Laura Heijnen – Perception
Problem 1. A Keen Eye
A.
Blake, & Sekuler (2006) – Perception – Chapter 2: The Human Eye
Goldstein (2010) – Sensation and perception – Chapter 3: Introduction to Vision
What is the structure of the eye (anatomy), and what are the functions
(physiology)?
Visual system:
- Eyes: capture light + convert it into neural messages.
- Visual pathways: modify + transmit messages from eye to brain.
- Visual centres of the brain: interpret messages in ways useful for guiding behaviour.
Designing the organ of vision
Diversity of eyes in nature
- Vision is distance sense: allows to detect + recognise objects without having to come
close to objects (also hearing).
- Many species have same eye design as humans, but also different ones: compound
eyes (multiple small lenses), photosensitive pigment = light-sensitive spots all for
primary goal organism, possibly due to natural selection.
Place of eyes
- Naturally outgrowth of brain head, near brain.
- Frontal or lateral (sideways) position frontal (predatory animals) improves depth
perception, but lateral (prey) makes it possible to take in more of visual world in one
time.
Ability to move
- Compensation for relatively narrow field of vision (frontal rather than lateral eyes).
- Large eyes, barely fitting into sockets = harder to move eyes (e.g., owls).
- Humans looking extreme left to extreme right takes only 1/5th of second = rapidly.
- Also moving with accuracy: precision to what to look at. Possible because of
extraocular muscles.
- Each muscle connected at one end to an immovable structure (= eye socket of skull),
other end is free to move (= eye ball). Extraocular muscle contracts pulls on eyeball
+ moves it.
1
Problem 1. A Keen Eye
A.
Blake, & Sekuler (2006) – Perception – Chapter 2: The Human Eye
Goldstein (2010) – Sensation and perception – Chapter 3: Introduction to Vision
What is the structure of the eye (anatomy), and what are the functions
(physiology)?
Visual system:
- Eyes: capture light + convert it into neural messages.
- Visual pathways: modify + transmit messages from eye to brain.
- Visual centres of the brain: interpret messages in ways useful for guiding behaviour.
Designing the organ of vision
Diversity of eyes in nature
- Vision is distance sense: allows to detect + recognise objects without having to come
close to objects (also hearing).
- Many species have same eye design as humans, but also different ones: compound
eyes (multiple small lenses), photosensitive pigment = light-sensitive spots all for
primary goal organism, possibly due to natural selection.
Place of eyes
- Naturally outgrowth of brain head, near brain.
- Frontal or lateral (sideways) position frontal (predatory animals) improves depth
perception, but lateral (prey) makes it possible to take in more of visual world in one
time.
Ability to move
- Compensation for relatively narrow field of vision (frontal rather than lateral eyes).
- Large eyes, barely fitting into sockets = harder to move eyes (e.g., owls).
- Humans looking extreme left to extreme right takes only 1/5th of second = rapidly.
- Also moving with accuracy: precision to what to look at. Possible because of
extraocular muscles.
- Each muscle connected at one end to an immovable structure (= eye socket of skull),
other end is free to move (= eye ball). Extraocular muscle contracts pulls on eyeball
+ moves it.
1
