By: Rimsha Dar
Illusions are perception that does not relate to actual happenings or that is different from reality. When we see different things in our surrounding we take them as we look them but some of the things or objects are depicting entirely different picture. This may happen almost with every human because it is some kind of trick or error of brain. The fact about such illusions are not because of brain error or foolishness, in fact there is some flaw in decoding message by brain. There are different kinds of illusion which relate to other parts of body as well but the most important in them is optical illusion. Optical illusion:
Optical illusions are visual images that are different from realities. Our eyes see something and brain accept that information but it is not real which the eyes see. The brain makes some error in perceiving correct dimension of image. As study showed “when the differences occur between perception and images seen by eyes then it forms illusion. Actually, there are particular illusions which deceive the human visual system into perceiving something that is not present, or incorrectly perceiving what is present”. (Sarcone, Weaber, 1997, para.1).
As Wikipedia showed “Jastrow was interested in perception, especially in eyesight. He thought that eye sight was more complex than camera and that the mental processing of images was central to interpretation of the world. He believed that what people saw also depend on their emotional state and their surroundings”. (Joseph Jastrow, free encyclopedia, n.d)
One study showed that “Gestalt believed that people naturally seek out patterns in the sensory information available to them. The principles of grouping of gestalt are that human tendency to organize isolated stimuli into groups on the basis of five characteristics.
In this illusion arc A is looking smaller than arc B. In original both arcs are of same sizes and length .The arcs are identical and has no difference in reality. This is called Jastrow perceptual illusion which helps in perception of visual objects. As Jastrow mentioned in his theory that eye sight is more complex then camera so we can depict this phenomena through this illusion. When a person see this image first time then his brain deceives from his eyes. It’s because of lack attention and the surrounding that affect the stimulation of brain activity which stops perceiving the reality from an image. If we focus on the gap between the two arcs then we come to know that there is no difference. The areas that are associated to cortex part of the brain are responsible for visualizing images and take message from the sensory parts to the brain. (Ciccarelli, White, Fritzley, Harrigan, 2014, p.8). When we visualize an image it might happens that the information from the sensory input is not correctly interpreted. Due to which we get the wrong image of this picture of Jastrow. That is why it comes under illusion and when the sensory input just focus on the two arcs then they convey correct message to cortex areas and we get the right image of the picture. When we focus on images with full concentration then our sensory inputs take right message and that is why brain stimulate it in a correct way without making errors.
This a gestalt duck rabbit illusion. This image is like a figure ground illusion image because both are ambiguous or reversible images. Each time when we look on the picture it switches. When we look at once we can see duck and on the other time we can see rabbit. These type of images are famous for the multistable perceptions that is multiple but stable perceptions as shown by the studies (Ambiguous image, free encyclopedia, n.d). As we give first look to image our sensory inputs take an image as a single whole image rather than half or multi dimension. That is why brain get the picture of one animal easily but when we focus more, then brain might get the message that image has been switched. Here brain activity becomes slow and might make error for depicting exact image. Occipital area of brain interpret the message and visualize it as a single animal image. After looking again and again on the image our visual inputs start working faster to get the image of both animals but even then our sensory inputs will focus on one image properly rather than both images simultaneously. If this happen then it might be due to the memory process because on looking again and again our brain restores the image in memory and when brain will get the exact image this will be because of the stored information that has been retrieved from the memory.