Modules 2 and 3 - Research Methods


That’s Not True!!!!

Research Methods in Psychology

• Cause and effect

– With an experiment, we can determine cause and effect because we are systematically manipulating variables

– Hypothesis-what do we think will happen in the study?

– Independent variable(s):

– Dependent variable(s):

• Operational definitions-

– What do you mean by the I.V.?

– What do you mean by the D.V.?

– You need to define them so people who read your study know what you are talking about

• Subjects:

– Population

– Sample - #s

– Random Assignment

– Experimental Group

– Control Group

• Extraneous vs. Confounding variables

– Extraneous –

– Confounding –

Flaws to look for

• 1. Internal

– The problem with internal validity is that it becomes very difficult to generalize the results to the rest of the population. (This can also be a problem with case studies).

• 2. External validity-

• 3. Sampling bias -

• You need to draw a large enough sample to represent the population under study and then utilize random sampling

• 4. Placebo effects –

• Simply placing something in one’s mouth may cause one to experience a placebo effect

• Placebo effects can ruin the experiment because you cannot tell if the drug actually had an effect on the subject or not.

• 5. Distortion of self-report-Occurs when interview and surveys are given. The subject may lie in giving their answers (or just stretch the truth). Can happen in one of two ways:

• A. Social desirability-

• B. Response set-

(Ex- when people agree with or disagree with everything on the survey. Most surveys are set up to elicit positive/negative answers or so that different choices should be made.

• 6. Experimenter bias -

• The best way to overcome this is to do a double-blind study, in which the experimenter does not know which subjects are in which groups

Developmental Studies

• In order to study development of human beings, we use several different designs:

– 1. Cross-sectional

– 2. Longitudinal

– 3. Sequential

Pros and cons with Research


• 1. Naturalistic Observation

– Pros –

– Cons –

• 2. Laboratory Experiment

– Pros –

– Cons –

• 3. Surveys

– Pros –

– Cons –

• 4. Interviews

– Pros –

– Cons –

• 5. Case Study

– Pros –

– Cons –

Ethical Issues in Psychology

• 1. Subject participation – voluntary

– Should not be forced or feel pressured

– Should be informed of any factor of research that might make them decide not to participate

– Should be allowed to end participation at any time and still get paid (if they are getting paid)

• 2. Subjects are not to be harmed in any way

– Protect from psychological and physical harm

– Studies that may only effect one’s emotions in a slight way are acceptable

• 3. Deception of participants – Is it okay?

– Should be done to inform participants

– Debriefing of subject is usually necessary

• 4. Right to privacy should not be violated

– Don’t give out information on your subjects

– If data regarding subjects will be released, subjects must be informed and consent must be obtained

• 5. Can we cause them harm?

– Yes to animals – but you must be able to justify it

– Animals should be maintained in a manner that is considered decent treatment

• 6. Approval must be obtained from the institution that the researcher works for

– Research must be reported in an ethical fashion

– Research should be reported as soon as possible for verification

Measures of Central Tendency

• Mean-Average of all the data

• Mode-# that appears most often. You may have a bimodal distribution which means that two #’s appear the same # of times and are the most frequent #’s in the data set.

• Median-# in the middle

• Range – subtract the lowest # from the highest #

Correlational Studies

• While experiments tell us about cause and effect,

• Usually after the fact

– correlational studies do NOT tell about causation

• Often cannot experiment on humans

– they ONLY tell us if there is a relationship

• Follow-up may be experiment with animals

Correlational Research

• Look for:

– Positive vs. negative relationships

– Strength of the number

• +1 –

Correlational Research

• +.7-.9 –

• +.4-.6 –

• +.1-.3 –

• 0 –