Tut 1 Completly done !! Flashcards
What is bottom up processing ?
- It is data based processing
- A Stimuli reaching receptor which does not evaluate
- Sensation
- Information from enviorment to brain
What is top down processing ?
- Prior knowledge memories, and expectations are involved
- Receptors or Brain evaluate the picture u face or see
- Perception
Name all the receptors
The receptors are
- visuell receptor
- auditory receptor
- touch receptors
- smell and taste receptors
Visual receptor respond to ?
- light-sensitive chemical (responds to light)
Auditory receptor respond to ?
- pressure changes in the air (tiny vibrating hairs to sense)
Touch receptors respond to ?
- sense stimuli on the skin (’pressure detectors under the skin)
smell and taste receptors respond to?
two types of ‘’chemical detectors’’ to detect gases that are inhaled liquids that are ingested (entering mouth and nose)
The Perceptual Process:
- Exposed to a distal stimuli in the Environment
1.2. Making a stimulus the center of attention (attendance stimulus) - Reflection of light
- Receptor processing: What we perceive is transferred to an image on retina (proximal stimulus)
3.2. Transduction: (light into electricity) - Neurol processing = Transmission/ electrical signals activate other neurons TILL HERE IT IS TOP DOWN
(From eye to the visual cortex) - Perception: Conscious awareness of stimuli
- Recognition: Categorise object based on knowledge
- Take action (looking closer or move close )
What is the principle of representation?
Everything a person perceives is based not on direct contact with stimuli but on representations of stimuli that are formed on the receptors and on activity in the person’s nervous system.
Explain transduction (Step 4):
Transduction: visual pigment (reacts to light) ->gets transformt in electrical energy
Which brain regions are involved regarding senses:
- vision -> occipital lobe
- hearing -> temporal lobe
- skin senses -> parietal lobe
- Frontal lobe: Involve the coordination of information received through two or more senses.
What kind of function does knowledge have regarding the perceptual process?
- Involved in all steps
- Knowledge is any information that the perceiver brings to a situation.
- most valued in step 5,6,7
What is agnosia ?
Inability to recognize objects (do to brain tumor)
Name the methods of figuring out the absolute threshold by Fechner!
All of them want to determine the smallest intensity needed to still realize a different!
- That can be determined by:
- Method of limits
- Method of adjustment
- Method of constant stimuli
- Adaptive testing
Name the limitations of the absolute threshold:
Perception can be variable. Each person has different senitvitys
Explain the method of limits:
- Stimuli will be either intensity increasing or intensity decreasing per round
- First ‘‘no’’ crossover point (stimuli not perceived)
- all crossover point will be averaged to identify absolute threshold
Explain the method of adjustment:
The observer (not the experimenter) adjusts the stimulus intensity continuously until he or she can just barely detect the stimulus. Again then the average will be counted.
Explain the method of constant stimuli:
- Most accurate because of the random order of intensity
- the stimuli which u reported to realize 50 % of the time will the threshold value
What is the magnitude estimation experiment by steven?
- Researcher sets the magnitude of the stimuli and lets the participant decide if the next stimuli will be larger or smaller!
- To see how perceived intensity changes in comparison to the actual intensity
- It was done because by Fechner, only compression existed and steven figured out the expansion of a stimuli intensity trough out the experience!
What is response compression ?
Perceptual magnitude (perceptual intensity) is lower than the actual intensity.
What is response expansion ?
Perceptual magnitude (perceptual intensity) increases more than intensity !
Define Stevens power law :
- Function: P = KS^n.
- Exponents less than 1.0 response compression (Fechner)
- exponents greater than 1.0 are response expansion (Additional factor)
- If n equals to 1 it is weber law
What influences the determination of threshold intensity ?
- Characteristics of the person
- if the response criterion is low
or if the response criterion is high
Basically how sensitive an individual is
What is the signal detection theory ?
Creating decisions under uncertainty
- determines at what point is a signal strong enough to notice it
- Gain the repsond criteria
What is the difference between sensation and perception?
- Sensation is using the senses through touch, smell, sight, sound, and taste and perceiving infromtaion from it without interpeprtating
- ‘Perception’ can be defined as how we interpret the world through our senses.
What is the weber law ?
- Its a linear constant function. (JND/S =K)
- One standard weight and a comparison weight.
- Comparison weight increases to identify JND
- S = Standard value
- K = Weber fraction (the amount needed in % to detect change)
Define Fechners law:
Extansion of webers law:
- the intensity of the stimulus increases, the amount of intensity we need to perceive a change does not remain constant
- S = KlogR
- Descrition = Curve goes up fast then decreases over time and stays at the same lvl
- only describes response compression
What is Prosopagnosia ?
- Patient can see but not recognize faces
- Sensation works but perception does not
What is the adaptive testing ?
- Similar to method of limits
- the difference is: Stimuli around the threshold are presented
What do the weber fechner and stevens law describe ?
They all describe the relationship between intensity needed for different exposure in a relationship with magnitude (size/weight)
Key facts about perceptual process:
- active
- contiously changing process dynamic
- peception does not show reality but shows what is important for brian
Name the methods of measurement on perception:
- Psychophysical approach Telling the difference between two stimuli
- Electrophysiology (EEG observing neuron firing rate after a stimulus in comparison with two stimuli)
- Neuropsychology (Measuring brain activity whil person discribes just a stimuli)
What is the oblique effect:
We perceive straight lines (horizontal / vertical) line more clearer then crossed lines because of our environment.
