What is the Perceptual Process ?
The perceptual process begin with stimuli in the environment and ends with the behavioral responses of
Principle of Transformation
Stimuli and the responses created by stimuli are transformed between environmental stimulus and perception
Eye’s optical system
–> they form a sharp picture of the stimulus on the receptors of the retina
Principle of representation
Everything a person perceives is based on representations of stimuli that are formed on the receptors and the activity in the persons NS
What are sensory receptors ?
Cells specialized to respond to environmental energy with each sensory systems receptors specialized to respond to a specific type of energy
ex.: visual receptors - light, auditory receptors - pressure changes in air
Function of Visual receptors
Transduction
Transformation of one form of energy to another form
Visual pigment
Light sensitive chemical that reacts to light
Function of the network of neurons
a) traveling in the opposite directions
b) being amplified
c) being reduced or prevented from entering
Primary receiving area
Receives signals from each sense
–> located in the cerebral cortex
Which lobe can you assign to which sense ?
Occipital lobe –> vision
Temporal lobe –> hearing
Parietal lobe –> touch
Frontal lobe –> all senses, plays important role in coordination of information received from 2 or more senses
Perception
Conscious awareness of the stimulus (active)
–> top down processing
Recognition
Placing an object in a category, that gives it meaning
Visual form of agnosia
Inability to recognize objects /
Perceiving parts of the object, but not being able to identify the whole object
Action
Refers to the mere act of looking at different parts of the stimulus, no need to interact with it
–> usually involves motor activities
Knowledge
Any information the perceiver brings to a situation
Bottom up processing
Processing, that is based on stimuli reaching the receptors
–> ‘incoming data’
Top down processing
Processing based on knowledge (Schemas)
Psychophysical approach/
Psychophysics
Measures the relationship between the stimuli and behavioral response
–> presenting a stimulus and determining the persons response
Oblique effect
There is a better detail vision for vertical and horizontal lines than slanted lines
Physiological approach
Measures the relationship between
–> used to understand the physiology behind the oblique effect
Absolute threshold
Describes the minimum stimulus intensity that can just be detected
ex.: Vision –> the smallest line that can barely be seen
–> threshold is lower (finer lines can be seen) when the lines are horizontal/vertical
Human perception is variable.
How can this affect measurements ?
Measurements at one point in time can differ slightly from measurements at another point.
Method of limits
(Classical psychophysical method)
Fechner
Experimenter presents stimuli by either ascending or descending order