Lecture 2: perception Flashcards
What is perception?
The process by which agents (organism) interpret and organize sensation to produce a meaningful experience of the world
What are typical sensory modalities?
Light –> vision
Air vibrations –> Audition, echolocation
Physical pressure –> haptics (touch)
Chemicals–> taste and olfaction (smell)
Body Position–> Kinesthetics/proprioception
What is the extramission theory?
Rays of light emanating from the eye in combination with light in the world allow us to see. Salute pays homage to this theory
What is the intromission theory?
Visual perception is accomplished by rays of light reflected from objects into the eyes
The function of the human eye
Lens is used to focus. Muscles expand and contract to control the lens
Light is reflected into the eye and focused on the retina
Light stimulus the rod and cone receptors
Transduction of light into electricity
Your eyes are constantly moving (called siccads)
What are rods?
the most light sensitive photoreceptive cells in the retina (night vision): a. 100 times more sensitive than cones b. Information is received by a convergence or pooling from many rod cells resulting in a loss of visual activity; c.
Convergence of information makes peripheral vision sensitive to movement (seeing something vague out of the corner of your eyes
What are cones?
a. Correspond to short (blue) b. Medium )(green)
c. Long wavelengths (red); Works best in bright light; fewer cone cells exist for peripheral vision
What are the elements of depth perception?
Size, perspective, occlusion, texture, shading, saturation, focus on multiple things
What is the dorsal stream?
“Where” pathway; associated with motion, representation of object locations and control of the eyes, and arms especially when visual information is used to guide saccades or reaching
What is the ventral stream?
“What” pathway, associated with form recognition and object representation. It is also associated with storage of long term memory.
What is the pandemonium model of perception?
Little demons (something that operates on its own) telling demons at the next level what they are detecting.
What is template matching perception?
Template of what something would look like and then look for overlap of pixels in the real world. this is Outdated
What is the process of the neural network perception?
Each pixel corresponds to and activates something in the input layer. Spreading activation to the next layer and then hidden does the same until you get an output
How are sound waves collected?
By the pinna and funnels sound into the ear canal which hits the membrane
How is vertigo caused?
by the movement of “rocks” in your ear
How does audition work?
Acoustical energy (sound waves) vibrate the eardrum (in air) or bones (underwater or through your own body as when you hear your voice). Localization is done by examining the differences between the sounds in the two ears
What is echolocation?
Bio sonar: send out sound, determine spatial information from echo. Examples: Bats, toothed whales, dolphins and two kinds of birds. Humans: the boy who sees without eyes
What is haptics?
Critical for manipulation of objects, particularly in combination with proprioception. Sensors are in the skin
What is olfaction?
Smell, Detection of chemicals- no clear energy continuum as there is for light and sound waves. Some similar chemicals smell different some different chemicals smell the same. Much of what we experience as taste is actually smell (This is why food tends to taste bland when you have a stuffy nose)
How is smell used for animal communication?
Territory, Fertility, Anti pheromone traces. Why do male dogs raise their leg to pee? Maximize height
What is gustation?
Chemical receptors in taste buds last for a week or two then wear out. The tongue detects flavours such as salty, sour, bitter, umami and sweet. Pain receptors react to spicy food
What does the experience of food involve?
The experience of food is very complex, involving feel, temperature, taste, smell and pain
What sensory modalities are considered to be active perception?
Haptics (touch) and vision
