2.  Basis of scientific method ◦ Making observations in systematic way (empirical studies) ◦ Follow strict rules of evidence ◦ Critical thinking about evidence Research Methods In Psychology

3.  Aim ◦ Purpose of the Study  Target Population ◦ Group whose behavior is investigated  Procedure ◦ A step by step process taken to carry out the study  Findings ◦ How the researcher interpreted the data collected

4.  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 Research Methods In Psychology

5.  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 In Psychology

6.  Opportunity Sample ◦ Convenience sampling: sample of whoever agrees to participate ◦ Prone to sampling bias

7.  Self-Selected Samples ◦ Volunteers ◦ Easy to obtain ◦ Rarely reflects the general population  Snowball Sampling ◦ Participants recruit other participants

8.  Participant Variability ◦ The extent to which the participants may share a common set of traits that can bias the outcome of the study

9.  Random Sampling ◦ Every member of the target population has an equal chance of being selected ◦ Able to be generalized to the larger population  Stratified Sample ◦ Drawing random samples from each population within the target population ◦ Provides for a more accurate representation

10.  Be a researcher (Crane, p.21)  If you use an opportunity sample at a local fitness center, which group of people would be overrepresented? Which group would be underrepresented?  Would you get a more representative sample if you advertised for participants in your school?

11.  Descriptive or Qualitative 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 In Psychology

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

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

14. Fig. 2.2 Variable 2 21 Variable 1 22 23 24 25 26 27 28 29 30 2 20 3456789101 Hypothetical data illustrating a correlation coefficient of +1.00

15. Fig. 2.3 Hypothetical data illustrating a correlation coefficient of -1.00 Variable 2 21 Variable 1 22 23 24 25 26 27 28 29 30 2 20 3456789101

16. Fig. 2.4 Hypothetical data illustrating a correlation coefficient of zero Variable 2 21 Variable 1 22 23 24 25 26 27 28 29 30 2 20 3456789101

17.  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 Research Methods In Psychology

18.  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 Research Methods In Psychology

19. 0.02 Nonviolent film Violent film 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.00 Fig. 2.6

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

21.  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 Research Methods In Psychology

22.  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 Research Methods In Psychology

23. 1 2 3 4 5 6 7 8 9 40 0 131619222528313437 % Giving birth for 1st time Mother’s Age Mode Mean & Median

24.  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 Research Methods In Psychology

25.  Ethics in research with human participants ◦ Freedom from coercion ◦ Informed consent ◦ Limited deception ◦ Adequate debriefing ◦ Confidentiality Research Methods In Psychology

26.  Ethics of research with nonhuman animals ◦ Necessity ◦ Health ◦ Humane treatment Research Methods In Psychology

27.  Key features: ◦ High degree of researcher/experimenter control ◦ The only method which establishes cause & effect ◦ Can have problems with ecological validity, artificial ◦ Provides quantitatve data

28.  Quantitative data can be ‘quantified’ and counted  Qualitative describes  Which is which of the following? ◦ Scores in a memory task ◦ Participants’ childhood memories of Christmas ◦ Case study written up by therapist about a client’s repressed memories ◦ Number of errors made in a memory task

29.  Watching what is going on – easy peasy?  Monty Python ‘argument’ sketch Monty Python ‘argument’ sketch  Different observers might disagree on criteria?  Should those being observed know (overt) or should it be done without their knowledge (covert)?  Should the researcher take part (participant) or not (non-participant)?  Can generate quantitative or qualitative data – how?

30.  Easy to do?  Usually ‘highly structured’, i.e. fixed questions with limited responses  May use ‘Likert scale’ to measure attitudes  What type of data does this generate?  Can we trust the answers

31.  Related to surveys & questionnaires, but usually face to face  Can use different types of questions, from highly structured (surveys) to unstructured, participant-led (e.g. therapy sessions)  Most are semi-structured, i.e. some questions are prepared in advance, but these are flexible and can be adapted to follow areas of interest  What type of data does this generate?

32.  These are a less common method, usually used in clinical or therapeutic situations, e.g. studying memory loss in individuals with brain injuries  Gather a wide range of information about one individual or event (e.g. 9/11)  Why would this method be used? What type of data would it generate?