Perception Flashcards
What can sound be defined as?
It can be defined as waves of changing pressure travelling through air
What is a pure tone?
It has an amplitude and a frequency
In a pure tone, what is equivalent to frequency?
Perceived pitch
What are natural sounds?
Consist of pure tones of many frequencies added together e.g., voice
What is an amplitude?
the maximum air pressure in each cycle
What is frequency?
the number of cycles of changing air pressure per second
What do we measure frequency in?
We measure it as hertz
What are the two physical properties of sound?
frequency and amplitude
What happens when amplitude is increased 10 times?
Loudness increases approximately 4 times
Where does sound come along?
Sound comes along the auditory canal to the ear drum
What does sound influence?
Sound influences the eardrum
What is the eardrum connected to?
It is connected to three small bones:
malleus, incus &stapes
What does the cochlea have connections to?
Connected to the auditory nerve
If you were to unroll the cochlea, what would you see?
the basilar membrane
What does the basilar membrane have?
The basilar membrane has a lot of mini hairs on it
What does each part of the basilar membrane vibrate to?
It vibrates to a particular frequency
What does the basilar membrane do?
It bends and contorts dependent upon the frequency of the sound
What does the basilar membrane hairs do?
They fire depending upon the frequency and amplitude
What is the basilar membrane at the base also known as?
It is also known as oval window
What does the basilar membrane at the base respond to?
It responds to high frequency sounds
What does the basilar membrane at the tip respond to?
It responds to low frequency sounds
What is the basilar membrane at the tip also known as?
It is also known as the apex
What does the basilar membrane in the middle respond to?
It responds to medium frequency sounds
What are hair cells?
They are mechanoreceptors; they are sensory instruments that allow us to perceive the physical properties of sound as perceptual ones
What do hair cells send?
They send electrical signals to the brain through the auditory nerve
What does each hair cell signal?
Each hair signals the amplitude of one narrow range of frequencies in the sound
What is the perception of loudness based on?
The perception of loudness is based on the firing rate of the hair cells
What are the 3 physical dimensions of sound?
- frequency
- amplitude
- complexity
What does frequency correspond to?
Corresponds to our perception of pitch
What does amplitude correspond to?
Corresponds to our perception of loudness
What does complexity correspond to?
Corresponds to our perception of timbre
What is fundamental frequency?
It is the lowest-frequency component of the sound
What is a masking sound?
It is a sound with the intention to cover up the human detection of the other sounds
What is the absolute threshold?
It is the point in which on 50% of trials you do not detect things below it
What are examples of a masking sound?
coughing to mask sound of a fart or turning the tap on to hide the sound of you peeing
Signals from gustatory receptors in the mouth are integrated with signals from 4 other receptor types, what are they?
1- olfactory receptors
- light receptors
- touch receptors
- sound receptors
What is visual acuity?
It is the ability to see fine detail
What is visible light?
Portion of electromagnetic spectrum seen
What is the retina composed of?
It is composed of photoreceptor cells, the rods, and cones, beneath a layer of transparent neurons, the bipolar and retinal ganglion cells
What is the fovea?
It is the small dip in the retina
What is the fovea responsible for?
It is the area responsible for high acuity vision
What is the fovea made of?
It is made entirely of cones
What happens at the optic chiasm?
Information at the right visual field travels along the pathway on the left hemisphere whereas information on the left visual field travels along the pathway on the right hemisphere
Where do visual signals relay to?
They relay to primary visual cortex via the lateral geniculate nucleus
How do the axons on the retinal ganglion cell leave the eye?
Via the optic nerve
Where do the long nerve axons travel to?
The long nerve axons travel all the way to the midbrain structure called the thalamus and relay within the LGN (lateral geniculate nucleus). This is the first synapse
After travelling to the first synapse, where do long axons travel to?
The long axons fan out travelling subcortically under the temporal and parietal lobes of the brain to the occipital cortex, where they terminate in the occipital lobe. They key recombination of information takes place at this point.
What are the two visual systems?
- ventral stream
2. dorsal stream
Where is the ventral stream?
Heading to the inferior temporal lobe
What is the ventral stream used for?
This is used to identify things, people, objects
Where is the dorsal stream?
Coming from primary visual cortext heading to the superior parietal lobe
What happens at the dorsal stream?
This is where the visual info is used to control movement
What is visual perception about?
Visual perception is about transforming the patterns of light that enter our eyes into some kind of representation of the world that helps us recognize and interact with the objects and people around us
What does the fusiform face area respond to?
It responds to faces more than other subjects
What does the parahippocampal face area respond to
?
It responds preferentially to places, such as pictures of houses
What is the extrastriate body area specifically involved in?
Specifically involved in the perception of body parts
What is change blindness?
It is when an observer fails to notice a large change to objects or scenes and this typically occurs after there has been some visual disruption
What does change blindness demonstrations show us?
It show us that our internal representation of the outside world is not as rich as our experience of seeing would indicate
What is external attention?
attending to stimuli in the world
What is internal attention?
attending to one line of thought over another or selecting one response over another
What is overt attention?
directing as sense organ toward a stimulus like pointing your eyes or turning your head
What is covert attention?
attending without giving an outward sign you are doing so
What is divert attention?
splitting attention between two different stimuli
What is sustained attention?
continuously monitoring some stimulus
What is visual attention?
the selection of some visual stimulus or set of visual stimulus at the expense of others for further visual and cognitive analysis and often for the control of behaviour
What is space based theory?
- Attention is like a spotlight which moves about and allows us to selectively attend to parts of the visual world
What is the efficiency of visual search measured in?
Measured in terms of search slope or ms/item
What is the efficiency of visual search?
It is the average increase in RT for each item to the display
What is the binding problem?
- The challenge of trying different attributes of visual stimuli, which are handled by different brain circuits, to the appropriate object so we perceive a unified object e.g., a vertical red bar moving to the right
What is illusory conjunction?
An erroneous combination of 2 features in a visual scene e.g., seeing a red X when the display contains red letters and Xs but no red Xs
What do illusory conjunctions provide evidence of?
provide evidence that some features are represented independently and must be correctly bound together with attention
What is scene-based guidance?
It is information in our understanding of scenes that helps us find specific objects in scenes e.g., a mug or bowl will typically be found on a horizontal surface and a picture will typically be found on a vertical surface
What does cognitive ethology advocate?
It advocates the studying of behaviour under realistic conditions
