Perception is the interpretation of the sensation. Perception is the process of organizing and interpreting sensory information to give it meaning. The brain automatically perceives the information it receives from the sense organs. For this reason, many people refer to sensation and perception as information processing system. According to the expert, A. David(1982), the purpose of perception is to represent information from the outside world internally.
Sensory information travels rapidly through the brain because of parallel processing, the simultaneous distribution of information across different neural pathways. A sensory system designed to process information about sensory qualities one at a time (such as the shapes of the image, their colors, their movements their location and so on) would be too slow to keep us current with a rapidly changing world.
Perceiving visual stimuli means organizing and interpreting the fragments of information that the eye sends to the visual cortex. Information about the dimension of what we see is critical to this process. Shape and form are critical to perception. The term shape and form are often used interchangeably. There are many questions before us related to the perception of a shape such as how do we perceive shape and form innate, or how do we segregate figure from ground.
The shape or form is defined as one of the visual fields that are set off from the rest of the field by the visible cortex. The figure-ground relationship is the principle by which we organize what the foreground is and what is the background or leftover of the image. Some figure- ground relationship are highly ambitious, and it may be hard to tell between the figure and the ground.The figure-ground relationship is essential for the perception of shape. It is not only the characteristics of visual perception but comes under sense modalities. Following are the difference between figure and backgrounds.
The figure has a shape while the ground is relatively shapeless.
The figure is more impressive, meaningful and better remembered.
The figure usually tends to appear in front, the ground behind.
Our brain has the innate capacity for organizing perception. According to them, people naturally organize their perception according to certain patterns. The main principle of gestalt psychologist is that the whole is different from the sum of its part, e.g., thousands of tiny dots make up an image in print or on a computer screen. Similarly, when we watch a film, the frame moves a light source at a high rate, and we perceive the whole that is very different from the separate frames that are the film’s part. Following factors influence perception
Proximity: Tendency to perceive objects that are close to one another as part of the same grouping
Similarity: Similar repeated patterns are perceived as one whole than dissimilar patterns.
Law of Pragnauz: The simplest organization requiring the least cognitive effort will always emerge. Pragnauz means that we perceive the simplest organization that first the stimulus pattern.
Closure: Tendency to complete the figure that is incomplete as it yields subjective contours.
Continuation common direction: Stimuli that have a common direction are organized in perception as a separate object from those stimuli that have a different direction.
Contiguity: It involves nearness in space and time. Contiguity is the tendency to perceive two things that happen close together in time. Usually, the first occurring event is seen as causing the second event.
Common Region: The colored background defines a visible common region, and the tendency is to perceive objects that are in common area or region. The stimuli sharing a common set of characteristics are likely to be organized as one object in perception. Apart from some factors are within the perceiver that account for the organization in perception.
Experience: Experience plays an important part in a person’s perception. When a person has already perceived a group of stimuli as one object, he is more likely to perceive it as the same object in future. If a child has been bitten by a dog, he perceives all dogs are dangerous and run away at their sight. His perception of dog becomes organized in the same way. Another child who has no such experience has a different perception of dogs.
Needs and Motives: Motives and needs are very powerful internal factors that influence perception organization. If a man is hungry, he is more likely to perceive the food object whereas a man having a full meal is more likely to perceive objects in the shop other than food items.
Depth perception: The ability to see the world in three dimensions is called depth perception. The problem emerges from the fact that how the image of the three-dimensional world is projected on the two-dimensional retina. The retina directly reflects height and width, but depth information is lost and reconstructed on the brain of depth cues, different kind of visual information that logically provide information about some object’s depth. Some of the cues used for depth perception are aerial perspective, linear perspective, relative size, light and shadow, interposition, etc.
Role of learning in perception
Have you thought what extent is perception natively given by way of our inherited structures and capacities, and to what extent is it the result of our experiences with the world of objects?. However, a new question is now being asked about the reciprocal relationship between learning and perception. This new and contemporary question is: To what extent is learning, merely reorganized perception.
Learning brings about a qualitative change regarding adaptation, the most generic and simple form of optimization at an individual scale. It implies the idea of new knowledge, in the sense that the organism links what formerly appeared as an undistinguished whole. In other words, it means the capability to change its codes of meaning. Finally, we outline some basic ideas for modeling an adaptive sensor embedded in an autonomous system, which implies the former distinction between adaptation and learning. Cognition transfers the functions of phylogenetic adaptation to the spatial and temporal scale of the lifetime of an organism progressively. It is called as plasticity and structural change as learning in the cognitive subsystem. It establishes a new relation to the activity of the organism in its environment. This process appears internally as a functional hierarchisation, where the cognitive system operates as a function for the general regulation of the rest of them. Both aspects, the relation of the organism to its environment and the organization of its services are coupled with the development of a rich and versatile universe.
Perceptual illusions are misconceptions resulting from misinterpretation of sensory information. Sensory illusions are also known as false perception. For example in the dark night, a rope is perceived as a snake. The illusion is a normal phenomenon perceived by all human beings.
The illusion of motion: sometimes people perceive an object as moving when it is still. You can observe this when you are sitting in a halted train and observing the moving train in the next platform. This is called the auto kinesthetic effect. A small stationary light in a darkened room will appear to move or drift because there are not surrounding due to indicate that the light is not moving. Another is the stroboscopes motion seen in a motion picture. Another illusion related to stroboscope motion is the phi-phenomenon, in which light turned on and off in a sequence appear to move the theater marquee signs. For example, the best example of movement illusion is a series of blinking lights indicating direction.
There are quite a few illusions that can be demonstrated by drawing some lines. Muller layer illusions are the most important example of that. Two lines, with one line where arrows point inside and in another arrow pointing outwards, will look to be of different length. The one which points inwards will be perceived as shorter than the one where the arrow is pointing outwards.
The moon on the horizon looks far bigger than the moon in the zenith. The retinal image is the same for both the horizon. This happens due to size-distance relationship.
Determinants of Perception
There are many different stimuli in the world which will catch out attention and result in perceptual organization. The stimulus characteristics are important as our initial needs.
Content: A given stimulus may provide radically different perception because of the immediate content. The content creates an expectation in our brain that influences our perception at a particular movement. For example, suppose in a noisy condition we hear a sentence, ‘eel is moving.’ We will perceive the word ‘eel’ as ‘wheel’ because of the content provided by the later part of the sentence. Similarly, verbally provided a stimulus, ‘eel the orange’, one will perceive ‘eel’ as ‘peel.’ This is because the later word ‘orange’ provides an expectation for the perception of the earlier word.
Perceptual set refers to our mental expectancies and predisposition to perceive one thing and not another. Our education, social and cultural experiences shape our perception. Our learned assumptions and beliefs help us in organizing our perception. Similarly, stereotypes (a generalized belief about a group of people) help us to perceive people we meet the first time. The stereotypes determine much of our social interaction we hold about individuals and groups.
Motives and Needs
Personal views matter a lot in perceiving things available in the environment.
Social and Cultural Factors
Our perceptions reflect the effect of prior learning and therefore, if learning and socialization take place in a particular socio-cultural background it will be reflected in our perception.
The perception without the involvement of senses is called as ESP. It is perception without stimulation. It includes phenomena like clairvoyance (perceiving objects and events without the involvement of senses) and telekinesis ( controlling objects without touching them), and telepathy (refers to transfer of thought from one person to another who reside in different places)