The scientific Method
Scientist use objective procedures
free from bias
if another uses the same procedure with same people we would
expect the same results.
4 Basic Goals…to be more confident in conclusions drawn from observations
what describing happenings
when predicting happenings
why controlling happenings
what 2 explaining happenings
3 Elements of Scientific Method
Theory: explanation/model of how something works and interconnects ideas
use to explain prior observations
make predictions about the future
Hypothesis: specific testable prediction about the outcome supporting theory
Research: careful collection of data object info that provides a test of
When research is replicated we have more confidence
repeating study and getting the same results
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Piaget ▯child development theories led to a number of hypotheses
Freud ▯interpretation of dream generated few testable hypotheses
Good theories should generate wide varieties of testable hypotheses
*Unexpected findings can be valuable
= SERENDIPITY : unexpected discovery of something important.
view summing up
Types of studies in psychology research
observing and noting behavior to analyze it objectively
Keep track of a participant’s, at a point in time, behaviours may take years to unfold.
observer separate from situation and makes no attempt
to change the situation.
researcher involved in situation 1 2
Advantage: valuable in early stages of research when determining if a phenomena exists. Takes place in a
real world setting.
Disadvantage: Errors in observation because of an observer’s bias may occur. Presence of observer can
change behaviour witnessed.
changes that occur over time
seeing future development due to interventions
Advantage: Provides information about effects of age that allow researchers to see developmental changes.
Disadvantage: expensive, long, may lose participants over time.
comparing different groups to make inferences about both at the same time.
Advantage: faster, less expensive
Disadvantage: unidentifiable variables (3 variable problem)
systematic errors in observation that occur because of an observer’s
It can change the behaviour being observed = Experimenter Expectancy Effect
The mice had faster recorded results because the participants were told they
Some aspects of our own behaviour are not under our conscious control.
It is best if the person running the study is blind or unaware of study’s hypotheses.
examine variables related in the world without research attempting to alter
A variable that the researcher did not control
Popular because, they rely on naturally occurring relationships
Possibly required for ethical reasons
1) Cannot be used to support causal relationship
(one thing happened due to another)
2) Directionality cannot show the direction of the cause/effect relationship
between the variables (A▯B ; B▯A)
3) An unidentified variable maybe involved. (Third Variable Problem C
caused A & B )
*Typically researchers use stats to rule out potential problems
Researcher has maximum control over the situation
researcher manipulates one variable to examine that variable’s effect on a
Control group (comparison)
Participant received no intervention or different intervention from
the one being studied.
Experiment group (treatment)
1 Participant that recei2e intervention
A: demonstrate causal relationships, avoids directionality
D: takes place in artificial setting Independent variable: variable manipulated
Dependent variable: variable measured
*Confound: Anything that affects dependent variable and may unintentionally vary between study’s
By eliminating and preventing possible confounds, a researcher can be more confident that
The independent variable caused the change in the dependent variable
Random Assignment is used to establish equivalent groups
The only way to make group’s equivalency more likely is to use random
assignment. Each participant has an equal chance of being assigned to any
level of independent variable.
Individual differences are likely to exist, but these differences are likely to average out
as participants are assigned to either the control or experimental groups randomly
random assignment also balances out known and unknown factors
Population ▯ everyone in the group the experimenter is interested in
Sample ▯subset people who are studied
Random sampling ▯each member of population has an equal chance of
Convenience sampling ▯people available for the study (most often the case in psychological
*A larger sample size will provide a more accurate estimate of a population than a smaller sample
*selection bias: when groups are not equivalent because participants differ between
Metaanalysis ▯analysis on studies that have already been conducted
provides a stronger evidence
has the concept of replication built into it
Data Collection Methods
The data collection method used must be appropriate for questions at the
level of analysis
▯measure brain processes and different hormones using brain
▯individual difference among participants responses using
questioning on indirect assessments
▯observing people within a single culture and how they interact