Perception Flashcards
transduction
making meaning out of sensory input/stimuli
The experience resulting from stimulation of the senses.
perception
perception seems automatic and effortless but involved active and constructive processes, drawing on higher level _____________ (2) to resolve the many ambiguities in what we perceive.
cognitive abilities
Inverse projection problem
the task of determining the object responsible for a particular image on the retina
- which shape/image on the retina goes with which object in the environment?
- any 2D image formed on the retina could be formed by many 3D objects in the environment
BRAIN HAS TO FIGURE OUT THE TRUE FORM OF AN OBJECT BASED ON THE 2D image the retina is getting
- think about those catfish sims - we think we’ll know what they look like straight on based on the harmony of features but then you turn it to the side and well…
perception difficulties (list 3):
objects can be blurred, hidden, obscured, things are uncertain
-> perspective, lighting, angles -> this is why perception is so complex because we have to figure out all of those to understand the TRUE form of what we’re seeing
Viewpoint invariance
a cognitive mechanism that allows us to recognize an object as equivalent or the same from different perspectives (perspective changes depending on orientation, lighting, etc.)
Direction perception theories focus on what type of processing? Which is:
bottom up -> observe first, THEN transduce/get meaning
Direct Perception Theory:
- perception comes from getting pieces of stimuli in the environment, and then putting them together like a puzzle so recognition can ocur
Construction perception theories involve which type of processing? This type of processing is:
Top-down processing - higher level cognition focused on constructing perceptions using information based on prior expectations
- eg: if you read the word “Laurel” right before hearing the Yanny/Laurel audio, you’ll hear “Laurel” but if you read “Xanny” first you might hear that one instead
Bottom up processing with example
perceiving something starts from the senses and THEN making a conclusion from that
- eg: -> You see your friend slap you -> nerve receptors activated too harshly -> conclusion: feeling pain
Top-down processing with example:
Perception starts with the brain, knowledge, experience, and expectations which SHAPES what is perceived.
Eg: if you’re a beginner magician watching a magic trick, if you want to figure out how the trick works, you’ll use your prior magician knowledge to analyze the trick closely which will affect how well the trick works on you/affects you/surprises you
In practice, both bottom-up and top-down mechanisms tend to be involved in more perceptional experiences, but what is the main difference between them put simply?
Bottom-up - what you see
Vs.
Top-down - what you expect
The phrase “you see what you wanna see” is related to which type of processing because it’s based on ___________ (1).
top-down
expectations
Audiovisual speech perception
The idea that you don’t only perceive what you’re hearing when transducing speech, but the way you also take into account the way the mouth moves (visually) to get a hint to what the sound could be.
The McGurk Effect experiment in which the audio “Ba” is played with a clip of a person making the shape for “Fa, making it hard to distinguish whether or not you’re hearing Ba or Fa is an example of _____________ (3).
audiovisual speech perception
the visual input changes the perception of the sound:
overall this aligns with the idea that:
audiovisual speech perception.
sensory info converges
eg: if you eat something crunchy WITHOUT hearing the crunch, this may affect how it feels and tastes in your mouth
Speech segmentation
when we divide the acoustic signal/sound we hear, into individual words that we can understand
if you’re native to a language, even if you’re hearing someone speak with little to no breaks in between words, you’ll still understand do to your ability of ____________ (2).
However, if you’re not native, you won’t understand the individual words, or where one word starts and begin and it’ll sound like a continuous stream of sound because you cannot do _____________ for this language (same answer for both blanks).
speech segmentation
Helmholtz’s Theory of Unconscious Inference
some of our perceptions are a result of unconscious assumptions and inferences we make based on prior knowledge and personal history
- classic top-down thinking -> letting expectations and what we’ve experienced affect what we perceive
Likelihood principle
we perceive the world in the way that’s most likely based on our past experiences (more top-down)
structuralism
breaking down psychological processes - eg: what does each brain structure do on it’s own to achieve this one structure
- think of how a chemist would break down a compound into it’s constituent (separate) elements
Gestalt
school of thought that rejected the structuralist approach - the meaning isn’t inherent to the blocks, it’s HOW the blocks are put together to make the BIG PICTURE - more about grouping
Law of perceptual organization (general definition)
Perception is a product of the mind GROUPING patterns according to similarity, proximity, etc.
Phi phenomenon
moving pictures - still images are seen as being in continuous motion when
animation
phi phenomenon comes from which school of thought and why
gestalt because in this phenomenon you’re perceiving the images to be moving because you’re not looking at only one constituent image but the effect they create when shown one after another
the reductionist school of thought is similar to the ________ one
structuralist - piece by piece rather than looking at the whole
Gestalt Principles of Perceptual Organization (5)
- Phi phenomenon
- principle of good continuation
- Law of praganz
- Principle of proximity
- Principle of similarity
Principle of good continuation
Lines tend to be seen/predicted as following the SMOOTHEST path possible - straight lines or curved lines; no sharp turns or whatever
Law of pragnanz
every stimulus pattern is seen so the resulting structure is as SIMPLE AS POSSIBLE
We like to try to simplify patterns in our head - think Olympic rings -> they’re perceived as 5 overlapping rings, not 9 pieces
principle of proximity
close together gets grouped together
principle of similarity
similar things get grouped together
physical regularities
patterns in the environment that allow us to develop this
Oblique effect
vertical and horizontal lines are perceived more easily than lines of any other orientation
why oblique effect?
more horizontal and vertical lines in environment -> we probably developed feature detectors for them since they’re the most common -> more easy to detect
Light-from-above assumption
the way we assume light is from above because of the sun
- shadow placement changes the way we perceive things
Semantic regularities
the characteristics typically associated with different types of scenes -> eg: fork in kitchen lol
- what does this scene usually involve?
semantic regularities are heavily tied to ____________ (2).
scene schemas
scene schema
the knowledge of what a given scene ordinarily contains
Semantic regularities and scene schemas would be examples of ___________ processing.
top-down processing
Bayesian inference - the estimates of a probability of an outcome are influenced by TWO FACTORS
- Prior probability (initial belief about probability of an outcome - top down processing; what you expect from this)
- Likelihood of given outcome - what do the stats says about how common this outcome is?
How does the Bayesian inference relate to Helmholtz’ theory of unconscious inference?
- using prior knowledge and experiences to put expectations and predictions on an outcome
- top-bottom processing
4 approaches to perception:
Which one stands out -
- Helmholtz’s unconscious inference
- Regularities in the environment
- Bayesian Inference
- all top-bottom processing^^^
- Gestalt laws of perceptual organization
- built in mechanisms ^
Experience-dependent plasticity
the idea that some neurons or feature detectors are made and tuned to the most common stimuli in the environment hence the presence of the oblique effect
- brain (neurons) change to what’s most common in environment (experience-dependent)
the expertise hypothesis
Going beyond experience-dependent plasticity -> some feature detectors (in the FFA) might become tuned to respond to the processing of any stimuli we’ve developed PERCEPTUAL EXPERTISE WITH
definition and example of the expertise hypothesis:
if we’re an expert in a subject some of our feature detectors areas go above and beyond and notice things normal people wouldn’t
- for example as an artist, it’s easier for me to notice where I could improve in the elements of art, whereas a non-artist might just look at it and be like thats nice
- or when i look at my friends art i notice all the little details and techniques they incorporated whereas a non-artist would just be like “that’s nice!”
Dorsal stream vs. Ventral stream
dorsal - where
ventral - what
Lesioning is also known as:
ablation
describe the process of lesioning in animals:
- Animal trained to do indicate perceptual capacities
- specific part of the brain REMOVED, DESTROYED, LESIONED
- animal retrained to determine what perceptual abilities remain
- results reveal which parts of the brain serve which perceptual functions and behaviours
Object discrimination problem - which stream? What’s involved?
ventral - identifying WHAT - monkey has to look for food UNDER an object
Landmark discrimination problem
dorsal stream - where - monkey look for food NEXT to object
Experimental manipulation
lesioning in monkeys to figure out if dorsal was parietal or temporal lobe
what lobe of the brain and what experiment is the ventral pathway associated with
temporal
object discrimination task
“What”
what lobe of the brain and what experiment is the where pathway or dorsal stream associated with
parietal lobe
Landmark discrimination task
Double dissociations
two regions of the brain that distinctly serve different functions - so damaging what part won’t effect the other and vice part
What pathway is associated with perception
Where pathway/dorsal stream
action pathway vs. perception pathway
what vs. where
