Perception Flashcards
types of perception
Vision, audition, bodily senses, smell, taste.
makes everything else in psychology possible
Sensation
the ability to detect a stimulus - raw input/transduction of physical energy
transduction
translation process where different types of cells react to stimuli, creating a signal processed by CNS resulting in sensation
what is perception
processing input for meaning/action/understanding/making decisions
occurs in the brain
path of perception
stimulus > sense (transducer) > nerves/neurons > thalamus > cortex
Cortex
where sensation becomes perception
vestibular refers to
balances, bearing
proprioceptive refers to
action, movement
nociceptive refers to
pain
thermoreceptive refers to
temperature
Each sense will have its own…
Receivers: specialised receptors that receive/transduce
Transporters: nerves/neurons that transmit
Processors: areas of brain that process and make sense of it
Visual perception
Raw input > waves of light/electromagnetic radiation
Perception > image/picture of surroundings
Auditory perception
Raw input > waves of pressure in air
Perception > an idea of sound emitting object in surrounds
Tactile perception
Raw input > objects making contact with skin/ direct pressure
Perception > texture/type of object, relevancy/intensity
Gustatory perception
Raw input > substance/matter/organic/inorganic material dissolved in saliva
Perception > foodstuff or other, the taste
Olfactory perception
Raw input > airborne molecules, dissolved in mucus
Perception > detect of odour-emitting object, the smell
Vestibular perception
raw input > hair cells moved by liquid in cochlea
Perception > velocity of movement, orientation in enviro, effect of gravity
Proprioceptive “sense”
Raw input > motor action, muscle and joint movement
Perception > knowledge of limbs/body location in external space
Nociceptive sense
Raw input > (must reach certain threshold) extreme pressure/heat/cold and damage
Perception > knowledge of aversive stimulus, motivation to evade/withdraw
Thermoreceptive sense
Raw input > direct/ambient exposure to thermal energy
Perception > effect of temp (direct contact objects etc.)
Top-down processing
executive driven - prior knowledge etc. inform perception
can differ between individuals
happens through association
Bottom-up processing
stimulus driven - building features of raw input to a sensory outcome
reliant on sensory process, will be the same for most
temporary resolution
how well stimuli or events can be individuated/discriminated/detected/comprehended over time and precision at which this happens
spatial resolution
how well stimuli or events can be individuated/discriminated/detected/comprehended over space and the precision at which it happens
limit of temporal resolution
watching a movie and seeing smooth movement > it is actually still images
qualia
a quality or property as perceived or experienced by a person.
illusions
what we perceive is not always what is happening - if our perception is fallible
vision is dependent on…
light being received by the photoreceptors in our eyes
Colour blindness
absence/dysfunction of cone
can occur at retina or early in visual systems
Protanopia
absence of L-cones (red green)
Deuteranopia
absence of M-cones (green red)
Tritanopia
absence of S-cones (blue yellow)
cone monochromacy
one cone type
rod monochromacy
no cones at all
Cones are…
Photopic, work well in the light
centrally-dense, peripherally sparse
Rods are…
Scotopic (concerns light intensity), work better in dark
Centrally sparse, peripherally dense
The blind spot
where all nerve fibres meet up and exit the eye (optic nerve) - there are no photoreceptors in this location so it is blind
Why dont we see upside down?
The brain caters for this but apparently we do in our first moments of life
Visual pathway
lateral geniculate nucleus (LGN) on each hemisphere receives input from visual field on the opposite side (V1)
Dorsal pathway - action
Ventral pathway - identification
cortical magnification
magnification of the central/foveal input, focusing
V1 - primary visual cortex
after visual field is received and ordered by layers of LGN it is projected to V1
FFA
Fusiform Face Area (inside cortex)
Have you seen a face or have you not?
what is audition used for?
communication
navigating immediate environment (locating sound-emitting objects, proximity, relevance)
music + socialisation
sound
when something vibrates or displaces air in some way, pressure waves are created
two main characteristics of sound
frequency: how many wave cycles occur in a period of one second (indicative of pitch) Hz
amplitude: height of the wave (intensity/power) dB
A1 - primary auditory
frequencies received at the base of the cochlea are processed at the base of A1, and frequencies received at the apex of the cochlea are processed at the apex A1
Where is speech stimuli recieved after processing?
Wernicke’s area, then if a response is required connection occurs with Broca’s area and then motor cortex to initiate speech
Interaural Time Difference (ITD)
using extremely precise temporal capabilities of auditory system to give indication of the external location of a sound emitting object in the horizontal dimension
Can sound fall onto each ear at different times?
yes
Interaural level difference (ILD) or interaural intensity difference (IID)
sounds of certain frequencies can vary up to 20dB from ear to ear
How do we find elevation?
The pinna and shape of our head will reveal differences in pitch of sound-emitting objects in the same horizontal dimension but in differing vertical elevation.
Temporal discrimination
the ability of the auditory system to discriminate the raw input into perception
McGurk Effect
hearing something different because what you are seeing has changed
perception of gravity
utricle and saccule contain tiny crystals of calcium carbonate that aid in the perception of gravity
Benign paroxysmal positional vertigo (BPPV)
dizziness in certain head positions - fixed by Brandt-Daroff Exercise to get crystals out of semicircular canals
Vestibulo-ocular reflex
Vestibular system communicates to muscles in eyes to maintain fixation when the head is in motion
Somatosensation
how do things feel - tactile sense allows for a lot of manual motor tasks
passive touch
an object can touch our skin in one location - touching YOU
active touch
YOU touching SOMETHING
haptic perception
collection of information from many sensory subsystems
4 mechanoreceptors in touch
Meissner - fast adapting, small RFs, detect 5-50Hz
Merkel - slow adapting, small RFs, texture/form/pattern
Ruffini - slow adapting, large RFs, skin stretch, readjust grip
Pacinian - fast adapting, large RFs, detect 50-700Hz
manual tactile perception
stimulus received at skin > travels up spin > thalamus >somatosensory cortex >processed + mapped
tactile localisation
localise touch in space not just on the skin
somatopic reference
skin based
external reference
space based - vision, proprioception, and representations of the external world aid in localising the tactile event in space
A-delta fibres
signal acute pain, highly myelinated (fast)
C fibres
signal delayed and more diffuse pain (slower)
What is referred pain?
where visceral pain (from organs) is experienced by the skin.
Bi-stable perception
where the same image can be seen in different ways or hidden objects and images
optical illusion
a discrepancy between what is visually perceived and the objective reality of that sensory information
why are optical illusions important
infer how visual systems work
Sweet
What: sugars, simple carbs (e.g. glucose, fructose, saccharin, etc.)
Why: energy rich, calorific
Salty
What: ions from some salts (e.g. sodium)
Why: electrolyte balance
Sour
What: some acids, H ions (e.g. vinegars, fermented products)
Why: detecting acidity (which can be dangerous at high levels), spoiled food
Bitter
What: lots of varied compounds
Why: most poisons have a bitter taste
Umami (savoury)
What: some amino acids, glutamate, MSG (wide variety of things, but e.g. cured meats, cheese, soy)
Why: detect protein consumption
Oleogustus (Fat)
What: fatty acid (e.g. in oils, butter, etc.)
Why: signal fat consumption (??)
More of a feeling rather than a taste
Lingual Papillae
the various types of buds on the tongue
Filiform Papillae
no taste function, keratinous tissue, elastic in part, dense
Vallate Papillae
occupied mostly on back of tongue, taste buds buried inside “moats”
Fungiform Papillae
occupied mostly on front of tongue, taste buds buried in each papilla
Foliate Papillae
occupied mostly on side of tongue, in fold-like form, taste buds buried in folds
Sensation of taste
matter broken down by teeth/tongue > dissolved in saliva > received by microvilli > transduced by receptor cells > received by nerve fibres > sent through processing
The Labelled-Line Model
each gustatory afferent nerve fibre carries information from one type of taste receptor cell, responding to a single taste category
taste categories remain distinct, the perception of compounds is preserved
Is spicy a taste?
No, it is a chemosensory irritation at mucosal membranes and areas with TRPV1 receptors
Preference for taste
density of fungiform papillae and presence of gene gives the ability to taste more intensely
sensitivity to each taste
- sweet
- salty
- sour
- bitter
sensation of smell
molecules (odorants) must be ‘volatile’, (a gaseous state) > reach mucosa and get dissolved > received by cilia > transduced by OSN > sent to glomerus > mitral cell > received by nerve fibres > sent for processing
How can lock and key be used to explain smell
cilia capture volatile molecules through a lock a key system - each receptor activates a different part of the olfactory bulb
If olfaction doesn’t go through the thalamus first, then where does it go?
- Frontal lobe where it can be identified
- Hypothalamus amygdala and the limbic system: emotional ground control, trigger memories
maybe for evolutionary reasons
perception of colour
The colour that something is is the wavelength getting reflected and it absorbs the other ones that aren’t seen
What can help with less severe colour-blindness
multi-notch filtering glasses
silencing
motion can appear to “silence” changes in contrast, colour, brightness etc. because brain is paying attention to global motion rather than the local changes
Ponzo illusion
linear perspective influences your perception of the length lines
penrose triangle and stairs
globally - appears sound
locally - realise that in tangible 3D reality, it is impossible
Blue-field entopic phenomenon
White sparkles - White blood cells moving in the capillaries in your eyes and refracting it onto your retina.
Floaters
Tissue, dirt, spec in the jelly (vitreous humour) of your eye
Moves with your eye so you can’t fixate on it
Retinal blood vessels
White light in the corner of your eye when they’re closed.
Blood vessels casting shadow on retina
why is attention important?
plays a large role in how much information is actually consciously perceived, encoded, processed, and/or remembered.
attentional load
how much you can keep in focus at one time
odour evoked autobiographical memory
Smell made you remember something from your past
Memories linked to smell often tend to be stronger and relate to childhood memories. More perceptual rather than conceptual
flavour
a result of the integration of both gustatory and olfactory sensory input
process of flavour
primary olfactory inpur proceeding gustatory input > gustatory input > secondary olfactory input
flavour can also be influenced by
vision, audition, tactile, thermo/nociceptive, trigeminal
Palatability
pleasure associated with foods and fluids that are agreeable to the palate
can be influenced by homeostatic needs (energy, nutrition, thirst)
Mouth feel
feel of food/fluid in your mouth
using somatosensory subsystems
can be associated with hedonic reward
Gestalt
the whole is other than the sum of its parts - organisation is independent of raw sensory makeup/features
syncopation
When rhythms are off-beat, only some fall off it.
Musical structure produces this incredible desire to dance
Fall-off the beat: opening up spaces in the rhythmic surface, inviting the body to fill them in through synchronised body movements, engaging the body in music.
Sensorimotor Coupling
coupling sensory and motor processes whilst in some form of action
Grove
the urge to move in response to music, combined with the positive affect associated with sensorimotor coupling, in a seemingly effortless way
modulation in music
pieces of music using more than one group of pitches
psychophysics
The study of the relationship between the physical stimulus and the psychological reaction
What is the main physical determinant of pitch?
frequency of a wave
size constancy
perceived object size does not vary in spite of the variations in size of the retinal image
Weber’s Law
you measure how different Test stimuli have to be relative to a Standard stimulus before observers can reliably detect the difference, the magnitude of the Just noticeable difference (or Discrimination Threshold) will always be proportional to the magnitude of the Standard Stimulus
Cornea
transparent part of the eye that covers the iris and the pupil and allows light to enter the inside
lens
biconvex, relatively acellular, optically transparent intraocular structure
iris
controlling diameter and size of the pupil
retina
light-sensitive layers of nerve tissue at the back of the eye that receive images and sends them as electric signals through the optic nerve to the brain.
sclera
white outer layer of eye
pupil
round opening in the eye
ciliary body
middle layer of the eye and helps change shape of lens
