The relationship between physical stimulus and its perceivedproperties is complex, very complex.
yeh, yeh it is.
What is sensation?
the process by which the sense organs gather information about the environment and sends this information to the brain for initial processing
What is perception?
the process of organisation and interpretation of sensory information.
Perception is immediate, fast, automatic,effortless and largely independent of other cognitive functions.
yep yep, uhuh uhuh.
What is absolute threshold?
the smallest amount ofenergy that a person can detect reliably (ie 50% of the time).
What is JND?
"just notice a difference": is the smallest detectable difference between a starting and secondary level of a particular sensory stimulus.
What is Weber's Law?
The size of JND between two stimuli (a standard and a comparison) is aconstant fraction of the level of physical stimulation provided by the standard.
What is sensory adaption?
The sensitivity of our sensory systems is dynamic: it changes as a result of prolonged stimulation.
What is The Importance of Relative Information?
The perceptual systems are geared towards the extraction of relative, notabsolute information.
Sensory Systems are Tuned to EcologicallyRelevant Information in the Environment
What do perceptual illusions reveal?
not errors but revealimportant principles of perceptual processing and the constraints that mediate perception. They are systematic and provide hints about the perceptual strategies of the mind.
Can perceptual illusions be eliminated?
NO. Perceptual Illusions can’t be eliminated by knowing “that they are illusory”:they are “cognitively impenetrable”.
What are the function of gatekeepers?
- detect harmful substances that should be rejected
- detect useful substances that should be consumed
What are odorants?
Odorants are compounds which are small enough to be volatile so it can be vapourised, reach the nose and dissolve in the mucus.
What is the process of olfaction?
1. Physical stimulus- odorants
2. Receptors- The roof of each nasal is called the nasal mucosa which contains olfactory sensory neurons
3. Transduction- From the olfactory bulb, neural signals are sent to the primary and secondary olfactory located at the temporal and frontal lobes respectively. Also the lymbic system - emotional response to smells
4. Sensory coding- shape pattern code for odor, odorants are coded by combinations of olfactory receptors called recognition profiles
What are the 5 basic sensations?
1. Sweet - sucrose
2. Salt- sodiums and chlorides
3. Sour - acids
4. Bitter - posions
5. Umami - amino acids
What is the process of gustation?
1. Physical stimulus
2. Receptors- Taste buds which are located in the papillae.
3. Transduction- The neuron signals travel across the tongue along cranial nerves, initially synapsing at the spinal cord then the thalamus. They eventually terminate at the frontal lobe of the brain.
4. Sensory coding & Perception- 5 tastes
What is sound?
Travels in waves
^ amplitude, ^ volume
^ frequency, ^ pitch
timbre is texture of sound,
complexity is multiple frequencies
What is the basic structure of the auditory system?
- Inner ear is filled with fluid much denser than air
- tiny bone structures in the ear amplify vibration for better transmission through the fluid
What is the process for hearing?
1. Physical stimulus - sound waves
3. Transduction- The outer ear collects & magnifies sounds in the air, middle ear converts wavesof air pressure into movements of tiny bones & the inner ear transforms thesemovements into waves in fluid that generate neural signals
What are the types of hearing loss?
1. Strucutural damage to the ear and its parts
2. Conductive- sound not conducted efficeiently enough leads to reduction in sound level. Can be surgically corrected
3. Sensorineural- damage to the nerve pathways leads to reduction in sound level AND speech understanding. CANT be surgically corrected
4. Central- damage likes in the CNS
What are cochlear implants?
- Tiny flexible coils with miniature electrode contacts
- Surgeons thread implants through round window toward cochlea apex
- Tiny microphone transmits radio signals to a receiver in the scalp
- Signals activate miniature electrodes at appropriate positions along the cochlear implant
What is proprioception?
is the sense of the relative position of neighbouring parts of the body.
- Kinesthesia: the sense of position of our body parts with respect to each other that allows us to perform movement
- Vestibular sense: provides information about the position of body in space by sensing gravity, movement and acceleration - factors critical for maintaining our sense of balance
What is the process of touch?
1. Physical stimulus-
2. Receptor- Mehanoreceptors- embedded in the dermis and epidermis layers of the skin: recognise type of stimulation and rate