Research Methods Lecture Notes PDF

Research Methods Why do we need psychological science? Aren’t most psychological findings common sense? Popular wisdom and common sense can lead to erroneous conclusions Consider the following examples of popular wisdom: – Birds of a feather flock together – Opposites attract We experi...

Research Methods Why do we need psychological science? Aren’t most psychological findings common sense? Popular wisdom and common sense can lead to erroneous conclusions Consider the following examples of popular wisdom: – Birds of a feather flock together – Opposites attract We experience hindsight bias – overestimation of the ability to have predicted an outcome The scientific method Tests ideas with the use of data – evidence (empiricism) Steps in the research process: 1. Formulate the research question 2. Formulate the hypothesis Hypothesis - testable prediction The scientific method 3. Design the study to test the hypothesis Operational definition – statement about the procedures the researcher used to measure a variable 4. Perform the study (test the hypothesis) 5. Interpret the data (draw conclusions) 6. Communicate the findings Research strategies – descriptive methods Case study – in-depth analysis of one subject (or more) Phineas Gage Research strategies – descriptive methods Observation Describe and measure people and/or animals’ behavior systematically E.g., observe behavior of parents dropping off kids at day care Research strategies – descriptive methods Survey Asking people questions about their thoughts, feelings, desires, and actions and recording their answers Problems: Wording Response bias – pattern of responses to questions that does not accurately reflect the content of the question Random sampling (a.k.a. random selection) – everyone in the population has an equal chance of being in the sample Correlational method Correlation – measures strength and direction of relationship between two variables Direction: Positive correlation: variables change in the same direction Negative correlation: variables change in opposite directions Correlation coefficient (r) – indicator of the strength of the relationship between two variables (ranges from -1.00 to +1.00)  Correlation Correlation does A B not necessarily indicate causation!!! B A – Instead of A causing B, B could cause A C A – There could be a third variable, C, which could be B causing both A and B Experimental method Experiment – researcher changes (manipulates) one variable and measures the effects of that change on another variable Only research design in which cause and effect can be inferred!! – Independent variable (IV) – manipulated by experimenter – Dependent variable (DV) – outcome variable Purpose: test the effects of the IV on the DV Does the IV cause the DV? Experimentation Experimental (treatment) condition (group) – receives treatment/stimulus Control condition (group) – does not receive treatment/stimulus (comparison group) Experimentation Confounding variable – variable that is potentially responsible for the results, but is not the variable of interest (the IV) Random assignment – method used to place participants into experimental condition in which participants have an equal chance of being in every condition Experimental control – researcher makes sure that no factors other than the IV are changing and thus could affect the DV Experimentation Placebo effect – observed improvement following an inert treatment Placebo control group – participants who receive placebo rather than actual treatment or nothing Expectancy effect (type of experimenter bias) – results when the experimenter’s hypothesis (expectation) leads unintentionally to behavior toward the participants that then increases the likelihood that the participants’ behavior will confirm the hypothesis (e.g., Rosenthal & Jacobson, 1968) Experimentation Single-blind procedures – the participants do not know if they have been assigned to the experimental or control group Double-blind procedures – neither the participants nor the researchers know who has been assigned to the experimental or control group  Confounds practice 1. Researchers want to test whether mountain climbing will increase self-esteem in juvenile offenders. A one-week mountain climbing expedition to the Pocono Mountains is planned. Twenty-five early teenagers (age 13-14) in a New Jersey youth detention facility were assigned to the experimental group. Twenty-five mid-teenagers (age 15-16) from a Pennsylvania youth detention facility will serve as the control group. All participants will be tested daily on self-esteem as measured by a questionnaire. ❖ Potential confound(s)?  Confounds practice 2. The local school district wants to compare three anti-smoking programs used at the sixth grade level. The superintendent makes the following assignments: School 1 will view a film program that features celebrities promoting the anti-smoking message, School 2 will listen to guest lecturers who are suffering from lung cancer in an assembly, and School 3 will receive training in a workshop on resisting peer pressure during physical education classes. After the program, all students will be surveyed about their smoking behavior. ❖ Potential confound(s)? Important issues in research Generalizability of an outcome to other groups and settings Can the results apply to other situations? Replication – repetition of a study Do you see any potential problems? A clinical psychologist strongly believes that calming music is an important adjunct to successful therapy. For two months, he plays calming music during sessions with half of his clients (Group A) and does not play music during sessions with the other half (Group B). He then reports a noticeable improvement in Group A. After reading a scientific article that reports higher divorce levels among couples who lived together before marriage, a college student decides to move out of the apartment she shares with her partner. To measure whether subliminal messages about beverages would increase beverage sales, a theater owner briefly flashed subliminal messages (such as “Drink Coca-Cola”) during a film and reported high beverage sales following the film.