Intro
There has been controversy amongst cognitive psychologist in regard to how our brain perceives the world around us. Theorists of perception have argued for two schools of thought. The first theory of perception is known as direct perception, otherwise known as “bottom-up” processing. Direct perception theorists such as JJ Gibson (1966/1972) have argued that there is a suitable amount of information in our environment for us to make sense of our world without our brains inferring what is around us. Constructive perception is the other school of thought argued by theorists of perception. Constructive perception is otherwise known as “top-down” processing. Helmholtz (1860), among other top-down theorists, suggest that we infer much of what we know about the world. Throughout the history of perception research, there has been compelling and legitimate arguments for both schools of thought.
Intro to direct perception
Direct perception is a theory in cognitive psychology that explains how our brains perceive incoming raw data using our senses. This theory suggests that perception begins with the senses. JJ Gibson, the theorist behind the “ecological theory”, believed in direct perception. Gibson’s theory claimed that background, horizons, and other objects in the environment play a significant role in the way people perceive their world. Specifically, Gibson believed that movement was a major factor in perception (“Optic Flow”, 2018). Movement has shown to aid the perception of things in our environment with greater accuracy compared to things that are static in our environment. For instance, a moving horse on the horizon is more likely to be distinguished as a horse than a horse that is not moving at all (Thompson, 2018). With movement as a basis for his theory, Gibson developed three main ideas for his general theory of visual perception. The first part of his theory is optic array, which is the patterns of light entering the eye and available to the retina. Optic array essentially provides clear information regarding the space and objects surrounding us (“Optic Flow”, 2018). Perception essentially picks up the abundance of information from the optic array in a direct manner with very limited processing involved (Simple Psych). The movement of objects around us provides the viewer with textured gradient. This allows us to perceive information such as speed and distance. Movement is necessary for textured gradient to be perceived by the brain, making it a critical part of perception (“Optic Flow”, 2018). Texture gradients and linear perspective allow us to perceive depth. These are known as invariants because they provide us with information that remains consistent and unchanging (Simple Psych). Gibson explains it is fairly automatic for people to filter information from the optic array because we are so tuned in to our environment (“Optic Flow”, 2018). Our evolutionary ability to interpret unstable sensory input allows us to experience a meaningful and stable view of the world around us (Simple psych).
Evidence of bottom up
Optic array can be seen in a few different cases. For example, if you are sitting in the passenger seat of a car, the car moving next to you may appear to be going at a steady pace in the opposite direction. However, as soon as they begin to move out of the perceivers optic array, the car appears to speed up and move away at a rapid pace (https://bryonysheppardpsychology.wordpress.com/2013/09/22/gibson-vs-gregory-perception/). While the car is not moving any faster, we perceive it as going faster due to our optic array.
Intro to constructive perception
The constructive perception theory focuses on how our perception is a top down process. Theories such as Helmholtz’s Likelihood principle are the basis of constructive perception. Helmholtz states our expectations based on our prior life experiences form unconscious assumptions about the environment (Thompson, 2018). Unlike bottom up processing, top down processing starts with the brain. Richard Gregory’s (1970) theory suggests people construct their perceptions using information based their experiences and expectations. These experiences have a critical role in our visual perception. Constructive perception goes further than what is being perceived. We use inferences and expectations to form a perceptual view of the world around us. Gregory’s theory is said to be more plausible than Gibson’s, as there is strong evidence to show the brain and long-term memory have influence on perception (Simple Psych).
Evidence of top down
There is strong evidence that supports constructive theories. For example, when we use context in object recognition, we tend to see the item that fits our expectations (Thompson, 2018). In one demonstration, Gregory shows us that we have an innate need to reconstruct a face. This is done with a hollow mask of a face. Our brain reconstructs the hollow side of the mask into a real three-dimensional face based off of our past experiences. Once the facial features appear to us, our brains refuse to see the hollow mask as hollow simply because it is so unlikely. Instead, we perceive a normal looking face. This experiment, known as the Inverted Face, emphasizes Helmholtz’s likelihood principle.
Another experiment in which top down perception can be seen is with the Necker cube. Upon staring at the crosses on the Necker cube, the orientation of the cube can change. Although the figure is only one physical pattern, it produces two differing perceptions. This demonstrates top down knowledge because the brain develops two applicable hypotheses for the orientation of the cube, and incapable of deciding which orientation is correct.
Critical of top down
Although much of Gregory’s indirect perception theory is solid, much of his theory is based off of artificial stimuli. Movement is a critical part of the way we perceive the world, and a flaw in Gregory’s research is often about static perception. Even when we are not moving, our eyes hardly ever remain on a fixed point as Gregory’s research has perceiver doing. While bottom up theory has its flaws, there is very strong evidence that we can see truth in such as optic flow patterns.
Critical of Bottom up
A piece of Gibson’s theory involves a term called affordances, which is the role of physical surroundings, psychological state, and physiological state in our perception. It is said by Gibson that in order to know what objects in our environment represent, we must combine certain elements with our optic array. This is controversial because this concept cannot be applied to every culture because different uses for certain objects may have been a learned idea rather than an afforded one (https://bryonysheppardpsychology.wordpress.com/2013/09/22/gibson-vs-gregory-perception/).