Task 1 measuring experience Flashcards
Eyes
two spherical sensors called “eyes”, which contain a light sensitive chemical, to sense light
Ears
are fitted with tiny vibrating hairs so sense pressure changes in the air
Skin
small pressure detectors of various shapes imbedded under the skin to sense stimuli on the skin
Nose/mouth
chemical detectors detect gases that are inhaled and solids and liquids that are ingested
vestibular
fluid in the inner ear that keeps the body in balance
Absolute threshold
the minimum stimulus intensity of sound that can just be detected 50% of the time
Difference threshold
the gap between perceiving a stimuli as different or not (for humans and weight its 2%)
Magnitude estimation (Stevens)
first presents a standard stimulus and assigns a value to it. Then different strengths of the stimulus are presented to the subject and he/she assigns new values proportional to the standard value.
response compression
when the increase in perceived magnitude is smaller than the increase in stimulus intensity (light)
Response expansion
when the increase in perceived magnitude is larger than the increase in stimulus intensity (electro shocks)
Response linearity
When the increase in perceived magnitude is the same than the increase in stimulus intensity (length of a line)
Phenomenological method
o A person is asked to describe what he or she is perceiving or to indicate when a particular perception occurs
o Often used to test perception of people with brain damage
Response criterion
How likely a person is to consider a stimulus as seen or not seen (e.g. somebody reports a light when he sees the slightest light and another person only reports seeing something when she is 100% sure)
Fechners law
o S = k * log * r (higher stimulus higher sensation) (constant physical stimulus intensity and sensation intensity) (adjusts webers law)
Classical psychophysical methods (Fechner)
Limits: either presenting stimuli in ascending or descending order doing both several times to calculate the average threshold
Adjustment: only increasing or decreasing and the participant can determine his threshold by himself
Constant stimuli: five to nine different stimuli presented in random order
Webers law
The webers fraction (the percentage of how much you could detect changes in a stimulus) stays the same with increasing stimulus (detectable difference fraction, power of the stimulus) (not always right)
Stevens power law
P = KSn. Perceived magnitude, P, equals a constant, K, times the stimulus intensity, S, raised to a power, n (combines Fechner and Weber)
o N the way how perceived magnitude changes as intensity is increased (>1 response expansion <1 is associated with response compression)
Psychometric
- is a field of study concerned with the theory and technique of psychological measurement.
- Measuring what happens in our mind
Principle of transformation
stimuli and responses created by stimuli are transformed, or changed, between the environmental stimulus and perception
Principle of representation
everything a person perceives is based not on direct contact with stimuli but on representation of stimuli that are formed on the receptors and on activity in the persons nervous system
Stimuli Step 1 and 2
o Environmental stimulus:
the tree that the person is observing (step 1)
o the perception of the tree is based on light reflected from the tree (step 2)
Connection between step 1 and 2
The environmental stimulus is transformed into the image on the retina, and this image represents the tree in the persons eyes
Receptor processes/Transduction (step 3)
o Sensory receptors: are cells specialized to respond to environmental energy, with each sensory system’s, there are different systems for different input
Transduction
The change from e.g. light energy to electrical energy
Neural processing
o When transduction happen thousands of visual receptors provide electrical signals to a network of neurons, first in the retina, then in the back of the eye and then in the brain
o This complex network of neurons transmits signal to and trough the brain, and changes (or processes) these signals as they are transmitted.
Changes are created by the different routes and obstacles
Behavioural response
o The person perceives the tree (step 5)
o the person recognises it (step 6)
o action (step 7)
Bottom-up processing
is based on the stimulus reaching the receptors
Top-down processing
refers to processing that is based on knowledge
Psychophysical approach
measures the relationship between the stimuli (step 1 and 2) and the behavioural response (step 6-7) (horizontal and vertical lines resulted in better vision)
describes the similiarity between the real obstacle (physical) an you representation (psycho)
Physiological approach
measuring the relationship between stimuli (1&2) and physiological response (3&4) and the relationship between physiological responses (3&4) and behavioural responses (5-7)
