Psychology Class Notes - Sensation & Perception, Vision, Sleep

Reality, Sensation, and Perception
 Reality
o What we cannot sense/detect
 Only aware that they exist by knowing
o Light waves
o Sound waves
o Matter
o Microscopic organisms
o Air molecules
 Sensation
o Our senses detect
 Moment when the stimulus becomes represented by brain activity
o Detecting light waves
o Detecting sound waves
 Action potentials fired in ear
o Touching something
 Perception
o Interpreting what you are consciously experiencing
o Not an accurate representation of reality
 We ignore things that stay the same
o Detecting what color something is
o Recognizing faces, shapes, etc.
 If you cannot recognize specific faces, you have sensation but not
perception
 Fusiform face area specifically perceives faces
o Understanding words, etc.
o The Necker Cube
 The face of the cube can seem to change
 Visual illusion
 Perception changes, not the actual cube
 Sensation stays the same
o Context Effect
 Expectations fill in the blank
 Especially when reading
 We sense patterns
 Top-down processing
o Emotion and motivation
 Experiment by exposure to happy or sad music, hear homophone, then
write what they heard
 Dye vs die depending on mood
 Electroreception
o Detect electronic signals
o Ex: platypus

,  Magnetoreception
o Detect magnetic fields
o Ex: bird

Perceptual Set
 If you are used to interpreting something in a certain way, perceptual system is stuck in
that set
 Rat-Man ambiguous figure




o
 If you are shown faces before the test image, you will see man
 If you are shown animals before the test image, you will see rat

Visual Processing Pathway
 Vision is detecting certain wavelengths of light
o Wavelength and frequency are inversely proportional
o Gamma rays
o X rays
o UV rays
 Bees can see this
 Center of flowers reflect UV light, therefore bees can find where exactly
on the flower they should pollinate
o Visible spectrum (for humans)
 Colors
 400-700nm
 Higher wavelength is red; lower is blue
o IR waves
o Microwaves
o Radio waves
 Higher wavelength is AM; lower is FM
 How sight works
o Objects in the visual world
 Left visual field is to the left of one’s body
 Right visual field is to the right of one’s body
o Photoreceptors in the retina
 Right brain receives signals from left visual field
 And vice versa
 There is a small amount of right visual field that is detected by the left
eye, but it later gets transferred to the left brain
o Light travels down optic nerve
 Left and right optic nerves traverse at the optic chiasm

,  Here is where right signals from the left eye change to the other
optic tract to be sent to the left brain
o Lateral information does not cross over
o Medial information crosses over
 Don’t think of it as left eye goes to right brain, but that right brain
picks up the left visual field





o “What” Processing Stream
 Temporal lobe
 Primary visual cortex cells (in the brain) project axons to line cells to
recognize what is seen
 Line cells project axons to shape cells
 Shape cells come together to represent objects, faces, etc.
o Fusiform face region recognizes faces
o “Where” Processing Stream
 Parietal lobe
 Simultaneous with “What” Processing Stream
 Parallel distributive processing
 Where you are seeing the what
 Motion blindness
 Damage to parietal lobe
 Objects are recognizable, but movement is not
 If someone were walking, it is like they were teleporting
 Seeing color
o Photoreceptors in the rear of the retina