Chapter 4 sensation and perception

Question 1

What are the 3 types of light waves?

Answer 1

Amplitude, wavelength and purity

Question 2

How is light registered?

Answer 2

receptors in the eye

Question 3

What do the key eye structures include?

Answer 3

Lens - focuses light rays
Pupil - regulates the amount of light passing to the rear of the eye
Retina - neural tissue lining the inside back surface of the eye
optic disk - a hole in the retina that corresponds to the blind spot
Fovea - tiny spot in the center of the retina where visual activity is greatest.

Question 4

What are the 3 visual receptors in the retina?

Answer 4

Rods- play a key role in night and peripheral vision
cones - day and color vision
receptive fields - collections of rods and cones that funnel signals to the specific visual cells in the retina or brain.

Question 5

What are the visual pathways and processing?

Answer 5

main visual pathway - projects through the thalamus, signals are processed and distributed to the occipital lobe
second visual pathway - handles coordination of visual input with other sensory input.
primary visual cortex - the occipital lobe handles initial processing of the visual input
feature detectors - neurons that respond selectively to specific features of complex stimuli.

Question 6

After processing in the primary visual cortex, what visual input is routed to?

Answer 6

other cortical areas along the where pathways (dorsal stream) and the what pathway (ventral stream)

Question 7

What are the color perceptions?

Answer 7

subtractive color mixing - works by removing some wavelengths of light, leaving less light
additive color mixing - works by putting more light in the mixture than anyone light.
Trichromatic theory - holds that the eye has three groups of receptors sensitive to wavelengths associated with red, green, and blue.
Opponent process theory - holds that receptors make antagonistic responses to three pairs of colors
conclusion - the evidence suggests that both theories are necessary to explain color perception.

Question 8

What are form perceptions?

Answer 8

• the same visual input can result in very different perceptions
• form perception is selective, as the phenomenon of inattentional blindness demonstrates
• some aspects of form perception depend on feature analysis, which involves detecting specific elements and assembling them into complex forms.

Question 9

What is depth perception?

Answer 9

Binocular cues - clues about distance based on differing views of the two eyes
Retinal disparity - refers to the right and left eye seeing slightly different views of objects.
Monocular cues - clues about distance based on the image in either eye alone.
Pictorial cues - are monocular cues that can be given in a flat picture such as linear perspective, texture gradients, relative size etc.

Question 10

What are visual illusions?

Answer 10

is a discrepancy between the appearance of a visual stimulus and its physical reality

Question 11

What is the Muller-Lyer, Ponzo and the moon illusion show ?

Answer 11

perceptual hypotheses can be wrong and the perception is not a simple reflection of objective reality

Question 12

What are the Auditory system?

Answer 12

Amplitude - loudness, wavelength - pitch and purity -timbre

Question 13

What are the key ear structures and there purpose?

Answer 13

Pinna - external ears sound collecting cone
eardrum - taut membrane, vibrates in response to sound waves
Ossicles - three tiny bones in the middle ear that convert the eardrums vibrations
Cochlea - fluid-filled coiled tunnel that houses the inner ears neural tissue.
Basilar membrane - hold the hair cells that serve auditory receptors

Question 14

What are the pitch preceptors?

Answer 14

Place theory - perception of pitch depends on the portion of the basilar membrane vibrated.
Frequency theory - perception of pitch depends on the basilar membrane’s rate of vibration
Conclusion - evidence suggests that both theories are needed to explain pitch perception

Question 15

What are facts about smell?

Answer 15

• olfactory cilia absorbs chemicals in the nose and trigger neural impulses.
• olfactory receptors have a short life and are constantly replaced
• smell is not routed in the thalamus.

Question 16

What are some facts about the taste receptors?

Answer 16

-taste cells absorb chemicals in saliva and trigger neural impulses routed through the thalamus.
-sensitive to four basic tastes - sweet, sour, bitter, salty and umami.
-supertasters have more taste buds and sensitive to bitter and sweet things.
-women are more likely to have supertasters
non tasters are more susceptible to lure of sweets high fat food and alcohol.

Question 17

Some fact about touch

Answer 17

• respond to pressure, temperature and pain
  -pain signals travel along a fast pathway
  -gate control can block pain receptors in the spinal cord.
  endorphins can cause you to feel less pain
  -glial cells contribute to the modulation of chronic pain.