2. Vision Perception Flashcards
1
Q
What is sensation?
A
- passive process of bringing information from the outside world into the body and the brain
2
Q
What is perception?
A
- active process in brain of selecting, organising and interpreting the information brought into the brain by the senses
3
Q
How does sensation work?
A
- sense organ
- sense detected by receptor cells (take signals from the external environment)
- this turns into an electrical signal
- nerve conduit sends signal to the brain where it is processed
4
Q
What is the approach to study perception?
A
- gestalt psychology
- computational approach: feature representation
5
Q
What is gestalt psychology?
A
- gestalt is german for ‘form’ or ‘shape’
- paradigm that emerged in the late 19th century
- concerned with identifying laws which govern visual perception
6
Q
What do gestalt laws explain?
A
- how parts are arranged into forms and objects and perceived as a whole
7
Q
What is the law of pragnanz?
A
- simplicity
- we organise according to its simplest explanation
- may be seen as reductionist
8
Q
What are 3 other gestalt laws?
A
- common fate: elements that move together and tend to be grouped
- symmetry: elements that are symmetrical tend to be grouped together
- parallelism: elements that are parallel tend to be grouped together
9
Q
What is the visual pathway?
A
- visual input is recognised by the photoreceptors in the retina
- this is sent to the optic nerve
- then to the thalamus: where most sensory items arrive in the brain
- then to the primary visual cortex
- then to the higher visual cortices
10
Q
How is feature representation investigated?
A
- single neuron is recorder
- different visual stimuli are presented
- checked which ones elicit a response
11
Q
What is edge detection?
A
- determines differences between objects
12
Q
What are the two streams of visual processing?
A
- ventral stream
- dorsal stream
13
Q
What is the ventral stream?
A
- ventral to inferior temporal lobe
- processes shape, objects and language
14
Q
What is the dorsal stream?
A
- dorsal to the superior parietal lob e
- processes motion
15
Q
What does computational mean in visual perception?
A
- we reconstruct a visual scene by combining simpler elements
- built solely from visual inputs
16
Q
What does gestalt psychology mean in visual perception?
A
- combining elements in ways to gain a holistic understanding
- built using assumptions and knowledge about the world
17
Q
What is bottom up processing?
A
- processing the stimuli influences what is percieved
- data driven
18
Q
What is top down processing?
A
- background knowledge and expectations influence what is perceived
- expectation driven
19
Q
How do we resolve ambiguities?
A
- assumptions and cues are combined
