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.
Split brain patients
In extreme cases of epilepsy they severed the corpus callosum. This creates to separate consciousness, which sometimes conflict with each other. This is when hemispheres become further specialized.
Extreme hydrocephalus
This happens when ventricles expand, squeezing and destroying brain tissue.
- In an extreme case a 44 year old man had lost 75% of brain tissue but was living a normal life. He developed extreme plasticity which is assumed to be possible because the loss of brain tissue took time (was gradual).
What is the hard problem?
We can gather information about how the brain and other processes work but that doesn’t tell us anything about experience.
What is dualism and who proposed it?
Dualism was proposed by Descartes and it proposed that mind and body are fundamentally distinct and that they can exist without the other.
What is idealism?
Idealism suggests that the mind is fundamental and that the physical world is created by experience.
What is materialism/physicalism?
This is the most popular and influential theory, although it’s losing ground.
Suggests that physical things are the fundamental reality. The mind can be reduced to physical terms and it’s ultimately caused by the brain.
What is Dual Aspect Monism?
This theory is gaining grounds.
Proposes that the mind and body are real and exist in all things.
Steps of perception: distal, proximal and percept stimulus
Distal stimulus –> actual object
Proximal Stimulus –> light hitting your eye
Percept –> representation of the environment in your mind
Light from above assumption
We assume that the light comes from above, and interpret a shadow size and direction to determine depth, orientation and distance.
Greebles experiment
- Exposure to odd looking Greebles.
- Participants trained to name different Greebles.
- After training Fusiform Face Area activated more than before training.
Perception and action
- Work together.
- Movement helps us disambiguate objects.
Two visual pathways
Both start in the primary visual cortex (occipital lobe).
The dorsal stream (where pathway) moves up through the parietal lobe –> location and movement
The ventral stream (what pathway) moves down to the temporal lobe –> processes object features
