Research Methods In Psychology 2 Research Methods In Psychology

Basic Concepts of Research Research Methods In Psychology Basic Concepts of Research Basis of scientific method Making observations in systematic way Follow strict rules of evidence Critical thinking about evidence

Empirical Evidence and Operational Definitions Research Methods In Psychology Empirical Evidence and Operational Definitions Empirical evidence – observations of publicly (confirmable) observable behavior Operational definitions – use operations of measurement to describe observations Evaluates quality of evidence and allows alternative interpretations

Theories and Hypotheses Research Methods In Psychology Theories and Hypotheses Theories – tentative explanations of facts and relationships in science Hypothesis – a prediction based on a theory Tested to confirm or refute Can be revised or abandoned

Representativeness of Samples Research Methods In Psychology Representativeness of Samples Sample Representative of larger group or population of interest Small group of humans or animals Unrepresentative sample – misleading or biased test of hypothesis Replication of research removes most doubt

Research Methods Descriptive studies Research Methods In Psychology Research Methods Descriptive studies Simplest method of scientific inquiry Describe behavior and mental processes Most widely used Survey method – ask people’s opinions Naturalistic observation – watch, describe Clinical method – observe in clinic setting All have advantages and disadvantages

Research Methods Correlational Studies Research Methods In Psychology Research Methods Correlational Studies Correlational method: measure two variables for statistical relationship Variable: anything that can be assigned a numerical value Uses quantitative measures

Research Methods Correlational Studies Correlation coefficient Research Methods In Psychology Research Methods Correlational Studies Correlation coefficient Measures each variable Indicates strength ( 0 to 1) and direction (negative or positive) of relationship Correlation does not mean causation

Hypothetical data illustrating a correlation coefficient of +1.00 Fig. 2.2 Variable 2 21 Variable 1 22 23 24 25 26 27 28 29 30 2 20 3 4 5 6 7 8 9 10 1 Hypothetical data illustrating a correlation coefficient of +1.00

Hypothetical data illustrating a correlation coefficient of -1.00 Fig. 2.3 Variable 2 21 Variable 1 22 23 24 25 26 27 28 29 30 2 20 3 4 5 6 7 8 9 10 1 Hypothetical data illustrating a correlation coefficient of -1.00

Hypothetical data illustrating a correlation coefficient of zero Fig. 2.4 Variable 2 21 Variable 1 22 23 24 25 26 27 28 29 30 2 20 3 4 5 6 7 8 9 10 1 Hypothetical data illustrating a correlation coefficient of zero

Formal Experiments Tests relationship of two or more variables Research Methods In Psychology Formal Experiments Tests relationship of two or more variables Allows conclusions about cause-and-effect Quantitative measures of behavior compared in different conditions created by researchers Evidence supports or rejects hypothesis

Formal Experiments Elements Independent variable – gets manipulated Research Methods In Psychology Formal Experiments Elements Independent variable – gets manipulated Dependent variable – amount of change Experimental group – exposed to independent variable or conditions expected to create change Control group – presents normal behavior used for comparison Random assignment Experimental control

Fig. 2.6 Nonviolent film Violent film 0.16 0.14 0.12 0.10 0.08 0.06 0.02 Nonviolent film Violent film 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.00

Randomly assign into control and experimental groups Fig. 2.7 Full population of interest Randomly assign into control and experimental groups Experimental group: exposed to independent variable: view violent film Control group: View nonviolent film

Formal Experiments Placebo control Blind experiment Research Methods In Psychology Formal Experiments Placebo control Placebo effect: provides no active effect Use in identical conditions for control and experimental groups Blind experiment Researchers blind to group membership of participants to rule out experimenter bias Strongest experiments – double blind Researchers and participants kept blind

Describing and Interpreting Data Research Methods In Psychology Describing and Interpreting Data Descriptive statistics – summarized data for large groups of participants Mean: average Median: midpoint in rank-ordered data Mode: score appearing most often Normal distribution: bell-shaped curve Standard deviation: degree to which scores in ordered distribution are spread out

% Giving birth for 1st time 2 3 4 5 6 7 8 9 40 13 16 19 22 25 28 31 34 37 % Giving birth for 1st time Mother’s Age Mode Mean & Median

Describing and Interpreting Data Research Methods In Psychology Describing and Interpreting Data Reaching conclusions from data Statistical significance Size of correlation Difference of means are greater than chance Two issues for significance Larger sample size is better Statistical difference does not equal practical significance

Ethical Principles of Research Research Methods In Psychology Ethical Principles of Research Ethics in research with human participants Freedom from coercion Informed consent Limited deception Adequate debriefing Confidentiality

Ethical Principles of Research Research Methods In Psychology Ethical Principles of Research Ethics of research with nonhuman animals Necessity Health Humane treatment

Human Diversity: Equal Representation in Research Research Methods In Psychology Human Diversity: Equal Representation in Research U.S. National Institutes of Health New applications for research grants involving human subjects must include diverse samples of Both sexes Major racial and cultural groups Differences may be real and important

Research Methods In Psychology 2 The End