Cognitive Psychology Flashcards
What is Decarte’s error?
Thinking that the brain and the mind are two separate phenomena. That there is a difference between what is physical and what is psychological. They are actually the same thing
Describe Marr’s Levels of explanation
- Computational level: What the system does and what the purpose is
- Algorithmic/Representational level: What processes does the system use, what representation does it use
- Implementation/Physical level: What does the system look like. How is it physically realised?
Theory on where thoughts come from
Every decision/thought is based on what happened before it. There is no origin; everything is a consequence of environment
5 techniques for measuring cognitive activity
- Behavioural paradigms
- Psychophysiology
- fMRI
- Electroencephalography (EEG)
- Transcranial magnetic stimulation (TMS)
What are behavioural paradigms?
For example, measuring reaction times
What is psychophysiology?
For example, studying decision making based on an eye tracker, or by measuring skin conductance
What does an fMRI measure?
Blood Oxygen Level Dependent (BOLD) signal
Blood flow correlates with brain activity
How does an MRI work?
Giant magnet (cooled by helium) creates strong magnetic field
Magnetic field aligns hydrogen atoms
Scanner transmits radiofrequency (RF) waves
Causes hydrogen atoms to change spin direction
When they change back, they release electromagnetic energy
Energy detected by detection coils
Tissue type can be inferred by how quickly the energy is released after the RF is turned off
Pros of fMRI
Sensitive
High spatial resolution
Can scan the entire brain - even deep layers
Cons of fMRI
Low temporal resolution - paradigm has to either be slow or jittered, which can affect behaviour
High type 1 error rate
Provides evidence for correlation, not causation
How are fMRI scans compared?
Mass Univariate Approach
Brain image divided into VOXELS
BOLD signal compared on voxel-by-voxel basis, like running a t-test between every voxel
What is Electroencephalography?
Many electrodes placed on scalp (scalp cap)
Electrodes measure event-related potentials
Same event repeated many times
Calculate average signal
Pros of EEGs
High temporal resolution
Cons of EEGs
Low spatial resolution
Provides evidence for correlation, not causation
Potential for Type 1 errors - not as high as fMRI though
Can measure cortex but not deeper brain areas
What is transcranial magnetic stimulation?
Metal coil used to generate a magnetic field
Changing the magnetic field induces a current (electromagnetic induction)
Disrupts part of the brain - observe if this has an affect on a certain behaviour
Pros of TMS
High spatial resolution
High temporal resolution
Can make casual inferences about areas of brain involved in behaviours (better than correlation)
Cons of TMS
Requires precise hypothesis about area and time of brain activity
High chance of a type 2 error
What is neuropsychology?
The study of cognitive and behavioural effects on the brain following injury, stroke, Alzheimers, botched surgery etc
Give 4 examples of neuropsychological symptoms
Attention neglect
Cortical blindness
Frontal lobe disorder
Broca’s/Wernickes aphasia
What is attention neglect?
Caused by a lesion to the right parietal cortex
Will ignore part of visual field e.g. only eat food off one side of plate
Weird thing is they can still see the stuff they are ignoring
What is cortical blindness?
Caused by lesions in higher visual cortices
Experience blindness - but will avoid objects in a crowded room, suggesting they can still see?!
What is Frontal lobe disorder?
Caused by lesion to frontal lobe
Drastic changes in personality and behaviour
Often do not know where they are meant to be
Can’t plan more than a few minutes in advance
What is Broca’s aphasia?
Problems with speech and language
What is Wernicke’s aphasia?
Difficulty understanding language
Can speak but it often doesn’t make sense
What are neuropsychological test batteries?
Used to assess neuropsychological ability following a stroke/injury
Done repeatedly, to see if a condition is getting better/worse
Test if someone is fit for work
Need to have a lot of population data to compare the results to
