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Research Methods
Experiments and Variables
Experiments
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Studies
Research Methods > Experiments and Variables > Experiments
5 cards
Cards (11)
Experiments
Laboratory:
Controlled
No extraneous variables, high internal valid
Participants aware; DC
Replicable
Lack eco valid due to artificial setting + low mundane realism
Field:
Natural
Participants unaware
High eco valid
Representative
Low extraneous variable control (difficult to stop confounding variables)
Natural:
IV + DV occur naturally
No manipulation required
Double-blind:
Participants + researcher unaware
Controls for DC + experimenter effects
Enables objective, bias-free interpretation
Single-blind:
Participants unaware
Reduces DC
Observations
Watch and record behaviour in categories
Natural IV
Quantitative
and
qualitative
(written descriptions)
Many research methods use it
Event
(count occurrence over period) or
time sampling
(at regular intervals)
Overt
:
Aware
Ethic (consent)
Demand characteristics
Social desirability
Covert
:
Unaware
Genuine
Unethical
Participant:
In group
Detail
Non-participant
:
Not in group
Accurate
Structured
:
Control
Standardised
Test-retest reliable
Low eco valid (artificial)
Naturalistic
:
Natural
Eco valid
Unreliable
Low internal valid
Studies
Longitudinal
Large cohorts, high representative
No
individual differences
Several
test points
over period, get same data
Recruit cohort + take immediate data;
baseline
Often last weeks or months, some last years or
decades
Investigate
CoT
Collects
data from same cohort repeatedly over
extended period
High
drop-off rate
, intrusive; due to amount of data collection
Early data outdated/irrelevant
Cross-Sectional
Cross-section of participants studied at once
Assumption younger group turn into older group
Cheaper +
time-efficient
Valid, up to date
Cannot establish cause
Time-locked + ungeneralisable to other groups
Cross-Cultural
Data from different cultures
Clinical Psychology
:
Diagnosis
Treatment effectiveness
Attitude
Uni prevalence
: Nature, diff: Nurture
Stop
ethnocentrism
, raise
generalisability
Same procedure not all, invalid (culture stigma)
Subjective due to researcher norms
Meta-analysis
Secondary data
Different cultures/times
Large data amounts
Used when firm conclusions cannot be drawn w/out comparison or if there is conflicting/inconsistent data
Overall analysis usually reported in terms of
effect sizes
Strengths:
Cost/time-effective
No ethical issues
Analyse data that already exists
Weaknesses:
Researcher has no involvement
Uncertain on reliability or validity
Publication bias
Content Analysis
Analyses artefacts rather than
participants
When info is too costly,
impractical
or impossible
Useful in conjunction w/ other methods
Manifest
Content: “On surface” e.g. frequency words used
Latent
content: In-depth “beneath surface” e.g. used positively or negatively
Quantitative Data: Start with
qualitative
, content analysis
Researcher identifies
“categories”
or “coding units” (inductive or deductive), e.g. theme
Strengths:
Turns qualitative to
quantitative
, so inferential tests can be used to determine
statistical
significance
Easily applicable;
inexpensive
, non-invasive
Weaknesses:
Category selection + recognition is
subjective
Transforming qualitative to quantitative data, you lose detail;
reductionist
Brain Scanning
CAT
Giant X-ray
Interpreted by computer
May use dye for highlighting
PET
Inject glucose w/ radioactive trace; decay + emit gamma rays
More active/glucose; red/orange = high, blue/green = low
Most invasive
fMRI
Measure O_2
Detects haemoglobin magnetism
Oxygenated (
diamagnetic
)
Deoxygenated (
paramagnetic
)
Bigger change = more intense colour; activation map
Strengths
Painless
Well-controlled + Objective
fMRI allows detailed images with no
radiation
, unlike CAT + PET
Weaknesses
Limits participant activity; must lie still, small movement can distort imaging
PET/CAT use radioactivity, exposure has to be limited
fMRI
expensive
+ not useful for all (metal in bodies)
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