Exam 1 Flashcards
What is the difference between sensation and perception?
Sensation: ability to detect a physical stimulus; i.e. touch on shoulder
Perception: act of giving meaning to detected stimulus; i.e. romantic touch or TSA touch
What is psychophysics and who came up with it?
Psychophysics: science of defining quantitative relationship between physical stimuli and psychological experience of these stimuli
Created by Gustav Fechner
What is another concept other than psychophysics that Gustav Fechner came up with?
Panpsychism: everything has a mind
What is psychometric function and how do we measure it?
Psychometric funtion: relationship between physical stimulus (x) and sensation intensity (y)
Measured using magnitude estimation
* participants assign estimated value to a physical stimulus
Why are most psychometric funtions not linear?
Observers are not perfect
What does Weber’s Law state?
The just noticeable difference (JND) is a constant fraction of the comparison stimulus
What does Fechner’s Law state?
The magnitude of perceived sensation increases proportionally to the logarithmic of stimulus intensity
Observer is less sensitive to high physical intensities than low physical intensities
What is the just noticeable difference/difference threshold?
Smallest difference detectable between two stimuli
What is the absolute threshold?
Minimum amount of physical sitmulus intensity necessary for person to detect 50% of the time
What are the different methods of testing used to find the absolute threshold?
- Method of constant stimuli
- Method of limits
- Method of adjustments
What is the procedure for method of constant stimuli?
- Present tones of different volumes in random order
- Participants report whether they could hear it or not
- Each volume level tested multiple times
Most accurate but time-consuming
What is the procedure for the method of limits?
- Present tones in ascending/descending order
- Participants report when they can hear it
- Multiple runs of ascending and descending tones
- Average = threshold
What is the procedure for method of adjustment?
Participants adjust volume until they can hear tone –> average = threshold
Who came up with the idea for signal detection theory and what does the theory state?
Created by Green and Swets
Observer’s goal is to detect signal amonst noise
What is the response criterion and how does it shift?
Response criterion: cutoff point for when you say “signal” vs. “noise”
Shifts depending on desired type of error
What is the difference between having a “liberal” response criterion vs. a “conservative” response criterion?
“Liberal” - will get every instance of phone ringing but lots of false alarms (right dom.)
“Conservative” - never mistake noise for phone ringning but lots of misses (left dom.)
How does the graph of someone with no sensitivity compare to someone with high sensitivity?
signal detection theory
No sensitivity - phone and noise lines almost overlap
High sensitivity - phone and noise lines are barely intersecting
What is the base rate of neurons?
Base rate: random firing of neurons with no stimulus present
What are the dendrites responsible for?
Receive information from other neurons
Where are action potentials generated?
Axon hillock
What is the axon responsible for?
Conduct action potentials away from the cell body
How was the action potential discovered and by who?
Isolate giant neuron from squid –> saw voltage increases because Na+ rushes into axon and pushes K+ out of the axon
Discovered by Hodgkin and Huxley
What are the stages of the action potential?
- Depolarization - voltage increases; cell “fires”
- Repolarization - voltage decreases
- Refractory period - cannot fire during this time
- Resting state
What happens at the synapse?
- Neurotransmitters released from presynaptic neuron
- Neurotransmitters bind to receptors on postsynaptic neuron
- Different neurotransmitters can either excite or inhibit the postsynaptic neuron
What are sensory receptors?
Transfers stimulus energy and turns it into electrical energy that neurons can use to communicate (transduction)
What is receptor specifity?
Most receptors are optimally tuned for a specific type/pattern of energy
What hogs the most energy in our body?
Blood vessels in the brain
What are glial cells?
Maintain integrity of the neurons and act as structural support for neurons
Which bypasses which: cranial nerves or peripheral nervous system?
Cranial nerves bypass peripheral nervous system
Do we have more glial cells or neurons in our brain and by how much?
3 x more glial cells than neurons
What is cranial nerve I? Sensory or motor nerve?
Olfactory - smell
Sensory
What is cranial nerve II? Sensory or motor?
Optic - vision
Sensory
Which cranial nerves are responsible for the muscles that move the eyes?
III (oculomotor), IV (trochlear), and VI (abducens)
Which cranial nerves are responsible for sensation and motor?
V (trigeminal), VII (facial), IX (glossopharyngeal), X (vagus)
Which cranial nerves are responsible for vestibular and auditory?
VIII (vestibulocochlear), XI (spinal accessory), XII (hypoglossal)
What is EEG? What are the pros and cons?
EEG: measures voltage fluctuations over time (brainwaves) from populations of neurons in the brain
Pros - relatively cheap and great temporal (time) resolutoin
Cons - poor spatial resolution because skull gets in the way of electricity and hard to tell what part of brain activity is coming from
What is an fMRI? What are the pros and cons?
fMRI: measures amount of oxygenated blood in a given brain region; blood-oxygen level-dependent (BOLD) signal
Pros - high spatial resolution
Cons - expensive and poor temporal resolution
What did the Brady et. al study from 2008 reveal?
memory study
Participants remembered 90% of images in recall test
What is refraction?
Direction of light waves can be altered when they pass through one medium to another
Where is light transduced into a signal in the eye?
Retina
What is the inner chamber of the eyeball called?
Vitreous chamber
What part of the eye is the first step in focusing light?
Cornea
Why is the anterior chamber of the eye filled with fluid?
Easier for the body to regulate the shape and pressure of the eye
What part of the eye controls the size of the pupil?
Iris
What does the lens of the eye do?
Focus light by bending itself
What are the two types of photoreceptors found within the retina?
Cones: specialized for color vision
Rods: specialized for night vision
What are the different types of light adaption?
- Pupil dilation
- Photopigment regeneration
- Neural circuitry
- Duplex retina
How is pupil dilation a form of light adaption?
Dilates in darkness to let more light in
How is photopigment regeneration a form of light adaption?
Photopigments used to transduce light into neural signals and if photopigments regenerate fast enough, we can perceive very bright stimuli