2xa3 chapters 1-3

Beginning in the 1950s The scientific study of how the mind, encodes, stores and uses information; the study of cognition
Can also be defined as objective measures of behaviour to test how the mind encodes, stores an uses information about the environment
Ranges from the most mundane scenarios to most extreme. Cognitive psychology aims to understand mental representations and the computations performed on them

Perception
Attention
Memory
Reasoning
Decision making Eg) A referee, needs to be able to see players and the soccer line. You need to pay attention to players close to ball as well as ignore crowd and remember every rule of the game and be able to act on it

In research it is hard to understand cognition in scenarios such as the ones above, so we often use mundane, well-controlled scenarios
You can observe people's behaviour in real-world scenarios (are lab observations applicable in the real world?)

Encoding example: Basketball players passing ball to each other, don't see gorilla
Storage example: False memory implantation: telling someone they got lost in a mall as a child and they believe it even though they probably didn't
Using information example: Trolley will fall off of bridge with 5 ppl, will you throw someone onto track to save ppl at the cost of one?

Mental life is all about information - both internal and external sourcesInternal would be like thoughts, emotions, knowledge

Mental representations are the encoded and stored information about the environment
Mental computations are the actions performed on what is encoded and stored

Human cognition queried at least as early as the ancient Greeks
Plato proposed that humans are born with every piece of information that exists in the world so every time we think we are learning something new, we are just recalling something we already know There is research that proves that certain processes are innate
Aristotle claims that those who educate children should be praised more than those who just give birth, because they teach them the "art of living well" - rather than those who just gave birth

Ernst Weber in 1830, discovered the "just noticeable difference" - coined later as Weber's Law

the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)

Gustav Fechner (1850) - coined then expanded Weber's law and established field of psychophysics Expanded weber's law to formulate fechner's lawPerceived intensity is proportional or actual intensity

(1850s-1860s) proposed the idea of an unconscious inference - based on measurements of reaction timesIf your hand is stroked by a feather, it will activate something in your hand and will send a signal to your brain Signal takes time to react - seen by reaction timeIbn-al-Haytham made the same conclusion 1000 years earlier

(1860s): proposed that the speed of higher mental processes could be similarly measured as the speed of nerve transmission Eg) Class holding hands, squeeze next persons hand when yours gets squeezed, might take about 30 secsIf you do this with feet instead of hands, it will take longer because signal has to travel a longer distance Limitation: Assumed that processes don't happen at the same time- but we know that multiple processes do occur at the same time

In 1879 he used reaction times and introspection to research the structural components of mental life (structuralism) His student Edward Titchener brought structuralism to the USA

In 1885, he demonstrated that higher order mental functions (eg: memory) could also be measured experimentally. he discovered the forgetting curve.
Ebbinghaus discovered the forgetting curve by making a list of gibberish words and memorized them and tried to recall them

Opposition to structuralism led to at least 2 different schools of thought. Gestalt psychology and Functionalism

Gestalt Psychology: psychology depends on percepts that are the greater than the sum of parts

Functionalism: Study of psychology should be the function of the mind (William James) Heavily influenced by Darwin's work on natural selection Based more on the small bits (different functions of the brain, small building block), not the bigger picture Formed the basis of behaviourism by focusing on adaptation

Understanding the mind had to be achieved through purely objective measures Not talking about what is happening in the brain and abstract ideas Objective measures = behaviour Used Pavlov's classical conditioning as the basic unit of learning Skinner's operant conditioning also became important after Using reinforcement or punishment as outcomes to increase or decrease the likelihood of an action and its repetition

Introspection involves observing your own mental experiences Would be considered too subjective today
Increasing numbers of researchers felt Behaviourism could not explain psychological experiences
The public loved the idea of behaviourism because they believed that reward/punishment could shape a child

Noam Chomsky (1959) criticized Skinner's description that children's language development occurs via conditioning

Edward Tolman (1930), demonstrated that reinforcing is not required ro learning Ran rats through mazesOne group received rwwards each time they completed the mazeSecond group got no rewardsThird group went unrewarded for 10 days, then got rewards after Rewarded group learned maze fastest, other two groups wandered aimlessly Directional experimentRats placed at south end point rewarded for turning right. When same rat placed on north end, they turned left displaying that they built a cognitive map and It's not just them reacting based on motor movements

Claude Shannon (1984) demonstrated the nature and processing of info itself can be studied and analyzed without consideration of the actual content of the message (0s and 1s alongside rules/algorithms to interpret different patterns of 0s and 1s) His approach laid the foundation for the information theory, which focuses on how info is coded, stored transmitted and reconstructed

George Miller (1956) identified the amount of information people could store (7 +/- 2). George Miller (2003) outlines the pivotal moment on Sept 11th 1956 that triggered the start of cognitive science

William Hamilton claimed that if you throw marbles on the floor, you will find it hard to view more than 6 without confusion.

Early-selection model
Filters message before incoming information is analyzed for meaning

Psychology is modelled after physics. Urge to treat psych in the same rigor as physics
Strong desire from researchers to return to studying the mind
Cannot understand everything just by observing behaviour, like you cannot tell what someone is thinking if you just see them sitting there

The focus of cognition ended up focussing on mental processes and events instead of the stimulus-response condition
ExamplesThe process of knowing rather than merely responding to stimuli How the mind structures or organizes experiences How and individual actively and creatively arranged stimuli received from the environment
Cognitive neuroscience is distinct but sometimes inseparable from cognitive psychology

Not all emotions can be studied in an experiment
People differ in how they describe emotions
Not everyone reacts emotionally to the same stimulus the same way

Historically, emotion was treated as distinct from cognition Emotions were often considered annoying and useless
However researchers are realizing that they are more intertwined wit our cognition than we thought

If something makes you anxious, don't approach that thing
Source of info, rather than noise

Emotion IS cognition
Emotion is a result of our previous experience with a certain stimulus

Done with a baby, a toy was put behind a barrier and then a second toy was put behind a barrier then one toy was removed
Baby was surprised because baby expected two toys behind barrier when it was removed
Displays that babies have some innate understanding of math

he mind exists distinct from brainody
Cogito, ergo sum - "I think, therefore I am"
Mind using body as machinery
Little person sitting in your brain

The mind is a product of the brainody
Doesn't exist without brain and body
The mind is the experience provided by neurons firing
Basis of cognitive neuroscience
Kind of a required belief, because if the mind was external we wouldn't really be able to understand it
According to Donald Hebb, "behaviour and neural function are perfectly correlated...one is completely caused by the other"

Different parts of brain serve different functions
Scientists used to think that the brain was "homogenous" - but now we know different parts have different functions

Like damage to the fusiform gyrus leads to prosopagnosia (face blindness) - they can function normally for everything else except recognizing faces Or Hippocampus damage leads to memory loss - they can recall old memories just fine but not form new ones
Seeing someone you recognize is your fusiform gyrus and hippocampus + other memory network working together

Brain composes of neurons and glial cells
Neurons transmit signal bia action potentials (within a neuron) and neurotransmitters (between neurons)
Synapses are plastic and are affected by learning and experience
Neurons consist of dendrites, soma (cell body) and axon. Glial cells support neurons by providing nutrients and structural support

Action potentials (electrical signals that pass infromation) occur in an all or nothing fashion
Neurotransmitters are chemicals at the end of axons which is how neurons communicate
There are about 100 trillion connections between individual neurons (via synapses)

Through interfering with signal propagation along the axon
Through blocking neurotransmitter release between neurons

Sensory neurons receive information from sensory receptorsThings like carrying flavour and taste
Motor neurons control motor output (action and speech)
These and other neurons form networks to integrate information for various goals

Left and right hemispheres Corpus callosum (bridge of axons) that connects one side of the brain to the other side Both sides look very similarLeft side more involved in language Right side more involved in spatial processing Left side controls right side, right side controls left side

Can see consequences of your hemispheres not working together

Outer layer of brain is cerebral cortex Grooves are called sulci Ridges are called gyri

FrontalThinking and planning Larger in us than other primates Primary motor cortex
ParietalVisual/spatial processingHas somatosensory (touch) cortex
Temporal More complex visual processingLanguage areas
OccipitalPrimary visual processing

Ability to pinpoint where neural activity occurs

Ability to pinpoint when neural activity occurs

amount of impact a method has on an individual's brain Like stimulating brain regions with magnet around head Can involve planting electrodes which requires opening the skull with surgery

Studying the behavioural impact of brain damage
Damage can be natural or unnatural
Need to identify overlapping regions. Eg: Regions of areas identified this way Broca's areaBroca was studying patient who would only repeat the word "tan" over and over again, upon death he learned there was damage to this area of the brain. Allows you to look at what part of brain is affecting behaviour (after accident or mishap)

Looking at overlap between different brain damage of different patients allows you to determine what processing happens where

Mapping brain mechanisms to behaviour is possible because of functional specializationBroca discovered a patient that could understand language but not speak it Wernicke discovered a patient that could speak but not comprehend language

Brain damage is common due to stroke In a stroke, blood supply toa brain area is interrupted or severely reduced which kills neurons

However there are flaws, like brain lesions are imprecise and generally affect nore than one region, therefore it makes it difficult to systematically associate patterns of brain damage with specific functions such as face discrimination
Studies conducted with patients aren't always easy to conduct because brain damage can impair several functions
Clinicians also need to prioritize patients rather than treat them for scientific gain
What would be the most invasive out of...
- Recording brain activity from scalp electrodes
- Stimulating a brain region using magnetic fields from a magnet around the head

Stimulating a brain region using magnetic fields from a magnet around the head because invasive refers to brain impact, not rest of body

tudy of direct electrical activity of neurons measured by inserted electrodes
Going in with one electrode into one cell (time consuming)
Electrode however can pick up signals from multiple neurons which computer algorithms can isolate individual signals. Highly invasive but painless because you're in the brain. This method has spatial and temporal precision

Hubel and Wiesel won Nobel prize for recording from (cat) primary visual cortex Tried to get cat's neurons to fire above baseline Cats saw lights when they were on break and neurons fired above baseline

All neurons have baseline firing rate, uninteresting stimuli won't change baseline firing rate, interesting stimuli will most likely increase firing rate
Goal is to change the firing rate of neurons
Firing rate will change in comparison with the baseline

Intracranial recordings used to localize origin of seizure activity Electrodes attached to cortex. Highly invasive and patients are heavily medicated
Can look at more region of brain

Has revealed highly selective neurons (Jennifer Aniston neuron) Called this because she was the first example they showed Revealed activity in certain part of brain If someone hasn't seen Jennifer Aniston, they won't have a Jennifer Aniston neuron so they may have activation if shown a pic of their grandma

Highly invasive and patients are heavily medicated
Can look at more region of brain
A disadvantage is that the placement of the electrodes is clinically determined rather than guided by research hypothesis

More common that EcoG and electrophysiology
Recording neural activity at the scalp. Noninvasive - but subject might get irrirtaed with having to sit still for a long time. High temporal resolution but poor spatial resolution because it's a general idea of whats going on
May require shampooing after because of gel
Usually possible to distinguish where activity is occuring (anterior or posterior of brain)

Lots of layers between neurons and electrodes because of hair and skin
If you see activity, it reflects activity from millions of neurons (spread out across neurons and strong enough to make it past the skill and skin to electrodes)High temporal resolution because Good at telling you when activity occurs

Event related potentials (ERPs) The EEG responds to a specific stimulus/task (ie: event)
Imagien you hav a EEg cap and someone flashes you a pic, your brain activity can be measured and the small bits of measurements can be put together to form an event related potential. The pattern in response to a stimulus or task is called an event related potential

Above is an event related potential for human face as pic and watch
Typically every 2ms you get an influx
P100 for face and watch is same
N170 dip is larger for faces than watches and strongest in right posterior occipital lobe
Suggests that after 170ms of seeing a face, your brain has engaged in face specific processing
Even a headless body would get a bigger response than a car
The Positive and Negative has to do with how the EEG is recording - not much to do with brain activity itself
EEG activity works in dipoles, seeing negative activity on one side would mean seeing positive activity on the other and vice versa
Time 0 represents when stimulus is shown
If you're a bird expert, you'll see a larger N170 than others when you see a bird, same with if you're a car expert

Measures the blood oxygen level dependent (BOLD) signal Increases with brain activity because neurons need oxygen after being active
Tracks blood, where blood rushes indicates where activity just occurred in brain (blood replenishes nutrients lost)
Measuring brain activity indirectly through blood. High spatial resolution but low temporal resolution
Subtraction method allows localizing activity related to task/stimulus. Cannot have any metals on you (limitation) Uses powerful magnetic field and brief radio pulses. Significantly better spatial resolution than any other noninvasive method to study brain activity

Compared to MRI, this says more because MRIs just show structural images of brain - says nothing about activity. Allows for functional brain mapping Identifying which part of brain does what. MRIs just produced images of slices of the brain

Easy to make a reverse inference which we should always avoid You can look at data make assumptions so you need to be careful with things like the subtraction method If you're only studying perception of faces and cars, you cannot make assumptions about those areas and how they'd perceive a house
You need to give the subject a task to do with the faces - like asking them to remember them because they will be tested later (same for EEG)
Hard to make conclusions with a limited number of subjects - FMRIs are expensive but you need multiple participants. indirect study of brain activity. Temporal resolution is poorer for fMRI than EEGs

Looking at first pic, we can't tell which part of brain is involved in face processing so we take another set of images and compare the active brain regions to deduce where face processing area of brain is (subtraction method)
Look at overlap, you can deduce which areas are involved in general processing versus faces
Activity higher for faces alone reveals brain regions important for face processing, which falls in the right fusiform gyrus, known as the fusiform face area
Activity higher for scenes alone is in a separate region in the parahippocampal gyrus or PPA

The FFA and PPA are examples of functional brain mapping Allows clinicians to see what happens when a brain area is damaged Someone could argue that knowing where function are located in the brain doesn't tell us how the brain works
Brain mapping establishes regions of interest for further testing of brain and cognitive functions
For FMRIS you cannot make assumptions like if the FFA is active, then that doesn't have to mean that someone is looking at faces

Has been around for longer than tCDS
Temporarily disrupt brain activity using focal magnetic pulses targeted over different areas of the scalpCoil causes brain activity
Correlations doesn't equal causation. So we can use TMS to find cause. TMS over the right hemisphere occipital face area impairs visual
processing of faces but not objects or bodies
Has good temporal resolution
Doesn't have very good spatial precision and reach, it can only disrupt activity 3cm within the scalp
Has a small risk of seizures and discomfort

Instead of causing Aps, this simply increases or decreases firing rather than causing it
Can promote learning
Done over dorsolateral prefrontal cortex improved ability to briefly remember and manipular info (working memory), while being done over motor cortex didn't show improve
Causes activity (stimulation) vs tCDS that is a modulator - influences how neural activity occurs

EEG (Electroencephalography)

fMRI has good spatial resolution but low temporal resolution

TMS

Brain lesions

Single units

Behavioural genetics is the field that attempts to link behaviour (phenotype) and genes (genotype)
Intelligence and executive function are heritable to a certain extentEg) identical twins raised in different environments can show a strong correlation in intelligence

Environment influences how genes operate without changing the genes themselves The field that studies this is called epigenetics

Gene manipulation can be done using knock out - which is done by rendering a gene absent or unexpressed Can lead to memory impairment or generation of false memories

Constructive nature can explain why we perceive the dress differently
Materialism can predict that "dream machines" are possible

It is the ability to recognize and interpret information from the senses. We know it is constructive because of our retina and visual illusions. We interpret neural activity from what is produced through light input
Part of eye that has no photoreceptors (opening of where all photoreceptors join and go into brain) "blind spots"
Our brain can reconstruct visual information with the two blind spots from both eyes
Illusions support the idea that perception is constructive

The reason we see dresses as different colours is because we have different assumptions about the lighting of the room Well lit room: Blue and black dressDimly lit room: White and gold

This is top down influence on perception We make an assumption about what is going on and then perceive Memory establishing a category would count as top down information rather than the distinguishing of light orientation and retinal signals to the brain This is because the light that is oriented a certain way is what is affecting our perception - we cannot assume that because it is what it is

Sensory info from each sensory system from receptors to the primary sensory cortex for the sensory system. Info flowing gets processed by sensory system. In the case of vision, it is the exact activity of the rods and cones that helps you determine what you see. Bottom up processing supports the idea of unconscious inference

Knowledge and expectations that influence and enhance our interpretation of sensory input. Both context and experience play an important role in shaping perception

Predcitive coding predicts what input the eyes are about to receive. Seeing a blurry image of what yo know to be a bathroom sink, and then seeing an object on the surface can make you think that you are seeing a hairdryer, but that same ambiguous object in a tool setting can make you think its a drill

Visually assigning the elements of a scene to separate objects and backgrounds.
Lines that separate the girl from the background are the same lines on her vest, but a machine cannot understand the differences between the edges and it would interpret the image as a mess like on the far right
This is where top-down processing is useful

Requires determining which side of a boundary belongs to an object (the figure) and which side belongs to the background (the ground) Our mind uses rules such as symmetry, enclosure, convexity and meaningfulness to separate what we see as the foreground and the background

As we get older, it gets harder to distinguish between a foreground and background because we don't use cues as effectively as younger people

Views of objects are often partially blocked by other objects which is resolved by amodal completion. We know there is a firetruck behind the tree, but if we isolate only the parts of the firetruck we can see, it doesn't really look like a firetruck. If someone asked you to redraw the scene, you would make an extension of the image beyond what you truly see.

The mind to solve the inverse projection problem and we need to rely on our knowledge of binocular and monocular cues.
Image projected on retina is a 2D image
Need to rely on top down processing
Different visual stimuli pass different images down to your retina

Both monocular and binocular depth cues are needed.Binocular depth cues help with seeing close up objects with both eyes because if you looked at them from only 1 eye, you'd see different thinks. With monocular depth cues, you can perceive things the same from each eye and it usually applies to things further away

3D glasses are designed to filter out different lights for each eye
If you take your glasses off the screen looks blurry
Binocular disparity: When something is close to you, a different image is going into each eye 3D movies use binocular depth cues

Despite retinal image varying drastically we recognize objects at varying viewpoints, sizes at different distances and colours and brightness in different illuminations. - Object, size, colour and lightness constancies

Trouble recognizing objects and matching to correct categories and labels. People may be born with it but it is mostly caused by brain damage. Mostly only a visual problem

a form of visual agnosia marked by the inability to recognize simple shapes such as circles and triangles and cannot redraw a model of something placed in front of you. (Impaired early vision)

a failure to understand the meaning of objects due to a deficit at the level of semantic memory. (Impaired late vision, can redraw model but not name it)

We match images to representations that are like 2D pics or templates. Series of images that we accept to represent a shoeWhen we see a new shoe from its backside, we have a template that helps us recognize what a shoe is because we have a template for the back of a shoe
Template for numbers and what they should look like

Models that represent objects as sets of 3D parts standing in spatial relationships to each other.
Essentially building blocks with rules on how they go together
Suggested 36 shapes that can account for millions of objects
A bit more inclusive in the sense that you don't necessarily have to have seen something to recognize it (like the template theory)

Faces are unique objects in that we humans see, distinguish and engage with them all the time. Seeing faces increases activity in the fusiform face area (FFA)

Masking has somewhat negatively affected FFA, but not that negatively because we mostly use eyes/eyebrows for facial recognition

Used subtraction method in study above to determine how the brain responds to faces
People who have gained expertise in something beyond faces, are just as good with differentiating those individual things Like a bird expert would recognize a bird they saw a day ago Their FFA is more active to birds. Possible anomaly: Car experts didn't have the same FFA activity for faces

One idea is that expertise leads to holistic perception, meaning that a whole thing would be more informational that parts of it (including the relations of the individual parts to each other). Due to this, more holistic processing should be associated with better identification abilities for that stimulus class . If you're using mechanism A to recognize B, the stronger mechanism A is the better you should be at recognizing B