cog psych Flashcards
what is cognitive psychology?
scientific study of thought and experience
how is behaviourist information processing visualised?
stimulus
attention
perception
thought processes
decision
response of action
humans are ____ ______ machines?
stimulus response
how is information received through the senses processed?
by a series of modules that change the information in a systematic way
the output of these processing modules ultimately causes an observable response
in what order must this process occur?
sequentially (in chronological order)
name one assumption of the input output approach
serial processing
only one step at a time, no information travels backwards, just in and then out
name another assumption of the input output approach
bottom up processing
all processes are directly triggered by a stimulus, lower level sensory processes drive higher order thoughts and decisions
name a criticism of the input output approach
does not allow for parallel processing
name a criticism of the input output approach
ignores top down processing
what is top down processing?
processing where higher order cognitive processes and thoughts determine how information is processed at lower levels
e.g. when our prior knowledge and expectations about the world shape how we perceive the world
name another criticism for the input output approach
oversimplification
how does representation work in bottom up processing?
everything that we see and experience in the world comes from our brains
name an example of bottom up processing
person A sees person B walking a dog and registers it is a dog in their brain
in order for person A to register the dog as a dog they must first have an experience of seeing a dog
this means that these neurons in the brain fire in a pattern that produced or represents the dog
how could neurons represent complex information?
some neurons have preferred stimuli (i.e., respond to a certain orientation, colour, or even a complex concept like Luke Skywalker or Jennifer Aniston)
this means when these stimuli are presented, the neurons fire more than when other stimuli are presented
sometimes referred to as grandmother cells
when responding to particular concepts, does a singular neuron fire?
no
what is rate coding?
greater rate of a neuron’s response is used to code/represent information
the information is represented in how fast each neuron fires, whether it fires quickly or slowly, depends on the information it represents
what is temporal coding?
greater synchrony of the responses of several neurons is used to code information
when it fires and if multiples neurons fire at the same time are more important
what are the 3 ways we study cognition?
experimental cognitive psychology
cognitive neuropsychology
cognitive neuroscience
what is experimental cognitive psychology?
studying behaviour in controlled laboratory settings
shed light onto cognitive processes by using clever experimental manipulations
traditionally, experimental psychology doesn’t care about the underlying brain processes
instead of “brain measures”, cognitive psychology uses behavioural measures like reaction times (RT) or accuracy as indirect measures
what experiment is used as an example in experimental cognitive psychology?
the Stroop test
asked to name the visual colour of the word and ignore the actual word (which is a colour)
what does the stroop test, test for?
to test whether word reading is automatic. if it is, it will interfere with colour naming and cause longer reaction times and more errors
name a limitation of experimental cognitive psychology (1)
ecological validity
findings are unlikely to be generalised outside of the lab
stroop test is good to measure peoples self control but unlikely to be useful for other behaviours
name a limitation of experimental cognitive psychology (2)
face validity
only provides indirect measures of cognitive processes
measure through an indirect window of behaviour to gain insight into the cognitive processes
name a limitation of experimental cognitive psychology (3)
do psychological concepts even exist?
scientists should guard against tacitly granting reality to things simply because we have words for them
what is cognitive neuropsychology?
studying cognition in patients with brain injury e.g. brain trauma or a head injury
we assume if a patient has damage in one region of the brain and becomes unable to do certain things we can infer that region is more important for that action/thing
name a limitation of cognitive neuropsychology (1)
no baseline
we don’t exactly know what the patient could do before their injury
name a limitation of cognitive neuropsychology (2)
generalisation
lesions in some areas of the brain are relatively common, while others are very rare
name a limitation of cognitive neuropsychology (3)
modularity
cognitive process X is likely distributed across multiple areas, not just one
what is cognitive neuroscience?
relates brain structure and brain function to cognitive processes
typically done by recording brain activity while participants perform cognitive tasks
what are the tools to study the brain?
Electrophysiology (EEG)
Structural Imaging (MRI)
Functional Imaging (fMRI)
Brain stimulation (TMS)
name the lobes of the cerebrum from front to back
frontal
parietal
occipital
temporal
cerebellum
describe electrophysiology: single-cell recordings
very small electrode records neural activity from within axon (intracellular) or from outside axon membrane (extracellular)
usually only obtained from animals, when is this justified
sometimes we have the rare chance of recording from (human) patients with epilepsy
describe electroencephalography (EEG)
electrical activity of a large number of neurons all firing together, recorded via electrodes on the scalp
allows us to measure neural activity in essentially real-time (millisecond scale)
not measuring individual neurons but rather a large number of neurons firing together
describe event-related potentials (ERPs)
measure EEG response to the same stimulus/task over and over
average waveform to generate an “event-related potential” (ERP)
just like averaging reaction times to get a cleaner estimate of the “true” effect
we can compare the ERPs between different psychological conditions (e.g. attended vs unattended stimuli)
name two advantages of EEG/ERP
very good temporal resolution (milliseconds) i.e. when something happens
portable and relatively cheap
name two limitations of EEG/ERP
poor spatial resolution (centimetres) i.e. where in the brain it happens
infinite number of possible origins for any signal recorded at the scalp, so we need solid computational models to make an informed guess
describe magnetic resonance imaging (MRI)
very strong magnetic field
0.5 - 7 Tesla (T)
60,000 times the magnetic field of the earth
what are the basic principles of MRI?
single protons in water molecules (A) tend to align to the powerful and stable magnetic field generated by the scanned (B)
we then disturb this alignment with short radio-frequency pulses and measure the resulting change in magnetic field (C)
different parts of the brain take different times to relax from the radio frequency disturbance, and show as lighter/darker
describe a structural MRI
used to determine how much brain matter there is, what shape it is and where the different regions are
describe diffusion tensor imaging
DTI can image white matter fibres (bundles of axons) by measuring the direction of water diffusion
allows us to study how cognition/perception is supported by connections between brain regions
what does BOLD stand for?
Blood Oxygenation Level Dependent (signal)
describe functional MRI
measures indirectly how brain activity changes as a function of doing different kinds of things
measures the BOLD
describe what occurs during BOLD
active neurons need oxygen
the brain starts supplying oxygen to active areas, producing an “overshoot” in oxygenated blood
oxygenated blood cause less magnetic field disturbance than deoxygenated blood, so active brain regions will have higher signal
describe subtraction logic
ppts study a list of words and then are visually presented with words individually on the screen and asked if it was studied or not (i.e. old or new)
remembered vs baseline does not isolate the cognitive process we care about
cognitive tasks should be designed so that the only difference between two conditions is the thing you are interested in
name an advantage of MRI
very good spatial resolution (millimetres)
name a limitation of MRI (1)
poor temporal resolution
name a limitation of MRI (2)
not a measure of neurons themselves
requires an indirect interference that neurons are firing because that part of the brain is using more oxygen
why do we use brain stimulation techniques?
to know if a particular part of your brain is important for a cognitive process, we need to change the activity of that part of the brain and show that it changes behaviour
i.e. we need causal evidence, not just correlational
describe transcranial magnetic stimulation (TMS)
short magnetic pulses that briefly affect electrical activity in a localised patch of brain tissue under the coil
is typically applied either before or during a cognitive task
can have positive or negative effects on task performance
name an advantage of brain stimulation (1)
causal evidence that a particular brain region is important for a cognitive function
name an advantage of brain stimulation (2)
mostly non invasive
i.e. safe and painless for healthy populations
name a limitation of brain stimulation (1)
stimulation of the brain is very weak as it happens from outside of the head therefore, the effects are often weak
name a limitation of brain stimulation (2)
potential risk to individuals with history of epilepsy
name a limitation of cognitive neuroscience (1)
expensive/invasive
worth the expense?
often means that sample sizes are small
generalisable?
name a limitation of cognitive neuroscience (2)
theories
emphasis in the literature on measuring brain effects rather than testing theories
name a limitation of cognitive neuroscience (3)
does it help us understand cognition?
could a neuroscientist understand a microprocessor?
what do illusions suggest?
the brain doesn’t see at all
it receives electrical signals about how light interacts with the eye, and then it must infer what is out there in the world
your cognitive abilities have limits
you aren’t as aware of the world as you think you are
how do we know what we see in an image is actually there?
we make these inferences just from photons which are bouncing off the surface in front of us and coming into our eyes and hitting the retina
name the steps from eye to cortex
reception
transduction
coding
describe reception
absorption of physical energy - i.e. photons
physical energy enters our eyes and interacts with photoreceptors after hitting the retina
describe transduction
physical energy is converted into an electrochemical pattern in the neurons
our photoreceptors convert this energy from the photon into electrochemical signals which then get sent down to neurons, our brain cells in our brain
describe coding
one to one correspondence between aspects of the physical stimulus and aspects of the resultant nervous system activity
what is the difference between rods and cones?
rods are concerned with vision in dim light and movement
whereas cones are concerned with colour vision and sharpness of vision
what is the retina?
the back surface of the eye which is covered in tiny little photoreceptors (rods and cones)
where are cones primarily located?
right where we’re looking at in the fovea (small depression within the neurosensory retina where visual acuity is the highest)
where are rods primarily located?
primarily distributed in the periphery that is outside of or around what we are looking at
is colour processed as colour through the retina?
no, but can still be perceived
what light do humans respond to?
visible light, the part of the much wider electromagnetic spectrum that our cones and rods respond to
the human eye is not sensitive to light in the green range
what is the trichromatic theory?
that all colours of the spectrum can be produced by mixing 3 primary colours
Helmholtz proposed that there must be three types of colour receptors in the human eye, responding to different wavelengths of light
what are the three types of cones that prefer different wavelengths?
short (blue)
medium (yellow-green)
long (red)
what is the opponent-process theory?
the idea that maybe these inputs from our 3 different types of cones are processed in a kind of opposition manner to not give us how blue something is etc but actually tell us where something falls on a scale from red to green and from blue to yellow or on a scale from dark to light
this process works by taking the input from red and green cones and subtracting them
how do you calculate the signal which describes reddish greenness where something falls between red or green?
the difference between red and green cones input and sending that electrical signal to the brain
what is colour constancy?
the tendency for a surface to appear to have the same colour despite a change in the wavelength contained in the illuminant (the light source)
evolutionarily very helpful
does visible light (humans view) reflect what the object actually is?
no, a flower that appears to our visible light vision may look completely different to a butterfly with ultraviolet vision. None is more right than the other so its hard to state what is the true perception
what are the two pathways that occur after the retina?
Parvocellular (P) pathway
Magnocellular (M) pathway
what is the parvocellular pathway?
sensitive to colour and fine detail -> most input comes from cones
what is the magnocellular pathway?
most sensitive to motion -> most input from rods
describe the pathways from the eye to the brain?
retina
optic nerve
optic chiasm
lateral geniculate nucleus
cortical area V1
how is vision wired?
contralaterally
how is vision contralaterally wired?
the signals reaching the left visual cortex come from the left sides of the two retinas, and signals reaching the right visual cortex from the right sides of the two retinas
what are the three properties of visual neurons?
receptive fields
retinotopy
lateral inhibition
describe receptive fields
the region of the sensory space (i.e. retina) within which light will cause the neuron to fire
describe retinotopy
things that are near to each other in space are processed in cells that are physically near to one another
describe lateral inhibition
a reduction of activity (inhibition) in one neuron that is caused by a neighbouring neuron
useful for enhancing contrast at edges of objects
what is the lateral geniculate nucleus?
part of the thalamus - a subcortical relay for most of the brain’s sensory input and motor output (really fast pathway connected to motor system)
what do cells surround in the lateral geniculate nucleus?
receptive field
responds to differences in light across their receptive field (e.g. light in centre, dark in surround, sensitive)
name the qualities of the lateral geniculate nucleus
maintains a retinotopic map
correlates signals from the
retina in space and time
“is an object moving toward
me?”
provides the early 3D representation of space for action
what is the primary visual cortex [V1] (next stop)?
extracts basic information from the visual scene (e.g. edges, orientations, wavelengths of light)
sends this information for later stages of processing of shape, colour, movement, etc
maintains retinotopy
what do single cell recording by Hubel and Wiesel (1979) indicate?
that some cells respond to simple features (e.g. points of light) and others combine those features into more complex ones (e,g, adjacent points of light may combine into a line)
what does damage to V1 (blindsight) lead to?
a clinical diagnosis of cortical blindness (the patient cannot consciously report objects presented in this region of space)
what are patients diagnosed with cortical blindness still able to do?
make some visual discriminations in the “blind” areas (e.g. orientation, movement direction) - called blindsight)
why can patients with cortical blindness still make some visual discriminations?
as there are other routes from the eye to the brain, the geniculostriate route may be specialised for conscious vision but other routes act unconsciously
what is the functional specialisation theory?
different parts of the visual cortex are specialised for different visual functions
the visual system resembles a team of workers each of whom works on their own to solve part of a complex problem
What do V1 & V2 handle?
early stage of visual perception (e.g. shapes)
What do V3 & V3a handle?
responsive to form (especially of moving objects)
What does V5/MT handle?
responsive to visual motion
What does V4 handle?
responsive to colour
summarise functional specialisation theory
colour, form, and motion are processed in anatomically separate parts of the visual cortex
but evidence comes mostly from studies in macaques, what about humans?
What did Zeik et al’s study find?
V4 more active for coloured than grayscale images (specialised for colour)
V5 more active for moving dots compared with static dots (specialised for motion)
what can patients with cortical ACHROMATOPSIA not do?
see colours because of damage to V4, but often also due to damage to V2 and V3 (despite a fully functioning retina)
What do case studies of patients with achromatopsia indicate and conclude?
intact implicit colour processing
conclude V4 is involved in colour processing but the link between colour processing and V4 is not perfect
what does brain damage to V5/MT lead to?
Akinetopsia (cannot process movement)
what is the binding problem?
as sighted people don’t perceive the colour of things separately to their shape despite the brain processing things separately, scientists are concerned with how the different features bound together to enable to coherent object processing
what is a possible solution to the binding problem?
coherent perception depends on synchronised neural activity between brain regions, which most likely depends on attention
what are the two important visual pathways?
parietal (or dorsal) processing pathway (where)
temporal (or ventral) processing pathway (what)
what is the parietal (dorsal/where) processing pathway?
concerned with movement processing “Vision for action”
what is the temporal (ventral/what) processing pathway?
concerned with colour and for processing “Vision for perception”
what are the steps of object recognition?
- early visual processing (colour, motion, edges etc)
- perceptual segregation: grouping of visual elements (Gestalt principles, figure-ground segmentation)
- matching grouped visual description onto a representation of the object stored in the brain (called structural descriptions)
- attaching meaning to the object (based on prior semantic knowledge)
what is perceptual segregation?
separating visual input into individual objects
thought to occur before object recognition
what is Gestalt psychology?
fundamental principle: the law of prägnaz
of several geometrically possible organisations, that one will actually occur which possess the best, simplest, and most stable shape
assumes a set of rules that operate early in visual processing
what are Gestalt’s laws of perceptual organisation?
a) the law of proximity
b) the law of similarity
c) the law of good continuation
d) the law of closure
what is the faces-goblet illusion?
an ambiguous drawing which can be seen either as two faces or as a goblet
whichever you perceive seems to be in front of the other -i.e. it is the figure
it is assumed that more attention is paid to the figure than the ground
what are problems with Gestalt’s psychology?
segmentation processes aren’t always bottom-up and following the laws of perceptual organisation
most evidence only descriptive, not explanatory
relies heavily on introspection and evidence from 2D drawings
some segmentation clearly occurs via top-down prior knowledge
in which stream/pathway is object information processed?
“what” temporal/ventral pathway
define agnosia
impairment in object recognition (without primary visual deficits)
different kinds of impairments should arise depending on the stage at which object recognition is damaged
what are the two types of agnosia?
apperceptive
associative
describe apperceptive agnosia
impairment in the process which constructs a perceptual representation from vision (e.g. grouping)
seeing the parts but not the whole
associated with lateral occipital lobe damage
what is associative agnosia?
impairment in the process which maps a perceptual representation onto knowledge of the objects functions and associations
seeing the whole but not its meaning
associated with occipito-temporal damage
Describe the case study (Patient HJA) for apperceptive agnosia
bilateral ventral-medial occipital damage
HJA could recognise objects from touch but had a marked impairment in visual object recognition, particularly for line drawings over silhouettes
when shown a paintbrush “it appears to be two things close together but obviously it is one thing or else you would have told me”
HJA had problems grouping or organising information (e.g., recognising any objects presented together with other objects)
describe the case study associative agnosia
visual object agnosia
one of several varieties of associative agnosia
patient LH - preserved ability to copy drawings of objets, but unable to name them or show what they are for i.e. no access of semantics
damage to occiptio-temporal regions
what are some caveats with object perception?
mostly white male western researchers and ppts
west prioritises processing/categorising objects, east asians prioritise relationships between objects and context
never assume that psychological “truths” apply to all of humanity
does damage to the ventral visual stream (what) have impairments on all categories of objects?
some evidence suggests that there are impairments in only one particular category of objects
what can be associated with agnosia for different types of objects like naming faces animals and tools?
lesions to different areas of the what stream (ventral)
faces seem to be personal
what is the issue with faces in object recognition?
face recognition is a within category discrimination - all faces look very similar
other object recognition is between-category
e.g. distinguishing a pen from a cup
possible face recognition has a different type of processing
what is prosopagnosia?
impairment of face processing that doesn’t come from damage to early visual processing
e.g. De Renzi - patient failed to recognise his own family but could do so by voice or clothes
impairment at the stage of matching to stored information
what is the fusiform face area?
part of the ventral (what) stream
responds to faces more than other types of objects in functional imaging experiments
what is holistic processing (concerning face recognition)?
features of faces are processed (and subsequently remembered) less than for other types of objects, like houses
what does Gauthier and colleagues suggest about faces?
they are special because we have become experts at within-category discrimination
claims that becoming an expert at “Greeble” discrimination involves the fusiform face area, as do other types of within category discrimination
name a criticism of categorising faces as special?
not all prosopagnosic patients are impaired on within-category discrimination
what is attention?
attention is the way we select one thing to be aware of out out of a large number of possible things in front of us that we could be aware of at any given moment in time
how does attention help our brains with handling stimuli?
attention reduces the sensory stimuli information overload and determines what we perceive
what are the three paradigms to study the limits of attention?
inattentional blindness
change blindness
attentional blink
what is inattentional blindness?
we as humans overestimate how much of the world we are actually aware of
even very salient (i.e. attention capturing) things can be missed
what are the assumptions of inattentional blindness?
can be concluded easily in healthy participants
occurs more frequently if the display is transparent
depends on the difficulty of the task, the more the primary task occupies attention, the less likely they are to see the gorilla/umbrella
so, attention is a limited resource that you distribute
what is central capacity theory?
a single central capacity (e.g., central executive; attention) that can be used flexibly
strictly limited resources
single pool shared between competing tasks
dual task costs will emerge when two tasks exceed the total resource available
what is the attentional blink?
we can make something invisible by showing it to people very quickly after showing them something else that is important to them