that both people are standing in a wide open area such as a farm field so there are no surrounding sensory information by which the viewer can judge the size of either people in the photo.
For example having a house or car in the background would change the viewer’s perception and the illusion would not work. I believe this example confirms the power of size constancy in our sensation and perception. References Baron, R. A. , & Kalsher, M. J. (2008). PSY105: Introduction to psychology: Third custom edition (3nd ed. ). Boston, MA: Allyn & Bacon (Pearson). Boring, E. G. (1964). Size constancy in a picture. American Journal of Psychology, 77, 494-498.