Lecture 4: Sensation and perception Flashcards
What is sensation?
- Physical process
- We “look” with our eyes
- raw input from environment
- Involves sensory organs
- respond to external stimuli is gathering the info from the environment via your senses
- hearing and taste
- hearing someone’s voice
- seeing lecture on the screen
- tactile, how the seat feels
- our window to the world
what is perception?
- Psychological process
- We “see” with our brain
- psychological process by which we make sense of all the stimuli received from environment
- We perceive the burning toast
- or the voice shouting from a distance is a close friend
- the process by which we interpret the world
- identifying who a sound was made from
What is transduction?
- process of converting stimuli into electrotechnical messages
- sense receptors
- we use this to go from physical sensation to perception
- psychical stimuli to converts to messages brain can understand
- Interpreted by action potentials, electromechanical, and neurotransmitters
What do Sense Receptors do?
- The process of transduction occurs via our sense receptors
- we have receptors of sight, hearing, taste, touch, and smell
describe how we process our external stimulus?
The processing of our external stimulus occurs through both bottom up and top down
what is Bottom up processing?
occurs when you experience a new stimuli, you are taking sensory input and trying to build a perception of them
What is Top down processing ?
is when our experiences in the past influences how we come to perceive our senses
The steps in sensation
- detect an external stimuli in the environment
- through transduction the physical soundwaves converted into electrochemical language of the brain
- processing information by comparing with previously stored information (top down processing) and or
through bottom up processing, the pitch, loudness, etc - The matching process then may result in a recognition interpretation of the externa stimulus
What is Absolute threshold ?
- Smallest stimulation required to detect a stimulus 50% of the time
- 50 because our ability to detect stimuli changes throughout the day
What is Just noticeable difference?
- there is a stimulus, and you can detect when the strength had changed
- there is a dimmer and you notice when it gets brighter or darker
- The smallest change needed in order to detect 50% of the time
What is Weber’s law?
- The ability to detect depends on the original strength of the original stimulus
- lifting a 50 pounds, then you lift 51. you won’t notice a difference
- lifting 1 pound, the lifting 2. You will notice the difference
What is Sensory adaptation?
- reduction in the sensitivity to stimulus with constant exposure
- Our bodies adapt and get used to it
- walking into smelly room
- going nose blind
- other people can notice
what is Multimodal perception?
- one sense has the potential to influence perception of another sense
- taste and smell work hand in hand
- won’t eat something if doesn’t smell good
What is Superaddictive effect?
- respond more strongly to multiple stimuli
- This can explain
how you’re still able to understand what friends are saying to you at a loud concert, as long as you are able to get visual cues from watching them speak. - In sum, we are able to process multimodal sensory stimuli, and the results of those
processes are qualitatively different from those of unimodal stimuli
What is the Sensation of Vision?
vison is light bouncing off of objects
What is Wavelength
(distance)
- color
- butterflies detect ultraviolet
- snakes detect infrared
- Humans only see within the 400- 700 range
What is Amplitude?
- (peak)
- brightness
- tall peak= brighter
- distance is how we perceive different colors
What are Photoreceptors?
- sensory neurons of vison-located in the retina
- densely packed in the fovea
- absent in the optic nerve
Describe the Process of vision
- light first enters the outer later called cornea and in through the pupil
- also controls the amount of light
- small pupil when there is a lot of right
- widening eye when little light
What does the lens do?
- focus light on retina on the through accommodation
- near objects, short and squishy
- far objects, long and skinny
Transduction in vison are….?
chemicals that react to light
What do Rods do?
- more sensitive
- peripheral
- low light
- works better at night
What are Cones used for?
- centre
- colour and detail
Who was the Trichromatic theory by
(Young, 1802; Helmhotiz, 1867)
What does the Trichromatic theory state?
- blue green and red
- All colours are perceived by additive mixtures
What are Opponent process theory?
- some colours can’t be created
- Red-green, blue-yellow, and black and white cells
- our perception of colour are different based on how much of each colour
- contrast rather than combination of hues
What is Gestalt laws of organization ?
- perceive stimuli near each other as grouped together (one on the right)
- seeing people play pickle ball, and you group them on a team
What does the law Similarity state?
perceive similar stimuli in groups
What does the law of continuity state?
We perceive stimuli as single uninterrupted thoughts
What does the law of Closure state?
- Perceive stimuli as a whole entity
- brains fill it in
What is Depth perception- monocular depth cues
Linear perspective
- parallel lines converge in the distance
- looks like an A even though it’s straight
What is Interposition?
- closer objects are in front
- boy with a cup in front
What is Relative height?
further objects are higher in the horizontal plane
What is texture in psychology?
objects further away have less detail
What is Relative size ?
objects further away are smaller
What are binocular depth cues ?
- binocular disparity
- Convergence
What is Convergence
This describes the reflex for our eyes to turn
inwards when viewing objects that are closer to us compared to objects that are further away, as you can see in the diagram in the middle.
What is binocular disparity ?
our right and left side see different inputs
What is Motion parallax
viewing objects that are closer as moving faster than objects that are further away. You experience
motion parallax when your driving on the highway and you see the signs that are closer as approaching much more quickly than signs that are further away.
What are the Difficulties with Vision?
- Prosopagnosia
- Acyanopsia
What is Acyanopsia
- inability to perceive movement
- teleportation
What is Prosopagnosia
- inability to process faces
- rely on other cues
- everyone will look like chickens
What are Soundwaves ?
- Mechanical vibrations
- through a medium which is usually air
What is Loudness
peak
- amplitude
What is Pitch ?
Wave frequency
What is Timbre?
- complexity of sound
- different instruments, same note, same loudness but it sounds different
What is the human Ear
Outer layer
- Visible part of your ear- Pinna (fleshy part) and ear canal (long canal)
What is the Tympanic membrane ?
called ear drums as they are responsible for vibration of sound in the middle ear
Describe the middle ear
- three middle ear bones : incus (anvil), malleus(hammer), and stapes (stirrup)
- smallest bones in the body-transmit vibration to cochlea
Describe the Inner ear
- Contains the cochlea- spiral shaped structure with fluid and contains the organ of corti- contains outer and inner hair cells
- Inner hair cells form synapse with auditory nerve - process of sensation to perception
What is physical stimulus ?
odours
What is Olfaction?
- 400 olfactory receptors
- lock and key
What is Gustation
- 5 basic taste receptors
- everything we taste is combination of the 5
- sweet, sour, bitter, salty, and umami
Well developed at birth
- sweet, sour, bitter, salty, and umami
What are the receptors in the sense of touch
- Mechanoreceptors
- Thermoreceptors
- chemoreceptors
- Nociceptors
- proprioceptors
What do Mechanoreceptors do?
stroking, stretching, or vibration of the
skin
What are Thermoreceptors for
responds to cold or hot temperatures
What do chemoreceptors responsible for?
responding to certain types of chemicals either applied
externally or released within the skin (such as histamine from an inflammation)
What are Nociceptors responsible for?
responsible for pain
What are proprioceptors for?
are responsible for our perception
of movement and body position.
