Class notes
COGNITION Visual perception and object recognition
- Course
- Institution
- Book
Lecture notes to get a first
[Show more]
Connected book
Book Title:
Author(s):
- Edition:
- ISBN:
- Edition:
More summaries for
-
Cognitive Psychology and Cognitive Disorders - CLPS11052 - Lecture notes, reading notes, essays, exam preparation
-
COGNITION Module introduction
-
COGNITION Face perception
Seller
Follow
chilllax
Content preview
Week 2: Visual perception and object recognition19 September 2022 20:47
VIDEO 1: KEY CONCEPTS OF OBJECT RECOGNITION LIVE-SEMINAR 22.09.22
READING chapter2 55-64
How we process visual stimulus Marr’s three levels of analysing a cognitive function
•3 different types of analysis of an information-processing system
• Computational – TASK ANALYSIS
• Algorithmic – WHICH PROCESSES & OPERATIONS ARE NEEDED
• Implementational – THE PHYSICAL STRUCTURE THAT DOES THE WORK.
STAGES IN VISUAL PERCEPTION
How different part of the cortex become progressively complexed
The journey of visual information
Evidence for stages in visual processing: visual agnosia patient
HJA Humphreys & Riddoch (1987)
61 year old man
Post-op stroke
THE "WHAT" and "WHERE/HOW" PATHWAYS
Impaired reading, face and object recognition
Dorsal stream:
Ventral stream:
• "How" pathway Loss of colour vision
• "what" pathway
• Vision-for-action
• Vision-for-perception Visual field defect but normal visual acuity
• Egocentric (body-centred) coding
Normal discrimination of length, orientation and position
EVIDENCE FROM PATIENTS: Stereoscopic vision intact
Optic ataxia (dorsal damage)
==> Could take in information but can't identify objects, places and faces!
Visual form agnosia (patient DF)
BUT double dissociation not robust He CAN draw objects from memory!! But couldn’t see their meaning
•HJA can describe objects from memory: Has intact knowledge of object appearances and
Inferior temporal cortex functions
•HJA can copy drawings of objects he can’t recognise
The seperation of different streams is not as distinguished as thought before.
Interwined, operating together
WHERE IS HJA'S PROBLEM?
EVALUATION PERCEPTION-ACTION MODEL
• Very influential theoretical approach
• TWO systems less independent and more interactive than assumed
• Separate dorsal streams: Herpes Simplex Patients
○ Dorso-dorsal system – grasp object fast Warrington and Shallice (1984)
○ Ventro-dorsal system – memorised object knowledge to use objects Normal visual perception
appropriately
Problems with recognising or describing living things
Read: cap 2 pp 55-64 Can name objects from verbal/functional description (“what animal is used to obtain ham?”)…
VIDEO 2: THEORIES VISUAL PERCEPTION
...but not from a visual description (“an insect with broad, coloured ornate wings”)
Problems with concrete words but not abstract ones
MODEL OF OBJECT RECOGNITION
Navon (1977) stimuli
Where is the probem in HERPES SIMPLEX?
Semantic agnosia
Warrington (1975)
Patient AB (dementia)
Verbal IQ = 122, normal acuity, matching objects across views
Couldn’t name common objects (0/12), pictures of objects (11/20) or photos of faces (2/15)
Notes Page 1
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller chilllax. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.13. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67232 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now