Psychology as a Science Flashcards
What are the 4 ways of acquiring knowledge?
Authority figures
Introspection
Experience
The scientific method
What is the scientific method?
Generate a hypothesis based on observation/theory
Generate testable predictions
Obtain data
Interpret data and come to conclusions
Relate findings back to the theory/generate more hypotheses
What are the characteristics of the scientific method?
Rational, systematic, critical, objective and open to scrutiny. It must be potentially falsifiable and ideally reproducible.
Define theory
An evidence based conceptual framework that tries to explain a set of facts/observations which can be used to make testable predictions.
What is a hypothesis?
A proposed explanation that comes from a theory.
What is a prediction?
A specific and testable prediction that stems from a hypothesis
Define operationalise
Defining variables in an objectively measurable way
What is a likert scale?
Strongly agree to strongly disagree in response to a statement
What is a visual analogue scale?
Pps asked to place a mark along a line with 0/agree on one end and 10/disagree in the other.
What are cohort effects?
Pre-existing differences in addition to the difference in independent variable.
What is a correlational analysis?
Assessing the strength and direction of a relationship between two co-variables.
What are Hume’s characteristics of cause and effect?
To say A causes B imples that
Change in A are ASSOCIATED with change in B
Change in A reliably PRECEDES change in B
without change in A, change in B does not occur (but only true if A is the SOLE cause of B)
What is J.S. Mill’s method of difference?
Observing the effects produced by 2 situations that are identical except in one respect, if the phenomenon occurs in one situation but not the other, then the difference between the two conditions is the cause. This is now known as the experimental method.
What is a null hypothesis?
Difference between groups occurred by chance
What is an alternative hypothesis?
The difference is so large that it is unlikely to have occurred by chance
What is a type 1 error?
When the null hypothesis is rejected even though it is true.
What is a type 2 error?
Accepting the null hypothesis when it is false
What is null hypothesis significance testing?
A way in which results can be assessed in an objective way, by assuming the null hypothesis is true, unless there is enough evidence to make it more likely that the alternative hypothesis is true instead.
What are the disadvantages of null hypothesis significance testing?
Encourages p-hacking where data is selectively fished for ‘significant’ results that were not hypothesised.
Dichotomous thinking in which p.05 is no result.
“File drawer problem” - non-significant findings are hard to publish.
What is nominal data?
Categorical or frequency data
What is ordinal data?
Data that is ranked
What is interval data?
Scale with equal intervals between points with no true zero point.
What is ratio data?
Scale with equal intervals between points with a true zero point
What is reliability?
Something is reliable when it is Consistent and reproducible
How is reliability measured? (4)
Test-retest
Alternate forms
Split-half method
Inter-rater
What is validity?
Something is valid if it measures what it claims to be measuring.
How is validity measured?
Face validity (intuitively looks valid) Content validity (test covers material which is relevant) Criterion validity (predictive or concurrent- does performance correlate with later or other tests of current performance) Construct validity (correlate with known measures of phenomena) Ecological validity (relevance to the real world)
What factors affect validity?
The method of difference, if experimental design is not used kr is used poorly findings will have limited validity
Norms, sub group norms may differ
Standardisation - reliability is needed in order for it to be valid.
What factors effect reliabilty?
Traits vs states Precision of measurement Sample size Time between tests Format of tests Variability between individuals
What are the threats to internal validity of an experiment?
Time threats
Group threats
Participant reactivity threats
What are time threats?
History (extraneous events occurring before post test)
Maturation (pps change during the course of the study)
Selection-maturation interaction (different groups mature at different rates)
Repeat testing
Instrument change (ie experimenter becomes practiced or bored)
How can time threats be overcome?
Add control groups, ensure groups only differ on one IV, avoid repeat testing, random allocation of pps, highly standardised procedures.
What are group threats?
Non-equivalence of groups (cohort effects)
Regression to the mean (pps that score extreme on one occassion tend to give less extreme scores when tested again)
Individual differences in personality
Control group aware of its status.
How are group threats overcome?
Ensure pps only differ on one variable.
What are participant reactivity threats?
Hawthorne effect
Experimenter effects
Placebo effects
How are participant reactivity threats overcome?
Double blind procedures
