Research Methods

1. Research Methods

2. The Scientific Attitude • 3 main components • Curiosity • Skepticism • Humility

3. The Scientific Method • A way of rigorously testing ideas against objective observations. • Psychology is a science because it uses the scientific method to test ideas empirically.

4. The Scientific Method • Empirical Investigation – The collecting of objective information firsthand by making careful measurements based on direct experience. • This is the heart of the testing procedure in the scientific method. • To investigate a question “empirically” would mean to collect evidence yourself.

5. The Goal of Psychological Science? • To develop explanations for behavior and mental processes… based on solid EMPIRICAL SCIENCE!

6. Theories • In psychology, theories are explanations for behavior and mental processes. • Definition: A testable explanation for a set of facts or observations. • Different from a speculation or guess

7. The Steps of the Scientific Method • Step 1: Develop a Hypothesis • Hypothesis: A statement predicting the outcome of a scientific study; a statement describing the relationship among variables in a study. • “Little Theory”

8. The Steps of the Scientific Method • Step 1: Forming a Hypothesis (Cont.) • Operational definitions – Specific descriptions of concepts involving the conditions of a scientific study. • Must be included in the hypothesis. • Used to check researcher bias. • Also allows others to REPLICATE the study

9. The Steps of the Scientific Method • Step 2: Performing a Controlled Test • Hypothesis must undergo a controlled test to determine whether it passes or fails. • Independent Variable – Condition that the experimenter changes independently of all the other carefully controlled experimental conditions. • The STIMULI you are studying. • Random Presentation must also occur. • Change independent variable randomly so it is unpredictable.

10. The Steps of the Scientific Method • Step 3: Gathering Objective Data • Data- Information gathered by direct observation. • Dependent Variable – The measured outcome of a study; the responses of the subjects in a study. • Comes from the assumption that the responses of participants in an experiment depend directly on the conditions to which they have been exposed. • The RESPONSE made by the participants in the experiement.

11. The Steps of the Scientific Method • Step 4: Analyzing the Results and Accepting or Rejecting the Hypothesis. • Pretty self explanatory right??? • Have to take into consideration the probability of right answers when guessing…

12. The Steps of the Scientific Method • Step 5: Publishing, Criticizing, and Replicating the Results. • Often, people try to publish scientific research, but before being published it must be critiqued and criticized by experts. • Fewer than 2% of papers on psychological research submitted to journals actually get into print without major revisions. • Some critics who are on the fence may attempt to replicate the experiment.

13. Types of Psychological Research • Experimental Method – Used to determine Cause and Effect! • Develop a research question • Survey the literature (helps for hypothesis) • Form Hypothesis • Establish Independent Variable (Part that changes) • Establish Dependent Variable (The measured outcome of a study; the responses of the subjects in a study) • Confounding or Extraneous Variable (Other things that can affect the outcome).

14. Types of Psychological Research • Experimental Method (Cont.) • Ensure Controls (Ensure all groups in the experiment are treated exactly the same). • Choose Sampling / Subjects (Must be random to represent population). • Procedure • Results / Statistics • Discussion

15. Control Group vs. Experimental Group • Control Group – Serves as a standard against which other groups can be compared. • Experimental Group – The group that is manipulated by variables in an experiment.

16. Types of Psychological Research • Non Experimental Method • Lack the control of Experimental Research Methods. • Used in situations where it may be unethical to conduct true experimental research. • Ex. – Cancer research. • Ex Post Facto – Research in which we choose subjects based on a pre-existing condition.

17. Types of Psychological Research • Correlational Studies • Mainly statistical in nature. • Determine the relationship (or correlation) between 2 variables. • Example – People who smoke are more likely to get lung cancer. • Use something called the CORRELATION COEFFICIENT to summarize the relationship between 2 variables in an experiment.

18. Types of Psychological Research • Correlational Studies (Cont) • Correlation Coefficient • Can range from a negative number as low as -1.0 to a positive number as high as +1.0. • Positive Correlation • Negative Correlation • Zero Correlation

19. Types of Psychological Research • Correlational Studies (Cont.) • Zero Correlation = No relationship between the variables. • Example – There is a zero correlation between shoe size and GPA.

20. Types of Psychological Research • Correlational Studies (Cont.) • Positive Correlation – Variables show a relationship in which they vary in the same direction (as the values of one variable increase, so do those of the other). • Example – There is generally a positive correlation of about +0.4 between SAT scores and college grades.

21. Types of Psychological Research • Correlational Studies (Cont.) • Negative Correlation – Variables show a relationship in which they vary in the opposite direction (as the value of one variable goes up, the value of the other variable goes down). • Example – A correlational study on anxiety shows a correlation of -0.7 between anxiety and time spent studying. In other words, more study is associated with less anxiety. • A negative correlation can still indicate a very strong relationship.

22. Types of Psychological Research • Surveys • A quasi-experimental method in which questions are asked to subjects. • Questions cannot be skewed or biased toward a particular answer.

23. Types of Psychological Research • Naturalistic Observation • Subjects are observed in their natural environment. • Much less control in this • Key: Must be sure subjects are not aware they’re being observed.

24. Types of Psychological Research • Longitudinal Study • One group of subjects is followed and observed for an extended period of time. • Good for investigating the long range effects of something.

25. Types of Psychological Research • Cross-sectional Study • Study in which representative cross section of the population is tested or surveyed at one specific time. • Cohort-sequential Study • Study in which a cross section of the population is chosen and then each cohort is followed for a short period of time. • Both are similar to longitudinal studies.

26. Bias in Research • Personal Bias • The researcher allowing personal beliefs to affect the outcome of a study.

27. Bias in Research • Expectancy Bias • The researcher allowing his or her expectations to affect the outcome of a study.

28. Combating Bias in Research • Double – Blind Study • An experimental procedure in which both researchers and participants are uninformed about the nature of the independent variable being administered. • Placebo involved to keep participants and researchers from forming bias.

29. Ethics in Research • Institutional Review Board – Group that reviews and approves all research to ensure no ethical violations take place. • Deception – Allowed under certain circumstances. • Participants must be debriefed afterward. • Animal Research Studies

30. Organizing Research Data • Descriptive Statistics • Statistical procedures used to describe characteristics and responses of groups of subjects.

31. Organizing Research Data • Descriptive Statistics • Measure of Central Tendency • AKA – Averages • Help us locate the center of a set of measurements.

32. Organizing Research Data • Descriptive Statistics • Measure of Central Tendency has 3 forms • Mean – The measure of central tendency most often used to describe a set of data – calculated by adding all the scores and dividing by the number of scores. • Can be distorted by extreme scores.

33. Organizing Research Data • Descriptive Statistics • Measure of Central Tendency has 3 forms • Median – A measure of central tendency of distribution, represented by the score that separates the upper half of the scores in a distribution from the lower half. • The middle score. • Not distorted by extreme scores.

34. Organizing Research Data • Descriptive Statistics • Measure of Central Tendency has 3 forms • Mode – A measure of central tendency for a distribution, represented by the score that occurs more often than any other. • Not effective when test groups are small.

35. Organizing Research Data • Descriptive Statistics • Measures of Variability • Allows us to know how well the average represents the distribution as a whole. • That is, do most of the scores cluster closely near the average or are they spread out widely. • Low Variability = All scores close to the average. • High Variability = Scores widely spread out.

36. Organizing Research Data • Descriptive Statistics • Measures of Variability • Range – The simplest measure of variability, represented by the difference between the highest and the lowest values in a frequency distribution. • Standard Deviation – A measure of variability that indicates the average difference between the scores and their mean. • The larger the score the more spread out they are. • The smaller the score the closer together they are.

37. Organizing Research Data • Inferential Statistics • Statistical techniques used to assess whether the results of a study are reliable or whether they might be simply the result of chance. • Often used to determine whether two or more groups are essentially the same or different.

38. Organizing Research Data • Inferential Statistics • To ensure accurate statistics must be sure samples are selected in an unbiased manner. • Random Sample – Sample group of subjects selected by chance. • Not always practicable. • Representative Sample – A sample group obtained in such a way that it reflects the distribution of important variables in the larger population in which the researchers are interested. • Age, income, ethnicity, and location all considered.

39. Organizing Research Data • Inferential Statistics • Significant Difference – Psychologists accept a difference between the groups as “real,” or significant, when the probability that it might be due to an atypical sample drawn by chance is less than 5 in 100. • Indicated by the notation p<.05.