TOPIC 2: SENSATION AND PERCEPTION
Our happiness and success are dependent on our ability to make sense of our environment in
beneficial way.
Sensation involves the process of gathering millions of meaningless sensations and changing
them into perception. This process happens very high speed and we are not aware of it.
Perception is the way in which the brain selects, organizes and interprets information
collected by the senses.
Types of senses
Vision, audition and balance(ear), taste(tongue), touch(skin) and olfaction(nose)
Vision(eyes)- Takes in light around us and sends the visual information to the brain
Audition & balance(ears)-has two functions hearing and maintaining body balance
Taste(tongue)- this is the sense organ for taste
Touch(skin)-this is the largest sense organ with special neurons that transmit distinct
sensation of touch-pressure, vibration, pain and many more.
Olfaction(nose)- the nose is an olfactory organ which helps us to perceive different
smell.
SENSATION
It is the process of receiving information from the outside of the world, translating it and
transmitting it to the brain. To better understand this, it is important to define this
Transduction – The first things each sense organ must do is to change or
transform physical energy into electrical signals that are sent to the brain for
processing.
Adaptation – A short period after putting things on like cloths, we no longer
feel them. This is called adaptation which refers to the decreased response of
the sense organ.
After the sense organs have received the signal from the environment and transmitted it to the
brain, the next process is to quickly changing the sensation to perception.
Example of sensation
Pain sensation
Gate Control Theory – It’s theory of pain say non-painful impulses shift
attention because they compete with pain impulses to reach the brain.
The competition creates a congestion that limit the number of impulses
that can be transmitted to the brain. When we rub the injured area, it
increases the transmission of non-painful impulses thereby reducing
the pain i.e. have you ever noticed that sometimes a headache comes
and go? This is particularly the case when you shift your attention to
some other activity. This phenomenon is called the gate control theory
of pain.
PERCEPTION
Our senses are the gateway through which we pick information from the environment. After our
organs pick information, the next process is Perception.
Perception is concerned with identifying the process through which we interpret and organize
information and giving it meaning.
Perceptual Threshold
Threshold refers to a point above which stimulus is perceived and below which it cannot be
perceived.
Absolute threshold is the intensity level at which a stimulus such that a person will have 50%
chance of detecting it
A subliminal stimulus has an intensity that gives a person less than 50% chance of detecting the
stimulus.
Perception and nature of stimulus.
Rules of Organization
When you are in a stationary vehicle and vehicle in the next lane moves and you get a sensation
that your vehicle was in motion, you have perceived motion where there was none. In
perception, there are many organizing principles called gestalt law.
Rules of organization as identified by Gestalt psychologist stated that our brains combine and
organizes individual pieces of information into meaningful perception. The rules are as
follows;
Figure ground – we tend to automatically distinguish between figure and ground.
Similarity – The rules states that in organizing stimuli we group together elements that
appear similar.
Closure – In organizing stimuli, we tend to fill in any missing parts of a figure and see the
figure as complete.
Proximity – In organizing stimuli we group together objects that are physically close to
each other.
Continuity – we tend to favor smooth or continues paths when interpreting a series of
points or line.
Weber’s Law – Can you remember an instance when you were asked to lower the volume of
some music you were playing and get your parent insisting that you did not do so when in
actual fact you did?
This problem involves measuring the difference in threshold between stimuli. To solve this
problem Weber (1834) developed a concept of just noticeable difference or JND which refers to
the smallest increase or decrease in intensity of stimulus that a person is able to detect.
Perceptual Consistency
Perception is full of interesting puzzles; as the image things or people casted on our retina
changes but we don’t perceive them as changing in size and shape. i.e. when we listen to song,
we like sang by another musician, we are still to recognize the song although it sounds different.
This phenomenon states that our brain maintains object as being constants despite the fact that
they change in size and shape.
Perceptual consistency – refers to the tendency to perceive size, shape, brightness and colors as
remaining the same though their physical characteristics are constantly changing.
Perceptual consistency is important in our life because without them we would spend a great
deal of time and effort re-identifying sensory inform in our environment every time we
experience them.
Depth Perception
Our retina receives information in only two dimensions (length and width). Our brain translates
the images into three-dimensional perspective. This process is achieved by use of both
monocular depth cues which require one eye and binocular depth cues which require both
eyes.
Illusion (when perception fails) – There are however instances when our perception fails us
and we are likely to see unlikely things. Illusion is compelling but incorrect perception e.g.
Ponzo illusion, Muller-Lyer illusion and Ames room
Application of Illusion.
Creating Movement – Max Wertheimer who was a gestalt psychologist and father of
flashlights used in billboards, used flash lights in succession to give an impression that
the lights were in motion. He called this illusion Phi movement which refers to the
illusion lights that are actually stationary seems to be moving.
Creating Movies – In 1893, Thomas Edison created motion pictures. Apparent motion
involves an illusion that a stimulus or object is moving in space when actual fact the
object is stationery.
Creating Virtual Reality – virtual reality refers to a perceptual experience of being inside
an object, moving through an environment. This technology is used in psychotherapy to
treat people with fear.
FACTORS AFFECTING PERCEPTION
Perception is subjective in that the way in which one person attaches meaning to information
received by the way of the sensory receptors can be different from one person to another.
The factors that influence perception resides in
(a) the conditions within the perceiver
(b)the characteristics of the target object
(c) the relationship between the stimuli and the environment.
The perceiver: 1. Attitude 2. Personality 3. Motivation 4. Self-concept
5.interest 6. Past experience 7. Expectation 8. Cultural values
Target Object: 1. Novelty 2. Motion 3. Sound 4. Size 5. Background
6. Proximity 7. Similarity
Situational Factors: 1. Intensity 2. Preparedness 3. Repetition
PERCEPTION AND LEARNING
Perception is important for our survival because we learn what benefits our very
existence.
Perception is an important process of learning e.g. ability to learn different activities.
In mathematics student are able to evaluate graphs, use equation and so on.
Perception helps in the development of social skills especially non-verbal behavior.
Educators are able to identify students with perceptual problems and get them the help
they need.
Learning materials are organized based on the rules of organization e.g. learning from
the known to the unknown.
Educators can model the importance of learning as this will improve students’
performance.
