Week 3 - Research Methods Flashcards
What are methods used to study the mind only?
Behavioral methods
What are methods used to study the mind and brain?
Causal methods and correlational methods
Define the causal methods and give examples
“Poking” the brain by interrupting or modifying brain function to observe effects. Examples: Lesion studies (Neuropsychology), Transcranial Magnetic Stimulation (TMS)
Define the correlational methods and give examples
“Listening” to the brain by measuring
brain activity while observing behavior. Examples: fMRI, EEG, Single-unit recordings
modify aspects of the task to assess their impact on performance (e.g., number of distractors in a visual search task).
Independent variables
such as reaction time (RT) and accuracy, measures cognitive processing
Dependent variables
How to design a cognitive experiment?
Give participants a controlled task, such as judging whether two stimuli are
the same or different. Has independent and dependent variables.
How do cognitive experiments help reveal?
Representations: How is information stored in the mind and brain?
Processes: How does the brain manipulate and transform this information?
What are ways to represent information?
Visual representation, verbal representation, conceptual representation
Cognitive experiments systematically manipulate variables to do what?
examine mental representations and study information processing scientifically rather than relying on intuition.
Understanding how the mind and brain organize and interpret the world depends on what?
rigorous experimental design that isolates specific cognitive processes
What is the task of the Posner Letter Matching experiment?
Participants determine whether two
letters belong to the same category.
What is the independent variable in the Posner Letter Matching experiment?
Type of letter relationship (physical match vs. categorical match).
What is the dependent variable in the Posner Letter Matching experiment?
reaction time (RT)
What is the effect of the Posner Letter Matching experiment?
Longer RT for accessing more
abstracted representations (non-physical).
What does the Posner Letter Matching experiment require?
Recognizing letters across
transformations within a category
What is the main idea of the Posner Letter Matching experiment?
Response latencies reflect increasing processing demands
What is the task of the Stroop Task?
Name the color of the printed word, ignoring its meaning
What is the independent variable of the Stroop task?
Relationship between word meaning and ink color.
What is the dependent variable in the Stroop task?
Reaction time
What is the effect of the Stroop task?
Slower to name colors for mis–
matched color-word pairs.
What is the main idea of the Stroop task?
Task-irrelevant information
interferes with processing, demonstrating
cognitive control limitations.
What does the Stroop Task require?
Ignoring the semantic meaning of
word.
- Step-by-step, sequential approach
- Slower, but systematic
- Recognizes processing bottlenecks
Serial Processing
- Multiple processes occur simultaneously
- Faster, but requires efficient resource allocation
- Key for complex, high-speed cognitive tasks
parallel processing
What is the task of the Memory Search Task?
Participants see 1–4 letters
(memory set), then a single probe letter
and must determine if it was in the set.
What is the independent measure of the Memory Search Task?
Number of items in memory set (memory load)
What is the dependent measure of the Memory Search Task?
reaction time (RT)
What does the Memory Search Task require?
Comparing sensory input (probe letter) with stored active memory.
What is the effect of the Memory Search Task?
RT increases linearly with # of items in the set; “yes” and “no” RTs do not differ.
What is the main idea of the Memory Search Task?
The comparison process
operates serially, not in parallel.
What manipulation would you use to determine whether Stroop interference arises from reading?
maybe using someone with poor vision, display other words, look at different populations (testing someone before they learn to read, and someone who knows how to read)
Is the Stroop effect driven only by interference (incongruency)?
How would you test?
look for congruencies as you remove the semantic content
Stages of processing in Memory search
- Encoding – Identify the visible probe letter.
- Comparing – Match sensory
representation with stored active memory. - Deciding – Determine if the probe is a
match or non-match. - Responding – Execute motor action to
indicate the choice.
TRUE OR FALSE: The difference between serial and parallel processing is the comparative phase.
TRUE
What is the task of the Word Superiority Effect?
Participants briefly see a stimulus and identify which of two target letters was present.
What is the independent measure of the Word Superiority Effect?
Type of letter string (word
vs. nonword).
What is the dependent measure of the Word Superiority Effect?
accuracy in recognizing the
target letter.
What does the Word Superiority Effect require?
Comparing sensory input with stored
representations.
What is the effect of the Word Superiority Effect?
Highest accuracy when the target letter is
embedded in a word.
What is the main idea of the Word Superiority Effect?
Context affects perception—individual
letters and whole words are processed in parallel.
What are two ways to manipulate cognitive processes?
- Parametric Manipulation
- Cognitive Subtraction
Vary the amount of a given process
Parametric Manipulation
What is the task of the Shephard Mental Rotation?
Participants determine whether two
images are a match.
What is the independent measure of the Shephard Mental Rotation?
Degree of rotation between the images
What is the dependent measure of the Shephard Mental Rotation?
Reaction time (RT) to make a
decision.
What is required for the Shephard Mental Rotation?
Mentally rotating images to assess
similarity
What is the effect of the Shephard Mental Rotation?
RT increases linearly with rotation angle
What is the main idea of the Shephard Mental Rotation?
Mental transformations take time,
suggesting a continuous process
Add or remove a process from the
processing stream
Cognitive Subtraction
What is the task of the Donders’ Method?
Hit a button in response to a light
turning on across various conditions.
T1. Simple Reaction Task: Press a button as soon as a light appears.
T2. Go/No-Go Task: Press a button only if the light is a specific color.
T3. Choice Reaction Task: Press one button for one color and a
different button for another color
What is the independent measure of the Donders’ Method?
Condition specificity of light detection and response.
What is the dependent measure of the Donders’ Method?
Reaction time
What does the Donders’ method require?
Different amounts of processing steps.
What is the effect of the Donders’ experiment?
RT increases with the number of
processes executed.
What is the main idea of the Donders’ experiment?
Processes are additive.
In the Donders’ method, what happens when you do T2-T1?
time to make discrimination
between light color
In the Donders’ method, what happens when you do T3-T2?
Time to make a motor decision
What are the limitations of subtraction methods?
- lack of process isolation
- serial vs parallel processing
- difficulty identifying mental processes
- oversimplification
- task design challenges
Assumes each component can be measured independently,
but processes often interact
Lack of Process Isolation
Assumes serial processing, which may not apply to tasks
involving parallel cognitive operations
serial vs. Parallel Processing
Multiple processes may contribute to a single
RT difference, making it hard to pinpoint exact cognitive mechanisms.
Difficulty Identifying Mental Processes
Subtraction methods may fail to capture the full complexity of real-
world cognition.
Oversimplification
Creating tasks that isolate processes without contamination is
difficult and requires careful experimental control.
Task Design Challenges
What are the strengths of cognitive/behavioral experiments?
- Identifies mental processes and their operations.
- Cost-effective and easy to implement
What are the weaknesses of cognitive/behavioral experiments?
Does not reveal how mental processes are implemented in the brain
The observed
relationship may be due to chance,
particularly in small samples.
Random coincidence
The assumed causal
direction may be incorrect (e.g., brain
activity could be a response rather than the
cause of behavior).
reverse causality
third factor may
independently influence both observed
variables, creating a misleading association.
confounding variable
single or repetitive transcranial magnetic stimulation
TMS
transcranial focused ultrasound
tFUS
transcranial direct current stimulation
tDCS
transcranial random noise stimulation
tRNS
transcranial altering current stimulation
tACS
Deep brain stimulation
DBS
Damage or removal of specific brain areas to examine behavioral effects
Lesions
Techniques like CRISPR or gene knockouts to alter gene
expression and observe changes in function
Genetic Manipulations
Implanted electrodes deliver electrical impulses to
targeted brain regions, modulating activity.
DBS
Uses light to precisely control genetically modified neurons, enabling
high-precision neural activation or inhibition
Optogenetics
Uses magnetic fields to non-invasively
stimulate or inhibit specific brain regions.
TMS
What are the study of lesions used for?
Studying the effects of brain damage on behavior and
cognition to infer structure-function relationships.
Pros to studying lesions
Provides strong causal evidence linking brain regions to specific
functions.
* Can reveal long-term functional consequences of brain damage.
* Natural lesions (e.g., stroke, trauma) offer insight into brain
disorders from real-world clinical cases.
Cons to studying lesions
Lack of experimental control over lesion location and extent in natural cases.
* Brain plasticity can compensate for damage, complicating
interpretation.
* Ethical and practical limitations prevent intentional lesion studies in humans.
What causes brain damage?
- stokes
- Traumatic Brain injuries
- Viral infections
- Tumors
- Neurodegenerative disorders
Disrupt blood flow, causing predictable damage based on vascular anatomy.
strokes
Result from impacts, leading to structural damage
and cognitive impairments.
Traumatic Brain Injuries
Cause brain inflammation
and neuronal damage (e.g., Herpes Simplex Encephalitis)
Viral infections
Abnormal growths disrupt nearby brain regions and functions.
Tumors
(e.g., Alzheimer’s, Parkinson’s, Huntington’s): Gradual neuron loss leads to cognitive and motor deficits.
Neurodegenerative disorders
Explain the case of Tan.
He had a stroke: Loss of speech, linking left frontal lobe to language.
Explain the case of Phineas Gage
Had a TBI; Frontal lobe damage led to
personality and impulse control changes.
Explain the case of Henry Molaison
Neurosurgery:
Hippocampal removal caused profound memory
deficits.
Explain the case of split brain patients
Neurosurgery: Cutting the
corpus callosum revealed hemispheric specialization.
Explain the groups being tested with the Stoop task
TBI patients vs. healthy controls (HC)
Result/findings of Stroop task
Results: TBI patients showed slower RTs and
more errors, especially on incongruent trials.
* Main Point: TBI impairs inhibitory control,
reflecting cognitive regulation deficits.
One patient group is
impaired on Task A but performs normally on
Task B
Single dissociation
Patient Group 1:
Impaired on Task A, normal on Task B. Patient
Group 2: Impaired on Task B, normal on Task A
Double Dissociation
What is the key takeaway of doing single vs. double dissociation studies?
Key Takeaway: Double dissociations provide
stronger evidence for selective impairments,
supporting the idea that different cognitive
processes rely on distinct neural mechanisms.
Limitations to single dissociation studies
they can only demonstrate that one cognitive function is impaired while another is relatively spared, but this does not definitively prove that these functions are separate and localized in different brain regions
What does lesion effects/damage to the MD result in?
Lesion Effects: Damage to MD
impairs memory and emotional processing, underscoring its cognitive role.
Tracer studies in primates show MD links to?
executive function circuits in the frontal cortex
What are genetic manipulations used for?
Modifying gene expression (e.g., CRISPR, knockouts) to
study the genetic basis of neural function and disease.
Pros of genetic manipulations
- Allows precise control over specific genes linked to brain function or dysfunction.
- Useful for modeling neurological disorders at the molecular level.
- Can reveal long-term effects of genetic changes on neural circuits and behavior.
Cons of genetic
- Effects can be widespread, making it difficult to isolate specific
neural functions. - Limited to animal models; human applications are ethically
complex. - Developmental compensations may obscure direct gene-function
relationships
Orbital frontal cortex function
emotion, reward, and decision-making
Lateral frontal cortex function
executive control, reasoning, planning, and working memory
What is DBS used for?
Modulating brain activity in neurological disorders like Parkinson’s disease, depression, and epilepsy
Pros to DBS
- Provides real-time, adjustable modulation of brain
function. - Offers therapeutic benefits for movement disorders and
psychiatric conditions. - Allows for precise targeting of deep brain structures
Cons to DBS
- Requires invasive surgery, carrying risks like infection
and hardware complications. - Mechanisms of action are not fully understood.
- Effects can be inconsistent across individuals.
What is optogenetics used for?
Controlling neuron activity with light in genetically
modified animals to study brain circuits.
Pros to optogenetics
- High spatial and temporal precision in manipulating
specific neurons. - Allows testing of neural circuit function.
- Can selectively activate or inhibit targeted cell populations
Cons to optogenetics
- Limited to animal models; human applications are
ethically complex. - Invasive procedures are needed to deliver light
stimulation. - Difficult to apply broadly across complex neural
networks.
What is TMS used for?
Non-invasively stimulating or inhibiting brain regions to study neural function and treat conditions like depression
Pros to TMS
Safe, reversible, and non-invasive. Provides causal evidence of brain function in humans by disrupting activity. Can be used repeatedly without long-term harm
Cons to TMS
Limited spatial resolution- cannot precisely target deep brain structures. Effects are temporary and can be variable. Mechanisms of action remain unclear for some applications.
Involves recording electrical activity from individual neurons (single-unit) or groups of neurons (multi-unit) in animals to understand neural behavior at a highly detailed level.
Electrophysiology
Captures electrical activity directly from the surface of the brain using electrodes
placed on the cortex, offering high spatial and temporal resolution of brain activity.
ECog (Electrocorticography)
measures electrical activity through the scalp, while ERP refers to brain responses tied to specific sensory, cognitive, or motor events, providing insights into brain function and timing.
EEG / ERP (Electroencephalography / Event-Related Potentials)
Detects magnetic fields produced by neuronal electrical activity, allowing for
the non-invasive study of brain function with good spatial and excellent temporal resolution
MEG (Magnetoencephalography)
Uses X-rays to create detailed images of the brain, useful for diagnosing injuries,
tumors, and other structural abnormalities
CT (Computed Tomography)
Visualizes metabolic processes in the brain by detecting radioactive tracers, useful for studying brain function and disorders.
PET (Positron Emission Tomography)
Provides high-resolution images of the brain’s structure and anatomy using
magnetic fields and radio waves, without exposure to ionizing radiation.
MRI (Magnetic Resonance Imaging)
A type of MRI that maps the diffusion of water molecules in brain tissue,
revealing the microstructural organization of white matter pathways.
DTI (Diffusion Tensor Imaging)
Measures brain activity by detecting changes in blood flow, offering insights into the brain’s functional areas during tasks or rest.
fMRI (Functional Magnetic Resonance Imaging)
Pros to Electrophysiology
Offers precise, real-time measurement of spiking activity with high resolution.
Cons to Electrophysiology
Invasive, limited human use, and may not fully capture broader neural circuits.
- reflects summed, synchronous dendritic activity (input) from a population of neurons.
- captures coordinated activity and network dynamics, while spikes convey detailed
neuronal communication
LFPs (local field potential)
In Electrophysiology, what does the spiking activity represent?
Precise, all-or-nothing electrical signals
What is ECog (Electrocorticography) used for?
Identifying epileptic
zones and mapping brain
functions during surgery
Pros to ECog (Electrocorticography)
Provides high spatial
and temporal resolution,
making it ideal for precise
functional mapping.
Cons to ECog (Electrocorticography
Highly invasive,
requiring surgical exposure of
the brain, so it is mainly used
in clinical settings.
What is Electroencephalography (EEG) used for?
Diagnosing epilepsy, sleep
disorders, and studying brain responses to cognitive and sensory tasks.
Pros to Electroencephalography (EEG)
Non-invasive, affordable, and offers
excellent temporal resolution for
tracking rapid neural activity
Cons to Electroencephalography (EEG)
Limited spatial resolution and
vulnerable to artifacts from muscle movement, eye blinks, and external noise
EEG signal changes that occur in response to specific events, such as sensory stimuli or cognitive processes.
Event-Related Potentials (ERPs)
Consistently appear at specific time points following an event, allowing researchers to link brain activity to cognitive functions
Time-locked Measurements
Due to their small magnitude, ERPs are extracted by averaging EEG data across trials, removing background noise and isolating the event driven response.
Trial Averaging
Distinct waveform features reflecting different cognitive functions.
ERP Components
The timing of ERP components reveals processing stages.
Latency
What are the cognitive insights of ERP?
ERPs help dissect sensory, attentional, and decision-related processes
What is an MRI used for?
MRI provides high-resolution
brain images to study structure-function
relationships, detect abnormalities, and
map cognitive processes.
Pros to MRI
Non-invasive, no radiation, and
excellent spatial resolution for detailed brain mapping.
Cons to MRI
Expensive, time-consuming, and requires subjects to remain still in a confined space.
Structural MRI modalities
- cortical thickness and area subcortical volume
- Diffusion tensor imaging
Functional MRI modalities
- Task fMRI
- Resting state fMRI
What is Diffusion tensor imaging used for?
Maps and characterizes white
matter tracts, helping to understand brain
connectivity, cognitive functions, and
neurological disorders.
Pros of Diffusion tensor imaging
Offers unique insights into white matter pathways beyond standard MRI, aiding in the diagnosis of conditions like multiple sclerosis, stroke, and TBI.
Cons of Diffusion tensor imaging
Susceptible to motion artifacts; assumes uniform water diffusion, which may not always reflect the brain’s complex microstructure.
What are fMRIs used for?
Studies brain activity linked to cognitive processes by measuring blood flow changes, identifying brain regions involved in tasks like decision-making and perception.
Pros of fMRI
Non-invasive, high spatial resolution, and safe for repeated use due to lack of ionizing radiation.
Cons to fMRI
Limited temporal resolution
compared to EEG; indirect measurement via BOLD response may not fully capture neural activity; requires stillness during scanning
measured by functional magnetic resonance imaging (fMRI). It’s a homeostatic process that increases blood flow to active areas of the brain to deliver more oxygen and nutrients
Hemodynamic response function
More deoxygenated hemoglobin leads to
Lower MR signal
More oxygenated hemoglobin leads to
Higher MR signal
a signal detected in functional magnetic resonance imaging (fMRI) that reflects changes in brain blood flow and oxygenation
blood oxygen level-dependent (BOLD) response
What are computational modeling used for?
Simulating brain functions to test theories, predict neural outcomes, and integrate experimental data.
pros of computational modeling
Allows hypothesis testing beyond experimental limits, linking diverse data to explore cognitive mechanisms.
cons of computational modeling
Relies on data quality and assumptions, risking oversimplification; complex models can be hard to validate.
P100
selective attention, has a latency of 100 ms
N100
selective attention, has a latency of 170-200 ms
N200
Mismatch negativity, recognition, categorization, has a latency of 225-250 ms
P300
Working memory, Cognitive load, has a latency of 300 ms
