L2: Perception Flashcards
What is Sensation
It is a passive process of bringing information from the outside world and the translation of this information into signals the brain can process.
What is Perception
It is the active organisation and interpretation of sensory information into something meaningful.
What are some challenges to perceptual organisation?
- Deciding which parts of the environment go together and which belong to different objects
- Recognising an object over a wide range of viewing distances and orientations
- Objects vary greatly in their visual properties (ie. color, size, shape)
- Figuring out which part of the visual field is figure (having a distinct form) and which is the ground (lacking a distinct form) -> figure-ground segregation
2 ways to recognise patterns
- Template
- Features
How does Template Theory work?
Templates (whole percepts) are stored in long-term memory. A pattern is recognised when its template is matched to the stimulus input.
How does Feature Theory work?
Patterns consist of specific features. We recognise a pattern if it contains specific features.
What is the Word Superiority Effect?
Letters are easier to identify when they are part of a real word than part of a nonword. Features are easier to process when they are part of a meaningful object.
What is Recognition-By-Components based off?
Biederman suggested that all objects consist of basic shapes / components called geons. There are around 36 different geons.
What is the claim of Recognition-By-Components?
Claims that we can recognise an object regardless of viewpoint, as long as all geons are visible.
What is visual agnosia?
The inability to recognise visual objects despite information reaching visual cortex.
What is agnosia?
The loss of ability in interpreting sensory stimuli
2 types of agnosia
- Apperceptive agnosia: Object recognition is impaired due to deficits in perceptual processing
- Associative agnosia: Perception is fine, but there is difficulty retrieving knowledge about objects from long-term memory.
How are faces processed differently than objects?
Faces are processed more holistically, as a unified and integrated whole, rather than a collection of individual parts.
What is prosopagnosia?
Face blindness, individuals with prosopagnosia can recognise objects, but have great difficulty recognising faces. Suggests that object and face recognition tap separate systems and brain areas.
Explain vision for action and perception
Visual system seems to be organised into 2 functionally specialised processing pathways - there’s a dorsal pathway for action and ventral pathway for perception
