The role of basic senses
Our senses first connect us with the external world. External-world consists of physical matters in different forms. We have the tools through which we come to know what is around us. Our sense mechanisms help us to be aware their existence.
Our basic senses include ability to see objects, ability to hear sound, capacity to feel through our skin and body surface, ability to smell and taste. They are mediated by the sense organs which takes the signal to our brain.
Do we have other senses ?
The basic senses helps us with the basic signals which they generate through our organs but the brain processes these signals in various ways to make us sensitive to other aspect of the physical world and also about our own self to control ourselves in various ways.
If we close our eyes and take our hand towards our nose, we can do it accurately. So we can sense our body parts and their locations and movements through the space.
Perception
Imagine that you are walking on the road and there is traffic on the road. How do you know, you are walking on the road? You feel the hard surface of the road. You see the stretch of road in front of you. You can hear the sound of the traffic and you can see the surrounding environment. Hence you become aware that you are walking on the road. You perceive yourself to be walking on the road.
As you can see from the above that different senses must integrate to develop the perception. Although you may not be attending to any specific matter separately but still you become aware that you are walking on the road. So perception is a preattentive phenomenon. And it is a direct in nature because you directly know of the object, environment or a concept.
Why memory is important for perception
When you wave your finger in front of someone, he immediately becomes aware what is happening before him. He is recognizes that what is that being moved in front of his face. It is your finger. How did he come to know of it? He must have seen the structure of the finger and remembers it. He unconsciously breaks the impression generated from is visual field into perceptible divisions and then come to know that moving structure is a finger and it is the finger of the man in front of him.
How do we know that something is moving in front of us? We see a structure of an object and also become aware that on a time difference the objects position changes in the space. This means we must remember the previous positions of the object to compare the various changed positions of the object that is moving. This proves that the perception of motion is a result of interaction happening between the various parts of the brain that processes our sensory stimuli and also uses the impressions that we are continuously storing in our memory over a period of time.
Spatial Perception
When we move around we can clearly understand where the objects are placed. Our eyes and ears help us to locate and understand the specific location of an object. We can understand relative distance between several objects and also from our own body. We also become aware of how the objects are distributed in the space before us.
A blind person can understand shape by remembering his own hand movements. This kind of memory may be termed as motor memory. So every time you ask a blind man to trace a circle he will be able to tell you that what shape he has traced. But if he suddenly gets back hi vision and sees a circle. He will never be able to tell that the shape is a circle. this is because what he remembers is what he traced moving his hand. He has no memory of a circles visual shape. But if he traces it out on the surface, he will be able to connect the visual experience with his motor memory of hand movements that he used during the tracing action.
It is seen that blind persons who are lacking their vision from their birth can move around in their familiar places. And they do it quite effectively. This means they remember the concept of arrangement of objects in the spece around them. They carry a mental map of how each of the objects are placed in the space within which they operate.
Normally a person with vision will have the map defined in some way in the brain and a blind person will have it in a different way in their brain. But one thing is true that in both of the cases t the entire spatial concept is stored in the memory in some way or other.
Consciousness
To be conscious simply means to be aware of the surrounding environment and actuvities. A conscious person can feel, think, move, understand and cmmunicate. He can remember things of past, plan for future and relflect on what he remembers.
Being unconscious similarly means the opposite. An unconsious person cannot think, understand, move, communicate, remember and reflect.
But to be conscious a person has to be capable of percieve things and also should be able evaluate the precieved idea or concept. The prcess of evaluation will be possible only if he can remember the past experiences, compare them with new experiences. This means to be conscious a person must have memory.
On the other hand if a person gets the sensory inputs in his bain but cannot repond to it he is no more conscious. If the memory recall process is affected and a person cannot remember the past data, we call it clouding of consiousness. A person is confused because he cannot remember where he is, what time it is, with whom he is speaking, or even who he is. This is also known as disorientation. Such a person's thinking become incoherent and
Today, the connection between perception and memory is increasingly recognized ( Murdock, 1979; Turvey & Shaw, 1979). When we try to identify the processes used in perception, we find that we must be aware of a situation, attend to it, and identify it by recalling similar situations. Often, when memory fails, we imagine what must have happened to fill the gaps. We can recall and imagine something seen or heard, even smelled, tasted or touched..
References
Memory and brain, Chapter : Perception
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