Sensation Flashcards
what is sensation?
transform energy of the universe into something we can understand, sensory input and transmission
why is quality of sensation very hard to quantify?
Because subjective experiences are hard to place in categories.
define transduction
receptor translates the physical energy
what is adaptation?
where an intense stimulus will not be sensed after a certain amount of time
define perception
integration of sensory features, to form the percept, but must also integrate memory
what are some characteristics of perception?
involves conciousness
processing occurs at a higher level of the brain
what is the first feature that must occurr for perception?
we must differentiate what kind of stimulous it is
what is the absolute threshold?
the detection of minimum energy required to stimulate the receptor; scientists define it as when you can detect the stimulus 50% of the time
what is the difference threshold?
detection of minimum change in energy
what does jnd stand for?
just noticeable difference
What principle must be in a pattern in order for a change to be detected?
It must be in a constant proportion
what is Signal Detection Theory?
the measurement of a threshold (whether the absolute or the difference) requires the observer to consciously perceive a stimulus
what is used to detect whether or not the subject is actually sensing anything
a false trial where there is no stimulus
define decision making theory
weighing up the outcomes of a decision
what are limitations of neuron’s all-or-none law
amplitude modulation not possible
what is mullers specificity?
The auditory nerve codes an auditory signal; the optic nerve, visual signals.
what is the quality of sound?
the emotion of experience
what is the frequency meausrement of sound?
Hz
what is the intensity unit of sound
Db
what is important to remember about the dB scale
It does not increase in a linear way, it is a log scale
what is the flap of the ear called?
pinnae
what four parts make up the middle ear?
ear drum, hammer, anvil, stirrup
what is the curled thing in the ear called?
cochlea
what happens for the cochlea?
when stimulous is received to the ear, the fluid in the cochlea is set in motion
what does the fluid in motion in the cochlea do?
the way the fluid moves activates little hairs in a certain way, and those little hairs are attached to nerves. those nerves can then be used to translate the sound
define frequency theory
frequency of times auditory nerve fires code frequency (coded by the same number of action potentials)
what are the problems frequency theory?
the nerve can only fire 1000 times a second, 1000Hz, but we can hear to 20000
what is place theory?
frequency coded by place stimulated on tympanic membrane. the intensity is then coded by the frequency of firing. thus, specific auditory nerve fibers are responsible for certain frequencies.
support of place theory?
neuronal population throughout the auditroy relay system (brainstem, thalamous, auditory cortex) do respond to very specific frequnecies.
problem with place theory?
low frequencies move the whole basilar membrane. we should therefore hear mixed frequencies, but we do not.
what type of frequencies in hearing loss are very rare?
Low frequencies
how do we localize sound?
time difference between arrival of sound to ears, and intensity difference between ears.
