Sensation The process through which the senses pick up

visual, auditory, and other sensory stimuli and transmit them to the brain;

Sensory information that has registered in the brain but has not been interpreted called sensation

Perception The process by which sensory information is

actively organized and interpreted by the brain The process of selecting, organizing, and

interpreting raw sensory data into useful mental representations of the world.

Eyes, ears, skin, nose, and tongue and contain receptor cells

These receptor cells receive and process sensory information from the environment

Transduction: sensory receptors (eyes, ears, nose, skin, tongue) convert the stimulus into neural impulses which are sent to the brain

Perceptual processes include:

Selection refers to choosing which of many stimuli

that will be processed.

Organization involves collecting the information into

some pattern.

Interpretation involves understanding the pattern.

Following are the group of factors1. Objective Factors2. Subjective Factors

There are a number of characteristics of stimuli that influence our perception.

1.Intensity2.Size3.Distinct & Striking4.Movement5.Novelty6.Duration7.Repetition8.Abrupt Change

1. Intensity; The louder a sound , the more likely a person is to perceive it. The brighter a light, the more likely it is to be in the focus of perception.

2. Size; A full page advertisement is more likely to be noticed than a half- column one.

3. Distinct & Striking; distinct and striking things are perceived sooner than dull and unclear things.

4. Movement; When things move suddenly in still and motionless environment ,it is quickly perceived .e.g. birds sitting quietly on tree are not quickly perceived as compared to ones about to fly.

5. Novelty; A new and novel thing is perceived sooner than old and used thing.

6. Duration; Television and radio advertisements of long duration are attended to more than those of short duration.

7. Repetition; Repetition causes us to adapt to the repeated stimulus .

8. Abrupt Change; Any change in stimulus conditions, such as increase in noise , often attracts attention.

Sometimes, perception is determined not only by the physical characteristics of stimuli but by the characteristics of the perceiver. These are

1.Motives or needs2.Interests & values3.Past experience4.Age5.Preparatory set6.Social & cultural factors

1.Motives or Needs; when people are motivated ,they tend to see and hear what they want to hear. In other words, we may be set to perceive the world in ways that agree with our motives and match our goals.

2. Interests & Values; we attend to those aspects of world that relate to our interest.

3.Past Experience; Much of our daily activity is dependent upon past experience. we have learned to react to cues & symbols. E.g., on seeing a moving line on the sky, we guess it to be an airplane.

4. Age; Age brings a change in perception as well. A child perceives things in different way as compared to a young person.

5.Preparatory Set; This refers to a person’s readiness to respond to one kind of sensory input, but not to other kinds.

6.Social & Cultural Influences ; The normal perceptual experiences of a culture may lead its members to develop perceptual biases, suggestions and prejudices.

We perceive objects in different manners as compared to their position in the environment. Objects may be moving or static, when we have to perceive motion. We may have to locate sounds and voices in the space around us.

1.Form Perception2.Size Perception3.Depth Perception4.Perception of Movement5.Time Perception

Gestaltists proposed laws of organization that specify how people perceive form.

Figure and ground are basic organizational themes for perception.Figure is perceived as distinct from the

background.Figure is closer to the viewer than the

background.Reversible Figures: Figure and ground can be

switched

Formation of a figure: There are some factors which would bring some order to perception

1.Nearness: Stimuli that are near to each other, tend to be grouped together

2.Similarity: Stimuli that are similar in size, shape, color, or form tend to be grouped together

3.Continuation or continuity: Perception tends towards simplicity and continuity

4.Closure: refers to the tendency to complete a figure, so, that it has a consistent overall form

Three types of constancy are explained briefly here:

1.Size Constancy2.Shape Constancy3.Color Constancy

1. Size Constancy: Size constancy is the tendency to perceive

objects in a consistent manner despite the changing sensations that are received by our senses. visual constancy plays an important role in helping us adapt to our environment successfully.

Learning plays an important role in the development of constancy. Once we know that certain objects in our environment have certain characteristics ,we tend to perceive them in the same way, regardless of the conditions under which they are perceived.

When we know that an object is of a certain size, we tend to perceive it as being that same size, regardless of how far it is from our eyes.

In Size constancy ,the perceiver has the ability to judge true or measured size, regardless of the distance involved.

2.Shape Constancy; When we know that the object is a certain shape ,we tend to perceive it as the same shape, regardless of the viewing angle. We have learned to make corrections in our perception dependent on the angle from which we observe.

3.Color Constancy; Colors of objects tend to remain constant in perception when we know their true color. Visual objects also appear constant in their degree of whiteness, grayness and blackness.

The ability to view the world in three dimensions and to perceive distance is known as depth perception.

“This ability helps to perceive three-dimensional space and to accurately judge distance”.

When you ride in a moving vehicle and look out the side window, the objects you see outside appear to be moving in the opposite direction

Objects very far away, such as the moon and the sun, appear to move in the same direction as the viewer

Perception of Movement; Movement or Motion is perceived by following the progressive change of an object’s position in space with time. It has two types.

1.Real Movement; The perception of the actual movement of objects in the world is termed as “real motion/movement perception”.

2.Apparent Movement; It is movement perceived in the absence of physical movement of an image across the retina. This can be produced by a rapid succession of motionless stimuli that minimize the changes that occur in real movement. There are several types of apparent motion/movement:

We perceive time in , seconds, minutes, and hours which pass into days weeks months and in years and even in centuries. Time is perceived in terms of Past, Present, and Future

Perception of time is less in children than elders

Several factors influence time perception:

1. Subjective( age, activity, motivation, intelligence )

2. Objective: