PSYCH 1200 –CHAPTER 2
- Curiosity, skepticism, and open mindedness are key scientific attitudes. The scientific
process precedes through several steps:
1. Asking questions based on some type of observation;
2. Formulating a tentative explanation and a testable hypothesis
3. Conducting research to test the hypothesis
4. Analyzing the data and drawing a tentative conclusion
5. Building a theory
6. Using the theory to generate new hypotheses, which are tested by more research.
- In everyday life we typically use hindsight (after-the-fact understanding) to explain
behaviour. This approach is flawed because there may be countless possible
explanations and no way to ascertain which is correct. Psychologists prefer to test their
understanding through prediction, control and building theories about the causes of
- A good theory organizes known facts, gives rise to additional hypotheses that are
testable, is supported by the findings of new research and is parsimonious.
- An operational definition defines a concept or variable in terms of the specific
procedures used to produce or measure it.
- Psychologists assess behaviour by obtaining participants’ self reports, gathering reports
from others who know the participants, directly observing behaviour, and measuring
- The goal of descriptive research is to identify how organisms behave, particularly in
natural settings. Case studies involve the detailed study of a person, group or event.
Case studies often suggest important ideas for further research but they are a poor
method for establishing cause-effect relations.
- Naturalistic observation gathers information about behaviour in real-life settings. It
often yields rich descriptions of behaviour and allows the examination of relations
between variables. Researchers must be careful to avoid influencing the participants
being observed and to interpret their observations objectively.
- Surveys involve administering questionnaires or interviews to many people. Most
surveys study a subset of people (a sample) that is randomly drawn from the large
population of people the researcher is interested in. A major advantage to surveys is
that representative samples allow for reasonably accurate estimates of the opinions or
behaviours of the entire population. Unrepresentative samples, however, can lead to
inaccurate estimates. Survey results can be distorted by interviewer bias or biases in the
way participants report about themselves. - Correlational research measures the association between naturally occurring variables.
A positive correlation means that higher scores on one variable are associated with
higher scores on a second variable. A negative correlation occurs when higher scores on
one variable are associated with lower scores on a second variable.
- Causal conclusions cannot be drawn from correlational data. Variable X may cause Y, Y
may cause X or some third variable (Z) may be the true cause of both X and Y.
Nevertheless, if two variables are correlated, then knowing the scores of one variable
will help predict the scores of the other.
- A well-designed experiment is the best way to examine cause-effect relations.
Experiments have three essential characteristics;
1. One or more variables are manipulated.
2. Their effects on other variables are measured
3. Extraneous factors are eliminated or reduced so that cause-effect conclusions can be
- Each variable manipulated by the experimenter is an independent variable. Variables hat
are measured are dependant variables. The independent variable is viewed as the cause,
the dependent variable as the effect. The experimental group receives a treatment or an
active level of the independent variable, whereas the control group does not. The behaviour
of the control group sets a standard against which the behaviour of the experimental group can
- In some experiments different participants are randomly assigned to each condition, creating
experimental and control groups that are equivalent at the beginning of the study. In other
experiments participants are exposed to all the conditions, but the order in which the conditions are
presented is counterbalanced.
- Researchers often examine several casual factors within a single experiment by
simultaneously manipulating two or more independent variables. They examine the
separate influence of each variable on behaviour and determine whether particular
combinations of variables produce distinct effects.
- An experiment has high internal validity when it is designed well and permits clear casual
conclusions. Confounding occurs when the independent variable becomes mixed with an
uncontrolled variable. This ruins internal validity because we can no longer tell which
variable caused the changes in the dependent variable.
- Internal validity is weakened by;
1. Demand characteristics which are cues that tip off the participants as to how they
2. Placebo effects in which mere expectations of receiving a treatment produces a change
in behaviour. 3. Experimenter expectancy effects which are the subtle ways a researcher’s behaviour
influences participants to behave in a manner consistent with the hypothesis being
- The double-blind procedure prevents placebo effects and experimenter expectancy effects
from biasing research effects.
- External validity is the degree to which the findings of a study can be generated to other
people, settings and conditions. By replicating (repeating) a study under both similar and
dissimilar circumstances, researchers can examine its external validity.
- Psychological research follows extensive ethical guidelines