14- Sensation + Perception, taste and vision Flashcards
Absolute threshold
the minimum amount of stimulus energy needed for an observer to perceive a stimulus, an ideal conditions, 50% of the time.
Absolute threshold for the sense, hearing.
the ticking of a watch 6m away
Absolute threshold for the sense, smell.
one drop of perfume in a large house
Absolute threshold for the sense, taste.
one teaspoon of sugar dissolved in 10 L of water
Absolute threshold for the sense, touch.
the wing of a fly falling on the cheek from a height of 1cm.
Absolute threshold for the sense, vision.
the flame of a candle 50km away on a dark, clear night.
The six stages of sensation and perception
- Reception
- Transduction
- Transmission
- Selection
- Organisation
- Interpretationu8
Sensation in vision: Reception
- Light enters the eye through the cornea
- Passes through the pupil
- The lens focuses the light on the retina
Sensation in vision: Transduction
- The light energy is converted by the rods and cones into electrochemical nerve impulses.
- This allows the visual information to travel along the fibres of the optic nerve to the brain.
Sensation in vision: Transmission
- The rods and cones is to send the nerve impulses along the optic nerve to the primary visual cortex in the occipital lobes
- This is where specialised receptor cells respond as the process of visual perception continues.
Perception in vision: selection
-The image is broken up by specialised cells called feature detectors.
Perception in vision: organisation
-Our visual cortex in the brain recognises information so that we can make sense of it.
-we do this by using certain visual perception principles,
>Perceptual constancies
> Gestalt principles
> depth cues
-after the image is re-assembled is travels along 2 pathways
1, to the temporal lobe, to identify the object
2, to the parietal lobe, to judge where the object is in space.
Perception in vision: interpretation
-This is where the visual stimulus (object) is given meaning.
-The temporal lobes identify what the object is by comparing incoming information with information already stored in memory.
eg, past experiences, motives, values and context.
What is the wavelengths of the electromagnetic spectrum for light energy to be visible to the human eye.
Wavelengths of between 360-760 form the visible spectrum.
What photoreceptors are contained in the retina of the eye?
Rods and cones
Rods
-125,000,000 in each eye
-Responsible for vision in
>low light
>Peripheral vision
-They have low visual acuity (cant register detail)
-Only register in Black and White
-Most sensitive to light of approximately 500nm wavelength
Cones
-6,500,000 in each eye
-Responsible for vision of
>detail
>colour (black and white vision in daylight)
-They require high levels of light to enable them to respond
what part of the brain is responsible for taste
gustatory cortex
what part of the brain is responsible for vision
visual cortex
how many taste buds are located in the mouth and throat
10,000
each taste bud contains how many taste receptor cells?
50-150
Five primary taste
Bitter- back Sweet-tip Sour -forward sides Salty-back sides Unami-middle
Sensation in Taste: Reception
chemicals are dissolved in saliva during the process of chewing
Sensation in taste: Transduction
The chemical energy is converted by receptor cells on the taste buds into electrochemical nerve impulses
