Cognitive, WEEK 1

Question 1

What is cognition?

Answer 1

mental action/process of acquiring knowledge through thought, experience and senses

Question 2

What is cognitive psychology?

Answer 2

Scientific study of thought + experience (how the mind generates thoughts and perceptions and how our thought impacts perception)

Question 3

What is the information processing approach

behaviourist

Answer 3

• Explains how cognition works + is comparable to how a computer works
• Stimulus from world (e.g. noise) gets processed in stages > pay attention to the stimulus, perceive it, process it (cognition) and then decide what want to do + respond, usually with a motor action (do we do anything about the stimulus?)
• Processes happen sequentially > “stimulus response machines”, humans are just responding to what is in the environment (bottom-up)

Question 4

What does the information processing approach assume?

Answer 4

• Serial processing: Only one step happens at a time in order > info gets processed by one module then is sent to the next and cannot go backwards
• Bottom-up processing: processing caused by a stimulus (enters from bottom of your brain and processed to the top > external stimulus triggers processing)
• Stimulus is the input and info from it is based entirely from the stimulus, nothing else happening in the brain is relevant to it > stimulus processed sequentially = output

Question 5

Criticisms of information processing approach

Answer 5

• Doesn’t allow for parallel processing > this is where we can do tasks simultaneously on different processors (humans can multi-task + is unexplained by the app)
• Ignores top-down processing > influence of the individuals mind, prior knowledge, goals and expectations about the world. > this beh approach oversimplifies the processing of info

Question 6

What are representations?

Answer 6

• Everything we see and experience in the world is also represented in our brain
• E.G: if a person watches a person walking a dog (person has an experience of seeing the dog), there must be a representation of a dog in the persons brain (what a dog is) > the firing of neurons/brain cells represents the dog (when you look at a dog, neurons are firing together and that is the experience of the dog)
• If you can have a conscious experience of something, that must be represented in your brain somewhere in the firing of neurons as that is the experience.

Question 7

How can neurons represent complex information?

Answer 7

• Some neurons have preferred stimuli (e.g. respond to a certain colour more than others) > more likely to fire when faced with preferred stimuli than others
• Quiroga (2012) looked at patients with implanted electrodes in medial temporal cortex > found when showing a ppt many kinds of stimuli, a picture of Luke Skywalker led to neuron firing to increase compared to other stimuli > can explain how representations form
• An individual neuron doesn’t necessarily represent a whole concept, it is likely to overlap with other neurons.
• Referred to as “Grandmother cells” sometimes > idea there is a cell in your mind which fires when you think of your grandmother

Question 8

Rate vs Temporal codes

Answer 8

• Shows how information can combine to form representations of things (e.g. dog/Luke Skywalker)
• Rate coding: In each neuron, the information which it represents is represented in how fast it fires. (whether it fires quick or slow depends on the info it is representing)
• Temporal coding: Rate at which neurons fire may not be as important as the synchrony of several neurons firing together (when neurons fire together, you have a representation of Luke Skywalker + when they stop firing together, the person is no longer thinking of Luke Skywalker)
• Important in the binding problem

Question 9

Binding problem

Answer 9

• refers to the fact we are able to bind different features which are represented by different neurons + pathways > e.g. when we perceive a moving blue ball we do not process it separately as being blue, a ball and moving, we process it all as one suggesting there must be a neural mechanism allowing info to “bind”

Question 10

What is experimental cognitive psychology?

Answer 10

• Studying behaviour in controlled laboratory settings using manipulations of stimuli given to participants. Done to manipulate the way participants think and the type of mental processes they use then measure their behaviour (output) > measures what happens in the brain indirectly by observing behaviour
• Instead of “brain measures”, cognitive psych uses behavioural measures such as reaction times or accuracy (how quickly can people make decisions?)
• Using the reaction of the participant, we can infer what mental processes occurred before the decision was made

Question 11

Inference

Answer 11

refers to filling out missing gaps using information which is already known. E.g. you see a woman with a nappy in her hand and vomit on her top, you may infer she has a child

Question 12

Stroop test (e.g. of experimental psych)

Answer 12

• Stroop test is designed to see if reading is automatic or not. (meant to read the colour of the word written (which is also a colour)
• Typically, RT’s are quicker for words that match the colour than for words which don’t. If you see the word red written in green, you process red first because you have automatically read it and processed it > red interferes with ability to press green.

Question 13

Strengths & limitations of experimental cognitive psychology

Answer 13

+ Successful in generating theories about cognition which can then be tested in other methods like neuropsychology
+ Contributed to making Psychology an empirical science > have data which can be measured accurately and more quantitative than other measures
- Lacks ecological validity: can we generalise the stroop task to real life? RT to stimuli which we would not face in everyday life > does cognition work the same way in everyday life as in experiments
- Lacks face validity: we are measuring cognition indirectly using RT’s and accuracy, how do we know what we are indirectly measuring actually measures cognition
- Do psychological concepts even exist? can’t assume something exists just because it is named (e.g. attention).

Question 14

What is cognitive neuropsychology?

Answer 14

• Study cognition in patients with brain injuries > study the way in which cognitive + thought processes, perception etc have changed in people with brain damage.
• Goal is to find out which part of the brain is most responsible for which cognitive concept (e.g. if a patient has damage to their parietal lobe + has problems with orienting attention, we may infer that the parietal lobe is associated with attention) > can use this to test the area and its relation to attention

Question 15

Limitations of cognitive neuropsychology

Answer 15

• No baseline: don’t know the ability of the patient before their brain injury, could already have a problem with attention e.g > have to make assumptions about what their cognitive abilities were before their injuries to understand what has changed > cannot be completely certain
• Generalisation: Is the same injury going to cause the same psychological deficit in other people? certain parts of your brain are more likely to be damaged due to injuries causing them while others are rarely damaged > if someone gets brain damage to a part of the brain nobody else has and has certain affects, we won’t know if this can be generalised to others
• Modularity: assumes brain is divided into modules where one part of the brain deals with language, another with attention and so on. More likely the brain is a distributed system where processes occur across multiple areas rather than just one. (e.g. attention is likely to involve communication across multiple parts of the brain)

Question 16

What is cognitive neuroscience?

Answer 16

• This is where we relate brain structure and brain function to cognitive processes. Do this by recording brain activity while the person does cognitive tasks (similar tasks to experimental cog)
• If a certain area is more active when doing an attention task, the area may involve attention

Question 17

What is electrophysiology?

Answer 17

• Electrophysiology: the measurement of electrical activity within brain cells
• Types of electrophysiology include single-cell recordings and EEG’S

Question 18

Electrophysiology: single-cell recording

Answer 18

• Looks at activity at a very basic level. A very small electrode implanted in animals or humans which record from one neuron + record output of that neuron > typically done in animals due to ethics
• Can record neural activity from within axon (intracellular) or from outside axon membrane (extracellular) depending on what we want to measure.
• Occasionally can do intracranial (inside the head) recordings with people who are having surgery for epilepsy > in this process neurosurgeons insert electrodes in different parts of the brain where they think is associated w/ epilepsy > record activity in brain which helps identify part of brain needing to be removed > during this patients get involved with cog psychologists + tasks

Question 19

Electrophysiology: Electroencephalography (EEG)

Answer 19

• Series of electrodes put on the scalp which records electrical activity which is generated by a large number of neurons firing together > when groups of neurons fire, they produce an electrical voltage which is detectable outside the head > non-invasive
• From EEG’s we can get event-related potentials. An ERP is the average of the EEG in response to the same sort of stimulus. ERP gives a more accurate representation as in the brain several things can be happening at the same time which could influence one EEG, so taking several EEG’s and finding the ERP is more accurate + representative
• ERP’s can be used for psych experiments. e.g, compare the ERP of someone paying attention to stimuli and not paying attention. The difference between ERP’s can be observed and can infer that information you are paying attention to is processed differently to information not being paid attention to if the difference is clear > can tell when certain cognitive processes may occur

Question 20

Strengths and limitations of EEG/ERP

Answer 20

+Very good temporal resolution real time measurement of activity of data > record data as fast as the neuron fires > high temporal resolution
+ Quite cheap and portable so it is easy to get ahold of and can be set up easily
- Poor spatial resolution: (how well we can tell where something happened in the brain) > for any given voltage recorded from the brain, there are an infinite number of possible origins for an signal recorded at the scalp > problem because if we see electrical activity under an electrode, it doesn’t mean the activity is from under where the electrode was, it could be from anywhere in the brain
- EEG’s/ERP’s tell a lot about when cognitive processes happen but not about which parts of the brain are responsible for them

Question 21

Magnetic Resonance Imaging (MRI)

Answer 21

• MRI works by putting someone in a very strong magnet > MRI with a very strong magnetic field is between 0.5-7 Tesla (T). 1 tesla = 10,000 Gauss > magnetic field of the earth is 0.5 Gauss
• In the brain we have protons in water molecules which spin. When put in a powerful magnet, these protons spin and line up with direction of the magnetic field (in MRI scanner, the magnetic field goes through the hole in the middle)
• The MRI then disturbs the spin of the protons by firing short radio frequency pulses at the head > hitting a proton with radio frequency makes the proton wobble. The amount it wobbles changes the magnetic field being generated by protons
• Using this we can measure how long it takes for those protons to stop wobbling because we know different types of tissues will take a different amount of time to stop wobbling and go back to lining up with direction of magnetic field (to relax). > MRI tells us only about brain structure + not functions > convert FMRI for functions
• We can use this to create images of where we think the tissues in the brain are for the person based on how much time it takes for the protons to face in line with the magnetic field after turning off the radio pulse.

Question 22

Structural MRI & Diffusion Tensor Imaging (DTI)

Answer 22

• Structural MRI: Can use this to look at the outside of the brain as well as virtually slice through the brain to see sections of the inside > high spatial resolution, can see where things are
• Structural MRI DTI: works by measuring how water diffuses across white matter bundles in your brain (bundles of axons in your neurons). In white matter bundles, water diffuses differently out of axons than it does out of other aspects of tissue in your brain. In DTI, if you measure the way water is diffusing, you can produce maps of where these connections are in the brain, how strongly connected are they + how do they form? > measures relationship between cognition and connections in the brain
• DTI wants to see the structure of white matter

Question 23

Functional Magnetic Resonance Imaging (FMRI)

Answer 23

• FMRI doesn’t measure neurons directly > FMRI measures the BOLD response. BOLD = Blood Oxygenation Level Dependant Signal
• Neurones which are active (firing) need oxygen (if neurones are working hard, firing more, they need more oxygen) > brain starts supplying oxygen to the areas which need it more, eventually produces an “overshoot” in oxygenated blood, where too much is supplied before getting used up
• Oxygenated blood causes less magnetic field disturbance than deoxygenated blood > oxygenated blood relaxes differently to deoxygenated blood > we use FMRI not to detect structure of the brain but to detect where the oxygen is being sent and used in the brain > can infer indirectly that if part of the brain is using more oxygen, it may be because it’s neurons are firing + more active > if it is firing a lot it may be involved in a cognitive process

Question 24

Subtraction Logic

Answer 24

• We have to design an experiment which isolates what we want to look at such as a cognitive process like memory (subtract what is happening in the experimental group from the control group). To do this you need to make sure the only difference between the groups is the cognitive process.
• Subtraction logic is needed for cognitive exp
• Important because when remembering the words, other things are happening in the brain such as visually seeing the words, paying attention to it, pressing a button to say you remember it (motor) > this is picked up by the FMRI scanner > we need subtraction logic and to compare to a situation which removes these other things (aside from remembering) so we can see the true impact. By pressing a button for words remembered and forgotten, the extra variables are included which enables better comparison

Question 25

Brain Stimulation Techniques

Answer 25

Other methods discussed are correlational (measuring brain in response to a stimulus)

• if we want to achieve causality > brain stimulation techniques are good.
• To know if a particular part of the brain causes a certain cognitive process, we need to change the activity of that part of the brain and show this changes behaviour > causal evidence

Question 26

Transcranial Magnetic Stimulation (TMS)

Answer 26

• TMS coil is put on a persons head, this is a electromagnet producing powerful + focal magnetic fields > on someones head this produces magnetic field that go inside their skull
• When this is done, depending on the type of magnetic field produced, you can either induce electrical activity in the cells it passes through (making neurons fire) or stop neurons from firing by overloading them which stops it firing for a while (like a brief brain injury) > if you can see a change in behaviour by stopping neurons firing, there is causal evidence

Question 27

Advantages + limitations of brain stimulation

Answer 27

+ Causal method
+ Mostly non-invasive and should be painless for most people
- Stimulation to the brain is very weak because it has to happen from outside the head and be safe and painless, this causes the effects to also be quite weak > hard to tell if there is a difference
- TMS could induce a seizure in those who suffer epilepsy > not everyone can be recruited to undergo TMS

Question 28

Limitations of cognitive neuroscience

Answer 28

• Very expensive, costing millions of pounds and invasive > using an MRI for a few hours costs 100s of pounds > due to the expense, samples tend to be very small which may mean results are often less generalisable
• Not testing theories > in literature there is considerable emphasis on measuring brain effects but there is not as many testing theories which it should be so we can test predictions of when or how something happens.
• Does cognitive neuroscience really help us understand cognition? working backwards from the behaviour seen then using MRI or EEG etc to try understand behaviour > does this actually help our understanding of cognition? how a particular experience or thing is represented in the brain?