Sensation
Sensation is the body's detection of external or internal
stimulation
Is the ability to feel something physically, especially by
touching, or a physical feeling.
a mental process (such as seeing, hearing, or smelling)
resulting from the immediate external stimulation of a
sense organ often as distinguished from a conscious
awareness of the sensory process
e.g., eyes detecting light waves, ears detecting sound
waves
Sensations
Pain
Temperature
Pressure
Touch
Special Senses
Sight
Hearing
Taste
Smell
Orientation in space
How do sensation
and perception
differ?
Perception
-the ability to see, hear, or become aware of something
through the senses.
the state of being or process of becoming aware of
something through the senses.
Perception (from the Latin perception) is the organization,
identification, and interpretation of sensory information in
order to represent and understand the presented information,
or the environment.
synonyms:recognition, awareness, consciousness,
appreciation, realization, knowledge, grasp, understanding,
comprehension, apprehension; formal cognizance
Perception can be defined as the active
process of selecting, organizing, and
interpreting the information brought to
the brain by the senses.
Sensory selection
A selection process depending on the characteristic of the
stimulus and its momentary significance to the organism.
Selected stimulus then passes through a transducer.
transducer is a device that receives energy from one system
and transmits it, often in a different form, to another
Sensation process
Sensations can be defined as the passive
process of bringing information from the
outside world into the body and to the brain.
The process is passive in the sense that we do
not have to be consciously engaging in a
"sensing" process”.
Absolute threshold
is the smallest level of energy required by an external
stimulus to be detectable by the human senses,
including vision, hearing, taste, smell and touch.
A just-noticeable difference or JND
is the amount something must be changed in order
for a difference to be noticeable, detectable at least
half the time (absolute threshold).
How sensation work
Sensory organs
Sensory organ stimulus Sense modality Sensitive cells
Eyes Light waves Vision Rods and cones
Ears Sound waves Audition Hair cells
Nose Gaseous particles olfaction Olfactory cells
Tongue Soluble substances in gustation Taste cells
saliva
skin Light touch, pressure, Cutaneous/tactile Meissner's corpuscles,
Temperature, pain Krause’ s end bulbs,
Pacinian corpuscle
Sensory adaptation
Sensory adaptation
is the process in which changes in the sensitivity of sensory
receptors occur in relation to the stimulus.
All senses are believed to experience sensory adaptation.
However, some experimental psychologists say that the
sense of pain does not experience this phenomenon.
List of absolute thresholds of the five
external senses
sight Candle flame 30 miles away
hearing Tick of a watch 20 feet away
Smell 1 drop of perfume in a 3-room apartment.
Taste 1 teaspoon of sugar in a 2 gallon of water.
Touch A bee’s wing falling on the check from a
distance of 1 cm.
Negative Afterimage. A sensation of opposing colors that occur after
staring at a colored stimulus.
the colors of the original image are maintained. Essentially, the
afterimage looks the same as the original image. You can experience a
positive afterimage yourself by staring at a very brightly lit scene for a
period of time and then closing your eyes.
Visual problem
a. Red and Green Color Blindness
They generally have difficulty distinguishing between reds, greens,
browns and oranges. They also commonly confuse different types of
blue and purple hues.
b. Monochrome color blindness
The person is sensitive only to the light-dark system and sees no color
whatsoever.
