Week 7 Flashcards
Sensation
The physical process during which our sensory organs-those involved with hearing and taste, for example-respond to external stimuli. our sense organs are engaging in transduction, the conversion of one form of energy into another
Perception
After out brain receives the electrical signals, we make sense of all this stimulation and begin to appreciate the complex world around us
Absolute threshold
The smallest amount of stimulation needed for detection by a sense
signal detection
method for studying the ability to correctly identify sensory stimuli
How do we measure absolute thresholds
using a method called signal detection. Involves presenting stimuli of varying intensities to a research participant in order to determine the level at which someone can reliably detect stimulation in a given sense
differential threshold/ just noticeable difference
The smallest difference needed in order to differentiate two stimuli
Weber’s law
States that just noticeable different is proportional to the magnitude of the initial stimulus
How does experience influence hoe our brain processes things
stimuli we’ve experienced in our past will influence how we process new ones.
Top-down processing
Experience influencing the perception of stimuli
Why don’t we feel the weight of our clothing
When we experience a sensory stimulus that doesn’t change, we stop paying attention to it.
Bottom up processing
Building up to perceptual experience from individual pieces
Sensory adaptation
Decrease in sensitivity of a receptor to a stimulus after constant stimulation
How vision works
▪ When we see an object, we are actually seeing light bounce off that object and into our eye
▪ Light enters the eye through the pupil, a tiny opening behind the cornea
▪ The pupil regulates the amount of light entering the eye by contracting in bright light and dilating in dimmer light
▪ Once past the pupil, light passes through the lens, which focuses an image on a thin layer of cells in the back of the eye, called the retina
▪ Because we have two eyes in different locations, the image focused on each retina is from a slightly different angle (binocular disparity), providing us with our perception of 3D space (binocular vision)
Light is transduced, or converted into electrical signals in the retina by specialized cells called photoreceptors
▪ Electrical signal is sent through a layer of cells in the retina, eventually travelling down the optic nerve
* After passing through the thalamus, this signal makes it to the primary visual cortex, where information about light orientation and movement begin to come together
* Information is sent to a variety of different areas of the cortex for more complex processing
two types of photoreceptors in the retina
rods and cones
Rods
primarily responsible for our ability to see in dim light conditions, such as during the night
Cones
provide us with the ability to see colour and fine detail when the light is brighter
how are rods and cones different
differ in their distribution across the retina, with the highest concentration of cones found in the fovea (central region of focus), and rods dominating the periphery
Retina
Cell layer in the back of the eye containing photoreceptors
Binocular disparity
Difference is images processed by left and right eyes
Binocular vision
Our ability to perceive 3D and depth because of the difference between the images on each of our retinas
Primary visual cortex
Area of the cortex involved in processing visual stimuli
Ventral pathway
Pathway of visual processing. The “What pathway
dorsal pathway
Pathway of visual processing. The “where” pathway
Night vision
takes around 10 minutes to turn on, a process called dark adaption. Because our rods become bleached in normal light conditions and require time to recover
dark adaptation
Adjustment of eye to low levels of light
light adaptation
Adjustment of eye to high levels of light. Happens almost instantly compared to dark adaption
colour vision
Cones allow us to see details in normal light conditions, as well as colour. Cones respond preferentially, not exclusively, for red, green and blue
Trichromatic theory
theory proposing colour vision as influenced by three different cones responding preferentially to red, green and blue. Does not explain the odd effect that occurs when we look at a white wall after staring at a picture for 30 seconds
Opponent process theory
theory proposing colour vision as influenced by cells responsive to pairs of colours
Sound waves
changes in air pressure. The physical stimulus for audition
amplitude/ intensity of a sound wave
cods for the loudness of a stimulus; higher amplitude sound waves result in louder sounds
pitch of a stimulus
coded in the frequency of a sound wave
timbre
quality of a sound
How we sense sound waves from our environment
Sound waves are funneled by your pinna into your auditory canal. Sound waves eventually reach a thin, stretched membrane called the tympanic membrane, which vibrates against the three smallest bones in the body- the malleus, the incus, and the stapes- collectively called the ossicles.
Both the tympanic membrane and the ossicles amplify the sound waves before they enter the fluid-filled cochlea, a snail-shell like bone structure containing auditory hair cells arranged on the basilar membrane
After being processed by auditory hair cells, electrical nerves are sent through the cochlear nerve to the thalamus, and then the primary auditory cortex of the temporal lobe
vestibular system
Parts of the inner ear involved in balance. comprised of three semicircular canals-fluid filled bone structures containing cells that respond to changes in the head’s orientation in space
How are we able to maintain our gaze on an object while we are in motion?
Information from the vestibular system is sent through the vestibular nerve to muscles involved in the movement of our eyes, neck, and other parts of our body
Somatosensation
Ability to sense touch, pain, and temperature