Lecture 2 notes
Lecture 2: Research methods in Psychology
1. Psychology: Scientific approach to behavior
2. Research methods in Psychology: Experimental and non-experimental approaches
3. Ethical issues in psychological research
1) Psychology: Scientific approach to behavior
Whether the objects of study are gravitational forces or human behaviors under stress,
scientific approach assume that events are governed by some lawful orders. Psychologists
assume behaviors were governed by discernible laws or principles. The tasks of psychologists
are to uncover and verify these laws and principles of behaviors like what Newton has done in
physics.
1.1) Goals of scientific studies
Three interrelated goals:
a) Measure and describe:
The first goal of psychology is to development measurement techniques/methods to enable
researcher to describe target behaviors clearly, precisely and objectively. Before we can try to
explain or predict any behaviors, we have to be able to define and describe it objectively.
b) Understand and predict:
A higher-level goal of psychology is understanding and predicting. We try to understand
certain behaviors (e.g. communicative behaviors) by explaining the reasons for its occurrence
(e.g. needs to be understood). In the process of understanding human behaviors, psychologist
propose different hypothesis (a tentative and testable statement about the relationship between
two or more variables. Variables are any measurable conditions, events, characteristics, or
behaviors that are controlled or observed in a study) to test and evaluate their thoughts about
patterns of human behavior (e.g. men are less sociable than women or men tends to share
emotional events with women).
After certain hypothesis were tested, psychologists may propose a theory (“is a system of
interrelated ideas used to explain a ser of observations.” p.38) to predict behaviors.
refer to Figure 2.1 Theory construction
c) Apply and control
Once researchers understand a psychological phenomenon, they try to apply the research
findings to practical problems in different settings (e.g. training, school or business). Their aims
to apply the psychological knowledge they have are in general to promote well-being of human
and effectiveness of their behaviors.
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Q: Can you make up a hypothesis?
1.2) Steps in a scientific study
The Five Steps of the Scientific Method
1. Formulating hypothesis
Hypothesis – A testable statement which describes the
relationship between two variables.
It predicts a research outcome that could be either verified or
falsified.
A research outcome which is consistent with the prediction
supports the hypothesis.
2. Designing a research
Measurement – Designing valid & reliable ways of measuring
variables under study
Manipulation and control – Manipulate variables under study &
control the effects of unrelated variables
Data collection procedures – Design procedures that minimize
biases & errors
3. Gathering data
Data – Information gathered by researcher in order to test
hypothesis
Types of data – Can be quantitative or qualitative
refer to Table 2.1 Key
Data collection
techniques in Psychology
4. Analyzing the results
5. Publishing, criticizing, and
replicating the results
Statistical analyses – to describe numerical data in an
interpretable way and to deal with sampling error
Qualitative analysis – to organize and categorize data
Research findings need to be replicated to be regarded as
sufficiently verified
Failure to replicate research findings may suggest
methodological flaw
refer to Figure 2.2 Flowchart of steps in a scientific investigation
1.3) Advantages of scientific approach
Findings are clear and precise
Findings are more reliable; can be verified and replicable
Any limitations of scientific approach?
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2) Research methods: Experimental and non-experimental approaches
Population and sample
• Population: Entire set of individuals to which generalizations will be made based on an
experimental sample
• Sample: Subset of a population selected as participants in an experiment
Variables
• Independent variable: Variables that are free to vary independently of any other variable in
the situation
• Dependent variable: Variables that are the result of changes in one or more independent
variables
• Confounding variable: Variables that are not under concern of the study
Types of Psychological Research
• Experimental approach: Experiments
• Non-experimental/Descriptive approach:
Correlational studies; Survey; Naturalistic observations; Case studies
Experiments
• Contains an experimental group and a control group
• The experimental group is treated in the same way as the control group except the
systematic manipulation of the independent variables, whereas the dependent
variables are compared between groups
• Confounding variables are held constant for all conditions
Correlational Study
• Correlational analysis
– Determine to what extent two variables, traits, or attributes are related
• Correlational coefficient (r)
– Indicates the degree of relationship between two variables
• No casual relationship can be tested
Survey
• A type of correlational study
• Usually involve a population-wide sample intending to examine public opinion
• Usually descriptive
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Naturalistic observation
• A passive descriptive study in which the presence of observer does not change or alter the
behaviors under study
• Participant observation - an observational study in which the researcher is actively involved in
the situation
• More likely for observer bias to occur
Case study
• Intensive observation of a particular individual or small group of individuals
• Examination of the person can be very detailed
• However, the results may not be generalized to other individuals
What are the pros and cons of each type of studies?
Biases and Errors
In a scientific study, data often contain errors which may include:
• Sampling error
• Placebo effects
• Experimenter bias---double-blind
• Distortions in self-report data:
–Social desirability bias
–Response set
• Confounding variables
Controlling biases and errors
• Standardization
– Set of uniform procedures for treating each participant
• Randomization
– Participants are randomly assigned to different groups
• Double-blind control
– Both the observer and the participation have no knowledge to experimental manipulation
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3) Ethical issues in Psychological research
• Informed consent
Participants should be given full information about the study before they decide to
Participate. Participation should be voluntary and withdrawal during the study is permitted.
• Minimal risk
The potential of possible harm to the participants has to be minimized.
• Deception & debriefing
If participants are deceived of anything in the study, they must be debriefed afterwards.
• Confidentiality
All information obtained in the study are highly confidential and is restricted to use for research
purposes.
• Research with animals
Should animals be used in psychological research?
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