Quiz 3 (Consciousness and Perception) Flashcards
What is perception?
Perception is recognizing a stimulus with one of the senses.
- Complex ongoing process in which bottom up and top down processes are working together.
What is bottom up perception?
- Old way of seeing perception.
- Suggests we perceive small stimulus and then put pieces together through stages of processing to end up with complex.
- Driven by external stimulus.
- No prior knowledge needed.
- There are ambiguous inputs were different states of the world could produce same perceptual input.
What is top down processing?
- Newer way of seeing perception.
- We have to access our knowledge and experience to evaluate a stimulus and decide which is the most likely interpretation of it (disambiguate it).
- We often do unconscious inferences when the stimulus is ambiguous.
- Studied by Gestalt psychologists
What is the inverse projection problem?
An infinite number of distal stimuli could lead to any one percept.
View point invariance
We’re able to recognize incomplete or obscured object (object occlusion). We have the ability to recognize objects from different viewpoints.
- movement helps perceive things more accurately than static.
Direct perception theories
- Bottom up processing
- We construct perception based on what we see
- You increase the complexity as you go from posterior to anterior
Constructive perception theories
- Top down processing
- Perception is constructed by interpretation based on prior knowledge
- Likelihood principle –> which alternative is moste probable
What are some of the laws proposed by Gestalt psychologists?
- Law of good continuation –> perceive continuous fragments of an object as continuous. Eg., assume coiled rope is continuous.
- Law of Pragnaz (simplicity or good figure) –> assume that pattern seen is caused by most simple observation.
- Law of similarity –> similar things appear grouped together.
What is the Oblique effect?
It’s easier for us to perceive vertical and horizontal lines as they are more common and we have more specialized neurons to do so (experience dependent plasicity).
Scene and scene schema
Scene–> different scenarios where you can find yourself. Eg., sports scene, classroom scene, etc
Scene schema–> what you expect to see at a given scene.
Semantic regularities
- When you view a scene you naturally categorize it by meaning, or what you expect to occur within it.
- How knowledge of conversation helps in disambiguating words
- Top down to disambiguate words
How can pain be affected by top down perception?
- Distraction, attention and expectations can affect how we experience pain.
- Placebo effect –> our expectations of pain change how strongly we experience it.
What is the Bayesian inference?
There are 2 important things that affect the probability of the outcome.
1) Prior probability (base rates) –> how likely are things to happen in general.
2) Likelihood –> Current evidence and how consistent it is with the outcome
You adjust current evidence by the base rates.
What is blindsight?
Blindsight is a very rare phenomenon in which people have damage to their primary visual cortex and have a blind field in specific regions. Some patients claim to have complete blindness in these fields.
Despite blind field, some people can discriminate stimulus location, orientation and other information for stimulus presented in blind spot, despite them claiming that they can’t see anything.
- Suggests that partially intact unconscious vision remains –> example of access consciousness without phenomenal consciousness.
What is negelct?
Neglect is a much more common phenomenon in which there is damage to the inferior parietal lobe. Patients ignore contralateral visual side. They don’t understand that they have a problem, to them the side they see is the whole picture.
