Water or Rock in Motion: Demystifying the Waterfall Illusion

Water or Rock in Motion: Demystifying the Waterfall Illusion

Introduction

For centuries, artists and scholars have been intrigued by the nature of optical effects, illusions, and perceptions. Optical illusion art generates perceptive responses with the dynamic qualities that provide sensations and illusions to the individuals. Further, optical illusion art is portrayed as a higher Science that is linked to delicate retinal art based on the theories of visual illusions and the perceptions of various movements. In this paper, there will be a detailed psychological and physiological analysis of the waterfall illusion to offer a scientific explanation based on peer-reviewed journals, which are supported by experimental evidence.

Perceiving optical illusions can be fun; however, trying to breakdown how they work is a more tasking and justifiable task. They reveal the capacities and restriction of the human eyes and specify how these the limits of perception are set (Ghada, 2018). Illusions allow us to analyze the different cognitive sub-processes that underly in our perception. From a Scientific approach, illusions are aimed at revealing our failed perception or the existing dysfunctions of our visual apparatus, but they are aimed at revealing the degree of power in human perception. Human perception is aimed at strengthening and intensifying the sensory apparatus to orientate, make a quick response, perceive in an efficient and specific manner.

To understand the critical aspects of optical illusion art, it is important to define the term to understand what it focuses on in the creative arts. As used in the creative arts, Ghada (2018) defines optical illusion arts is a form of abstract or concrete art that is made up of non-representative geometric figures that can create various types of optical illusions. Optical illusion art aims at exploiting a functional relationship between the brain and the retina in the eye. Some of the visual stimuli tend to cause confusion between the eyes and the brain, which results in the perception of an irrational optical occurrence that artists use to present a full effect of optical illusion art.

The waterfall illusion is considered a motion illusion that is experienced after watching a stimulus in motion towards one direction and then looking at the motionless scene. The stationary scene appears to be in motion on the contrary direction of the movement of stimulus that was watched previously (Wade, 2018). In the water illusion, the main question that needs to be addressed is, why is there motion in the adjacent rocks? This tends to create confusion between the test phases related to the motion aftereffect. The water cannot be stopped in a waterfall, and it required a motionless stimulus to conduct the test. The succeeding descriptions of the motion aftereffect were based entirely on stimuli, which was considered a rotating spiral or subdivided discs that could be stationary after motion so that a similar pattern is used for testing and adaptation (Wade, 2018).

Physiologically, the illusion is explained to involve a decline in the sensitivity of the neurons at various parts of the brain. This could occur because the brain neurons become exhausted, and therefore, they change their responsive gain towards sensitivity (Verstraten, 2017). However, it can also happen because the neurons alternate their sensitivity or what is referred to as the contrast gain to stimulus. This difference in the movement between two objects of things is what is referred to as the contrast. Neurons are known to change what kind of contrasts depending on the greater or lesser sensitivity reactions. From this explanation, when watching stimulus in motion, in this case, the moving waterfall, the neurons detect motion in the downward direction and become less sensitive to the moment and the speed in the downward direction (Pérez-Schuster et al., 2016). The result when you change your visual direction, the neurons that had detected the upward direction become active in making a comparison. This translates to the appearance of motionless objects, which are the rocks, moving in the upward direction.

From a psychological perspective, evidence suggests that there is a change in the position of the perceived stimulus while experiencing the motion aftereffect. Findings by Chen et al., (2019) show that the amount of movement is dependent on the inducer’s speed which matches with the observation of the speed-related to illusionary motion depending on the inducer’s speed. However, despite the fact that this suggests that objects are in motion and changing position, it is not psychologically conclusive. Therefore, it only indicates that objects are experienced as not existing in their original position (Nakashima et al., 2015).

The two scientific perceptions on the Waterfall illusion still do not offer a conclusive explanation. It can be considered a simple experience of objects in motion in the opposite stimulus path with a change in direction. It might also involve the experience of objects in motion in the opposite stimulus direction with no change in direction. Or it could be a complex occurrence that consists of the experience of moving objects and changing positions out of the center of the visual field with no movement at the center. Or it can be an experience of objects in motion and changing position but jumping back to the initial position before making the change in direction once again.