CHAPTER 3: VISUAL PERCEPTION PART 3
What does the "WHAT-HOW" hypothesis describe?
It describes deficits in recognizing objects and in reaching for them
What does the "WHAT" hypothesis focus on?
Identifying and defining the nature or essence of an object
What does the "HOW" hypothesis relate to?
The mechanisms involved in the functioning of an entity
What is AGNOSIA?
Trouble perceiving sensory information
What CAUSES AGNOSIAS?
Damage to the border of the temporal and occipital lobes
What is a CHARACTERISTIC of SIMULTAGNOSIA?
Inability to focus on more than one object at a time
What is PROSOPAGNOSIA?
Inability to recognize faces
What is IMPAIRED in INDIVIDUALS WITH PROSOPAGNOSIA?
Ability to identify familiar faces
What do INDIVIDUALS WITH PROSOPAGNOSIA STRUGGLE with despite being able to see facial features?
Processing the overall configuration that makes a face recognizable
What is APPERCEPTIVE PROSOPAGNOSIA?
Inability to recognize facial expressions or non-verbal cues
What is ASSOCIATIVE PROSOPAGNOSIA?
Inability to recognize familiar faces despite familiarity
What is ATAXIA?
A perceptual deficit related to the "how" pathway
What is OPTIC ATAXIA?
Impaired ability to use the visual system to guide movement
What CHARACTERIZES OPTIC ATAXIA?
Example: When trying to grab a coffee cup, a person with this condition may struggle to reach it accurately despite seeing it clearly.
Difficulty guiding hand movements based on visual input
Which pathway is RESPONSIBLE for EXECUTING IMMEDIATE MOVEMENTS?
Dorsal-stream processing
What happens in SIMULTAGNOSIA?
Inability to focus on multiple objects simultaneously
What can CAUSE COLOR PERCEPTION DEFICITS apart from GENETIC FACTORS?
Lesions to the ventromedial occipital and temporal lobes
What is ROD MONOCHROMACY (ACHROMACY)?
Complete color blindness, seeing only shades of gray
What is DICHROMACY?
Having two functioning color-detecting mechanisms
What is PROTANOPIA?
Extreme form of red-green color blindness
What is DEUTERANOPIA
Trouble seeing greens with symptoms similar to protanopia
What is TRITANOPIA?
Confusion of blues and greens, with yellows appearing light red
What is DICHROMACY?
Having two different cone photopigments
What is MONOCHROMACY?
Seeing in black and white only
What is TRICHROMACY?
Having three cone photopigments responding to different wavelengths
What area is AFFECTED IN COLOR PERCEPTION DEFICITS besides GENETIC CAUSES?
Ventromedial occipital and temporal lobes
What CHARACTERIZES individuals with ROD MONOCHROMACY?
Seeing only shades of gray
What is VISUAL-OBJECT AGNOSIA?
Example: A person can see a chair but does not recognize it as something they can sit on.
Seeing objects without understanding their meaning
A person cannot identify if someone is happy or sad by looking at their face. This is an example of:
Apperceptive prosopagnosia
A person sees a friend but cannot identify who they are, even though they know them well.
Associative prosopagnosia