Pscyhological Methods and Inferences Flashcards
What is epistemology
Philosophical study of how we know things.
Basis for belief:
- authority such as “mum told me”
- logic such as cogito ergo sum (I think, therefore I am)
- observation/evidence based research
What is deduction?
Process of elimination - as long as the premises are true, the conclusions will be true
Valid arguments do not guarantee truth conditions
testing an existing theory
What is induction?
Method of reasoning where individual facts are used to give a general rule or conclusion
conclusions from induction may be true, but are not guaranteed
developing a theory
what is inference?
the act of coming up with the conclusion based on evidence/observations
What is verificationism
Seeking out evidence that agrees with our theory, of which there may be plenty
why does verificationism not work?
a single piece of contradictory evidence could disprove theory
therefore, we should seek to disprove theories in order to make better ones - use CRITICAL perspective
e.g., “my car starts every day, therefore it is going to start tomorrow”
What is falsification?
testing theories by trying to falsify (disprove) them
good theory = makes it clear what evidence would falsify it
bad theory = not falsifiable, e.g., ‘there is a Loch Ness monster’
2 examples of neuroscience methods
- Reaction time
- Neuroimaging
what are neuroscience methods for?
- help identify how cognitive algorithms are implemented in neural tissue
- help rule out certain algorithmic theories of cognitive function
Robertson and Kim (1999) - Reaction Time Study
Flash prime at one end of line, then target at other end.
task: detect yellow target as quickly as possible
optical illusion used to make one line look longer than the other. when experiment was done on “longer” line, reaction time was increased
therefore, brain moves attention in an internally constructed world, rather than on physical features alone
What is spatial resolution
Number of pixels (2D) or voxels (3D)
or
measure of the smallest object
What is temporal resolution
Ability to distinguish between events that are close together
or
ability to detect changes over time
Hemodynamic techniques
Positron emission tomography (PET)
Functional magnetic resonance imaging (fMRI)
- excellent spatial resolution
- poor temporal resolution
Electro-magnetic techniques
Electroencephalography (EEG)
MRI
Magneto-encephalography (MEG)
- poor spatial resolution
- excellent temporal resolution
what is the action potential
rapid change in voltage across a cell membrane, caused by a shift of the ions inside and outside of the cell
how can we analyse EEG data
Time domain
Frequency domain
What are event related potentials (ERPs)
fluctuation of the brain’s electrical field generated by neural activity, induced by stimulus
Brain shows reliable waveform after a stimulus
these waveforms differ based on the cognitive function
can determine how early functions start
EEG artefacts
EEGs are affected by artefacts:
- physiological (e.g., eye blinks, movements, muscle, movement, sweat, cariogenic)
- extraphysiological (e.g, 50Hz UK mains is ambient electrical supply
What is Magnetoencephalography
similar to EEG but records magnetic fluctuations around the head
the electrical currents associated with brain activity create magnetic currents
What is MRI
When placed in strong magnetic field, hydrogen atoms respond to magnetic pulses in a way that depends on the type of tissue they are in, creating differences on the image
what is fMRI
blood oxygen level dependent (BOLD)
- as brain area is active, cells in that area use more resources
- in response, blood oxygenation changes locally
- signal is very slow (low temporal resolution)
what is a raster plot?
a visualisation technique of neural activity
In what way is MEG better than EEG?
MEG signals only minimally distort magnetic fields as they pass through the brain, skull, and scalp.
Therefore, it is much easier to localise the source of a MEG signal compared to an EEG signal
In what way is the EEG better than MEG
MEG is more expensive because the magnetic fields generated by the brain are very weak
What is ECoG?
measures electrical activity in the brain, where the electrodes sit directly on the brain
How does PET work?
- tracer isotope (in the form of water) injected into participants bloodstream while engaging in a cognitive task
- oxygen nuclei rapidly decay, emitting positrons
- collision of positron with electron creates two photons (gamma rays)
- the PET scan determines where this collision took place
what is the BOLD effect, referring to fMRI?
- Blood oxygen level dependent effect
- fMRI detectors measure the ratio of oxygenated to deoxygenated haemoglobin
- this value is the BOLD effect
what is the difference between block design and event related design
Block design = researcher integrates the recorded neural activity over a “block” of time during which the participant performs multiple trials of the same type
ERD = BOLD response links to specific events
what is multivoxel pattern analysis (MVPA)
pattern clarification algorithm in which researcher identifies patterns of neural activity that are consistently present for an event/stimulus etc
what is MRS? (magnetic resonance spectroscopy)
uses MRI machine to obtain chemical compositions of tissues, rather than anatomical information
what is a connectivity map/connectome and what do they do?
visualisation of connections within the brain
capture correlated patterns of activity between different brain regions
what are the 4 steps of constructing a brain network?
1) define network nodes
2) measure correlation between all possible pairs of nodes
3) generate association matrix
4) visualise correlations in connectivity map
