Perception is the interpretation of sensations experienced by any person at any point of time to study them in a meaningful fashion. It adds certain individuality.
How do we organize our perceptions?
However, the perception has individuality attached to it, nevertheless, there are certain quantities that never change between individuals. Those are the constancies.
Size Constancy: This is the tendency in which people interpret any object is having to be the same size, irrespective of its distance from the viewer.
Shape Constancy: This is the tendency in which people interpret any object is having the same or constant shape, It doesn’t matter whether the shapes get changes on the retina.
Brightness Constancy: When any person perceives the clear brightness of the object, even when the intensity of brightness gets changed then this tendency is Brightness constancy.
Figure-Ground Relationship: When we perceive an object as its existing property even on the background then it is Figure-Ground Relationship.
Reversible Figures: It is a visual illusion in which the figure and ground can be reversed. Example, Cube.
Gestalt Principle of Grouping
We have discussed the Gestalt Principle earlier. According to it, the Human tendency is to organize isolated stimuli into groups and this is done with the help of these five characteristics.
Proximity: This is the tendency to perceive objects that are close to each other as part of the same grouping; physical or geographical nearness.
Similarity: This is the tendency to perceive things that look similar to each other as being part of the same group. Example, A sports team grouped by their jersey even they are scattered in the field.
Closure: A tendency to complete the figures which are incomplete. Example, Dotted circle.
Continuity: When any person perceives any objects in its simplest and continuous pattern, without any complexity and broken pattern then it is called Continuity.
Contiguity: When a person perceives two things when they are closed together and related to each other then it is called Contiguity.
Common Region: An object is perceived when they are in a common region then it is called Common region.
This is the capability of an individual to perceive the object in three dimensions. People, in general, get Depth perception from their infancy age. But, those who don’t have their sight are unable to deal with the depth perception.
There are many cues exists for depth perception. Let’s discuss each of them below:
Monocular Cues (Pictorial Depth Cues)
The cues which are used to perceive depth with the use of one eye only. Artists basically use this cue to give the illusion of depth in their paintings and drawing.
- Linear Perspective: This is a monocular depth perception which cues the tendency for parallel lines to appear to converge on each other. These are generally used in the picture to portrait the two long-distance roads are converging to each other at a long distance.
- Relative Size: This is another monocular depth perception that occurs when objects that a person expects to be of certain size appear to be small and are, therefore, assumed to be much farther away.
- Overlap (Interposition): This is the assumption that an object that appears to be blocking part of another object is in front of the second object and closer to the viewer.
- Aerial (Atmospheric) Perspective: The objects which are farther away from the viewer which looks hazy due to tiny particles of dust, dirt and other pollutants. The perceived distance observed as greater due to this haziness.
- Texture Gradient: When any textured surface appears finer and smaller when the distance from the viewer increases.
- Motion Parallax: While traveling we see objects which are closer they seem to move very quickly and the objects which are farther away seem to move slowly.
- Accommodation: This is all about the accommodation of the eyes. In this monocular cue of the depth perception, the brain tends to adjust the lens of the eye by fetching information from the near and far object.
The cues which are used to perceive depth with the use of both eyes. Due to two eyes, there is visual differences in patterns are observed.
- Convergence: When our two eyes rotate just to focus on a single object which results in a higher level of convergence for closer objects and lower level of convergence for distant objects.
- Binocular Disparity: The eyes never see exactly the same image. This creates the greater image’s differences between two eyes for the close object, whereas smaller differences in images between the two eyes for distant objects.
An illusion is a perception that does not correspond to the reality. It is basically visual stimuli that fool the eye. Let’s discuss the basic difference between an illusion and hallucination. An illusion is the distorted perception of something that really exists, whereas, a hallucination originates in the brain, which never exists.
Research on illusions is really helpful for psychologists as well as neuroscientists, as these studies provide valuable information about the working of sensory receptors and sense organs along with human’s interpretation of sensory input.
When the brain’s visual system attempts early sensory processes, subsequent processing or higher-level assumptions then illusions tend to take place.
Perceptual Set (Perceptual Expectancy): When previous or existing expectations or experiences influence the perception to perceive any object then it is called a perceptual set.
Top-down Processing: When a person uses his pre-existing knowledge or awareness to organize any individual features to make a unified one. Example, Puzzle to complete a picture.
Bottom-up Processing: It is the reverse of the Top-Down processing. When a person uses the smaller features to build up the complete perception.