Lecture 2 Flashcards
Experiments
IV has two or more levels, you manipulate it to see its effect on the DV
Most common
Can infer causality
Low ecology
Natural observation
Watch people in the field
Score their behaviour (or assess in some way)
No causality
Basic assumption for all research
Events are governed by some lawful order
The three goals of research
Measurement and description (How/why)
Understanding and prediction (How/what will happen)
Application (to help people usually)
If you divide people into two groups and have some play video games and some not, then measure spatial memory, you can describe the changes and caveats
Maybe another study could determine what part of the game accounted for the observed change
Could then predict changes in spatial memory caused by playing the game
Could maybe then prescribe game playing to help people improve spatial memory
Structure of a scientific paper
Introduction:
Theories, hypothesis
Methods:
Operational definitions
Acquisition of empirical evidence
Results:
Adherence to the scientific method
Precision
Analysis of empirical evidence
Discussion:
Openness - strengths/weaknesses, unexpected findings (good papers would be honest about this_
Willingness to reject hypothesis and draw correct conclusions (must be willing to say it did not work)
Theories
Organized systems of assumptions that aim to explain phenomena and their interrelationships
Should be referenced in the introduction of papers
Organize findings from prior research into a coherent set of ideas.
Hypotheses
Attempt to predict or account for something. specify relationships among variables and are explicitly tested
Should be explicitly stated in the intro of papers
Two sources of hypotheses
(a) theories
When a hypothesis is derived from a theory, it tests the theory. If the hypothesis is correct this adds supporting data to the theory (but does not prove it). When it is not, the theory must be revised.
(b) Personal experience
If this is for an experiment it is a formal statement that when X is changed this will cause Y to change (both in specific ways) or if there is no causation implied, that X and Y are related predictably.
Operational definitions
define terms in hypotheses by specifying the operations for observing and measuring the process or phenomenon
Relatively subjective: ie you define it
Can be very hard
Goes in method of papers
Random sampling/assignment
Randomly select people from the population
Randomly assign them to a condition
This way the chances of their being systematic differences between the groups are minimized as the differences should occur in both groups and so cancel out
A true random sample is representative of the population
By making the sample representative of the population, you allow the study to infer something about the population. If it is not, you cannot do this (or should not).
Unrepresentative samples may not apply to everyone.
Convenience sampling
Samples that are convenient to get.
Sometimes needed like in rare medical conditions
Often WEIRD which makes findings less generalizable
Skepticism
Do not accept ideas based on faith or authority
Do not assume everything was done correctly, treat every aspect of a study with caution.
Assess
Willingness to reject H1
Confirmation bias
Hard to do
Conformation bias: the tendency to look for or pay attention only to the things that are consistent with your own belief. Big issue with social media, big issue with data interpretation.
Karly Popper’s Critical Rationalism
Falsifiability
A scientific theory must make predictions specific enough to disconfirm the theory. It must predict what will and will not happen.
Often our impressions are wrong.
Example of confirmation bias & the importance of falsifiability: Prefrontal lobotomy
Egaz Moniz Damage PFC Treatment to schiz Drops notable psychotic behaviors Thought of as acceptable, got a Nobel Controlled studies showed useless Does not drop non-psychotic schiz symptoms Drops DIRECTED behavior across board so psychotic directed behaviors (that is disturbing to others) drops but so does non-psychotic directed behavior (like dressing yourself). Replaced with antipsychotics
Moniz hypothesized it would drop psych symptoms, then focused on the behaviors he wanted to see drop (psychotic one’s) and ignored those that did not confirm this belief. He did not define what changes in behavior might be negative.
If he had defined this better (eg said there would be no cognitive impairment), it would have been falsified. 20k were done.
What makes evidence empirical?
Reliability/Validity
What makes evidence empirical?
Evaluate measures based on reliability and validity
A test must be reliable to be valid but a reliable test can be invalid (if the test reliably measures an invalid construct).
Reliability
2 types
How consistent is the measurement?
80% is good
(1) test-retest reliability
Are scores similar from one session to another?
Sometimes one may improve if its the same test again and again.
(2) Alternate-forms reliability
Are scores similar on different forms of tests?
Correlational studies
Descriptive studies looking for relationships between phenomena
Correlation is a statistical measure of how strongly two variables are related to one another (between -1 and1)
Strengths: Can test predictions, evaluate theories and suggest new hypotheses
CANNOT INFER CAUSALITY
Although often reported that way both in the media and in sloppy discussions
Often shown as scatter diagrams
Stronger correlations yield better predictive power
Random selection of ptps from the population
Key for generalizability
Not always possible, aim for it
If not, say so in discussion
Random assignment of ptps
To each group
Experiment/control
Give placebos to account for placebo effect (as everyone thinks they have the drug)
