chapter 14

Question 1

what is the absolute threshold

Answer 1

is the minimum amount of physical energy needed for an observer to perceive visual stimulus in ideal conditions, 50 percent of the time

Question 2

absolute threshold for hearing

Answer 2

the ticking of a watch six meters away

Question 3

AT for smell

Answer 3

one drop of perfume in a large house

Question 4

AT for taste

Answer 4

one teaspoon of sugar dissolved in 10L of water

Question 5

AT for touch

Answer 5

the wing of a fly falling on the cheek from a height of one cm

Question 6

AT for vision

Answer 6

the flame of a candle 50km away on a dark clear night

Question 7

what are the five tastes

Answer 7

bitter (back of tongue)
salty (sides of tongue)
sour 
sweet (top of tongue)
unami (middle of tongue)

Question 8

how many rods are there in the eye

Answer 8

125,000,000

Question 9

location and responsibility of rods

Answer 9

located at the edges of the retina
they’re responsible for vision in low light situations and for peripheral vision
black and white

Question 10

requirements of rods

Answer 10

registers only in black and white

cannot register detail

Question 11

number of cones in the eye

Answer 11

65,00,000

Question 12

location and responsibility of cones

Answer 12

located in the middle of the retina

responsible for colour vision

Question 13

requirements of cones

Answer 13

requires high levels of light to be able to respond

Question 14

Sensation process in vision

Reception, transduction and transmission

Answer 14

Reception
Light enters eye through the cornea and then the pupil. The lens focuses the light on the retina where the rods and cons are

Transduction
Electromagnetic energy is converted by rods and cones into electrochemical nerve impulse
This allows visual info to travel along the fibres of the optic nerve to the brain

Transmission
Rods and cones send nerve impulses along the optic nerve to the primary visual cortex, where receptor cells respond and visual perception continues

Question 15

Perception process in vision

Selection. Organisation. Interpretation

Answer 15

Selection - image broken up by feature detectors and they respond to lines of a certain length , angle or movement

Organisation -
The brain reorganised info so we can make sense of it using depth cues, Constancies and principles
Image then travels through the temporal and parietal lobes where it is made sense of

Interpretation: visual stimulus is given meaning
Object is identified by comparing incoming info to memory

Question 16

What are the six stages of the process of sensation through to perception

Answer 16

Reception
Transduction
Transmission
Selection
Organisation
Interpretation

Question 17

process of sensation in taste

Answer 17

reception: chemicals are dissolved in saliva through chewing
transduction: chemical energy is converted by the receptor cells on the tastebuds to the electrochemical nerve impulse
transmission: from the tastebuds the nerve impulses travel through the thalamus to the primary gustatory cortex low in the parietal lobe

Question 18

process of perception in taste

Answer 18

the brain recognises the sensation of a mixture of the five primary tastes and combines this with the smell, colour, and texture of the food to perceive the flavour of what we eat

Question 19

the visible light spectrum

Answer 19

light entering the eye is an important part of our ability to receive and interpret a visual stimulus
the light energy must be within the visible parts of the electromagnetic spectrum. this is between wavelengths of 360-760 nanometers