Unit 4 Flashcards
Explain the difference between bottom-up and top-down perception
Bottom-up: What we perceive based on sensory inputs ex: You would perceive this “13” as a straight line next to a squiggle line”
Top-Down: The influence of context, previous experience and biases on the way we perceive a stimulus ex: You would perceive this “13” as a 13 because you know your numbers or as “B” if I put it in the context “A 13 C” (hard to show digitally lol)
What is a perpetual set?
Mental predispositions or biases that influence what we perceive. They are often learned and greatly impact our perception of the world
Give an example of how perceptual sets influence your perception
“other race effect”: It is easier to recognize ppl of our own ethnic/cultural background bc of our learned experiences
What are our perceptions based on?
Sensation and our expectations
Give an example of how your brain builds unique tactile experiences using only 4 sensations
wet = change in temp and pressure
hot stove = high temp and high pain
Give an example of how senses can work together
Taste + smell from environment or food) = flavour
How is touch info organized in the brain
It is processed in the somatosensory cortex with areas of high sensitivity/fine detail (acuity) having the most space dedicated to them
What are the 4 major sensations that the skin detects?
-pressure
-temperature
-vibration
-pain
*Each has a different receptor
What is mirror-touch synesthesia?
When you feel touch on your body after seeing it on someone elses
What is the rubber hand illusion
You only let someone see a rubber hand
you touch both the rubber hand and their hand
eventually they feel sensation in their hand when you only touch the rubber hand
What is proprioception?
A sense of the body’s position in space.
It comes from sensory receptors in different areas of your body ex: joints and tendons.
Your sense of balance is an important part of proprioception.
What is your sense of balance controlled by?
Your vestibular system
-semicircular canals in your inner ear are filled with fluid and send signals to the area of your brain dedicated to vestibular function.
-vision feedback also helps
What is kinesthesis?
Perception of the movement of the limbs
What 2 types of perception allow us to coordinate our body movements in the world?
Proprioception
Kinesthesis
What is interoception?
Perception of internal organs (done by the insular cortex)
What are association areas?
Parts of the cortex where senses merge to enchance perception
How do blind ppl use the visual cortex?
to read braille!!
Born-blind ppl also use it to do auditory tasks so their auditory cortex can be used to locate sound in space
How do we tell the direction of a sound
-visually
-sounds arrive at ears at diff times
-head makes “sound shadow” so there is different loudness in diff ears
When do we tend to perceive sound the most accurately?
When the source is something we can see
What determines frequency and amplitude perception?
(Frequency theory and Place theory)
Frequency: Where the basilar membrane of the cilia is stimmed (wider end = low frequencies, high-mid = stiffer tip) and which part of the cochlea it is sent by (for mid-high only)
Amplitude: Based on frequency of stims
What are the limits of human frequency and amplitude perception
F: 20-20k Hz (times/sec)
A: Up to 120 db without damage
What is the point of colour and size constancy
Helps us to ensure that colours and sizes of objects appear the same in different lightings and at different distances ex: you don’t think your far away friend was shrunk and you don’t think your bedsheets turned gray in the lower lighting.
What is the ponzo illusion?
The one with the train track looking things where one line looks like its bigger (Hard to describe in words but you get it)
Why does your brain need to take your body and eye movements into account?
SO you can dissociate body movement from movement in the environment
Explain Gestalt Psychology
He has principles which are a set of rules the visual system uses to distinguish figures from a background ex: connectedness, proximity, closure, ect.
Some things challenge this system ex: WWF logo
What is Akinetopsia?
the inability to see motion.
happens with a damaged dorsal pathway
What is phiphenomena?
Apparent motion. (separate lights or images appear as one fluid movement)
What are the ventral and dorsal pathways
ventral = what. (in between occipital and temporal lobes)
dorsal = where (in parietal lobe)
What is the occipital lobe?
Primary visual cortex
What is prosopagnosia
Inability to recognize faces (me lol)
What normally happens when you see the face of someone you recognize?
Specific neural pathways are reactivated
What connects your eyes to your brain?
The optic nerve
Where does light hit your eyes?
In the back. (your retina)
a)When you see something in your central vision, where does the information from each eye go (brain hemisphere).
b)What about when something is on your right a bit?
c)What about when something is in your right peripheral?
a)Travels ispsilaterally
b) Both eyes send info to the left hemisphere
c) Right eye sends info to the left hemisphere
What are feature detectors?
Regions in our brain that determine the basic building blocks of vision ex: edges, angles, colours, movement.
Higher regions then allow us to represent whole objects
(Hierachial analysis)
What lobes are involved in hierachial analysis?
Occipital and sometimes temporal
If we only processed vision in the occipital lobe could we still perceive visual stimuli?
NO!
What is a large portion of our brain used for?
vision
What is pyschophysics?
The relationship between physical characteristics in our environment and our experience of them
What is absolute threshold?
minimum amount of stimulation needed to detect a stimulus 50% of the time
What is signal detection theory
A way to account for bias when measuring absolute threshold. It involves measuring when there is no stimulus to determine the false alarm rate.
What are some examples of sensory/perceptual adaptation
Nose-blindness
“First-sip feeling”
Light and Dark adaptation
Fixed visual stimuli would also disappear if our eyes weren’t constantly moving
Explain the difference between sensory and perceptual adaptation
Sensory: Constant stims will disappear after a while. This helps us to reduce noise in our environment and become more sensitive to changes in our surroundings
Perceptual: Decreased brain response due to unchanging stimuli
When might perception not equal reality?
-Colour constancy
-McGurk Effect
-Whole perception
-Sensory processing sensitiivty (some ppl process it more deeply)
Explain the differences between sensation, perception and transduction
Sensation: When a sensory organ detects a stimulus
Transduction: When the sensory info is turned to an electric signal
Perception: When the brain processes the electrical signals and determines what it “thinks” about the environment
