Sensation and Perception

Our link to the external reality is through the senses – the windows of the outside world. Through our senses or sensory organs, we come to know our world and what we sense often affects our behavior.

Sensation The process of accepting or receiving

the stimulus by the senses. It is the experience of sensory

stimulation

HOW DOES IT OCCURs?

Sensation – occurs when energy from an external or internal source stimulates a receptor cell in one or more sense organs.

Receptor Cell - a specialized cell that responds to a particular type of energy.

Elements: Stimulus – any form of energy that can

cause awareness or change. Receptors – responsible for the detection of

stimulus. Transduction – the process by which the

senses by which the senses changes or transfer stimulus into impulse which will be transmitted to the brain for perception.

Absolute Threshold How much stimulus is necessary in order

to see, hear, taste, smell or feel something? When is a stimulus said to be detected?

The reception of stimulus depends on five factor: Quality of the stimulus Quantity or intensity of stimulus Timing or distinctiveness Location or source of the stimulus Difference in perception

Absolute threshold Absolute threshold is the minimum amount

of stimulus energy that an individual can detect.

It is the smallest intensity of energy that can be detected 50 percent of the time.

It is the lower limit of sensitivity.

When there is no sense of awareness of the stimulus and therefore they escape unnoticed, the stimulus is in the Subliminal threshold.

When there is an increase in intensity, the stimulus produce pain and make the individual uncomfortable, the stimulus is said to be in the terminal threshold.

SENSES ABSOLUTE THRESHOLD

Light Sees a candlelight 30 miles away on a clear, dark night

Sound Hears the tick of a watch 20 feet away under silent situation

Smell Sells the scent of one drop of perfume diffused in a three-room apartment

Taste Taste the sweetness of one teaspoon of sugar in 2 gallons of water

Touch Feels wing of a fly 1 cm away from the cheek

Senses that responsible for Sensation Eyes (Sight) Ears (Sound) Tongue (Taste) Skin (Touch) Nose (Smell)

Perception Perception is the process of interpreting

or giving meaning to the stimulus received by the senses.

Factors that influence perception EXTERNAL FACTORS

Intensity of the stimulus Repetition of the stimulus Contrast in the stimulus Movement of the stimulus Change in the stimulus

Factors that influence perception Internal Factors

Motivation Training of the Perceiver Experience of the perceiver Mental set Interest and attitude

Types of perception

Gestalt Law of Organization It maintains that the basic perceptual

process operates on the basis of a series of principles that describe how to organize bits and pieces of information into a unified whole which includes closure, proximity, similarity, simplicity and continuity.

Law of closure When a figure has a gap, one tends to

see it as closed or complete.

The figures are open or incomplete, Yet, they are perceived as closed or complete. Perception of closure is to close or complete the figures mentally.

Law of proximity The tendency to group together those

elements that are close together.

One tends to see pairs of dots rather than a row of single dots.

Law of similarity The tendency to group together those

elements that are similar in appearance.

One sees the above figures as horizontal rows of circles and squares instead of vertical mixed columns.

Law of continuity The tendency not to break the

continuous flow of lines or design in one’s perceptional awareness allows continuity.

Law of simplicity The tendency to perceive pattern in

most basic, straightforward, organized manner possible.

The figure above is seen as square joined by 2 lines rather than letter “w” on top of letter “m”. Having choice in interpretation, one usually prefer the simple one.

Other types of perception1. Visual perception 2. Auditory perception – interpretation of

sound3. Depth perception – the ability to

perceive the world in 3 dimensions.4. Haptic perception – the earliest sense

to develop in fetus( sense of touch).5. Perception of time

Special kinds of perceptions1. Telepathy – is the transfer of thought

from one person to another without the regular use of the senses.

2. Clairvoyance – is the ability to see without the use of the eyes and can reveal information that may have not been received by ordinary or regular sensation.

3. Precognition – the ability to foretell future events.

4. Psychokinesis – is the ability to make object move by thought process alone.