3 Research Strategies in Psychology: Descriptive Correlational Experimental

3 Research Strategies in Psychology: Descriptive: Descriptive – includes methods that enable researchers to observe & describe behaviors and mental processes w/o manipulating variables; do NOT enable researchers to establish cause & effect relationships Surveys Naturalistic Observation Case Studies Development Studies (Longitudinal & Cross Sectional) Cause & Effect

Survey Method: Most common type of study in psychology Descriptive Research… Survey Method: Most common type of study in psychology Measures correlation Cheap and fast Need a good random sample Low-response rate

Descriptive Research… Surveys: Measure the self-reported attitudes or behaviors of a randomly selected representative sample of an entire group or population Research technique that uses questionnaires or interviews or a combination of the 2 to assess the behavior, attitudes, and opinions of a large number of people Wording of questions / wording effects– important factor in the validity of survey research, ex: framing Social desirability bias – survey respondents often report that they are healthier, happier, and less prejudiced than would be expected based upon the results of other types of research

Naturalistic Observation Descriptive Research… Naturalistic Observation Watch subjects in their natural environment. Do not manipulate the environment. The good is that there is Hawthorne effect. The bad is that we can never really show cause and effect.

Naturalistic Observation: Descriptive Research… Naturalistic Observation: Seeks to observe & record the behavior of organisms (including humans) in their natural environments Researchers unobtrusively observe the behavior of subjects as it occurs in a real social setting Provides a slice of life that can be very revealing Descriptive research: DO NOT EXPLAIN BEHAVIOR Using naturalistic observation of walking speed & the accuracy of public clocks, researchers have concluded that the pace of life varies from one culture to another Researchers have also found that people are more likely to laugh in social situations than in solitary situations

Case Studies A detailed picture of one or a few subjects. Descriptive Research… Case Studies A detailed picture of one or a few subjects. Tells us a great story…but is just descriptive research. Does not even give us correlation data. The ideal case study is John and Kate. Really interesting, but what does it tell us about families in general?

Case Study: In-depth examination of a single research participant Descriptive Research… Case Study: In-depth examination of a single research participant Enable researchers to obtain detailed knowledge about a person; Provide an opportunity to conduct in-depth studies of rare or unusual cases CANNOT be used to establish cause & effect relationships Susceptible to inaccurate reporting and the subject’s biased views

Longitudinal Studies: Descriptive Research… Longitudinal Studies: Development Study Measures a single individual or group of individuals over an extended period of time Ex: a longitudinal study of intelligence would retest the same people over a period of years Provide in-depth information Can be expensive & time consuming One group of people studied over a long period of time. Pros: same group of people Cons: people drop out (quit, move, die); takes a long time, expensive

Cross Sectional Studies: Descriptive Research… Cross Sectional Studies: Development Study Cross sectional method - compares individuals of various ages at one point in time EX: a cross-sectional study of achievement motivation would test 8th, 10th, and 12th grade students at the beginning of the school year Provide information about age differences Difficult to make generalizations since cross-sectional studies measure behavior at only one point in time Participants of different ages studied at the same time. Pros: fast; cheaper Cons: different people so changes may be due to confounding variables

3 Research Strategies in Psychology: Correlational Method Correlation expresses a relationship between two variable. Does not show causation. As more ice cream is eaten, more people are murdered. Does ice cream cause murder, or murder cause people to eat ice cream?

Types of Correlation Positive Correlation The variables go in the SAME direction. Negative Correlation The variables go in opposite directions. Studying and grades hopefully has a positive correlation. Heroin use and grades probably has a negative correlation.

Correlation Coefficient A number that measures the strength of a relationship. Range is from -1 to +1 The relationship gets weaker the closer you get to zero. Which is a stronger correlation? -.13 or +.38 -.72 or +.59 -.91 or +.04

Correlational Research: 3 Research Strategies in Psychology: Correlational Research: Correlational- researchers observe or measure a relationships b/w variables in which changes in one variable are reflected in changes in the other variable; correlation studies do not directly manipulate variables; correlations can be used to analyze data gathered in any type of descriptive method The Golden Rule: Correlation does NOT prove Causation!!!

Correlational Research… Correlational Coefficient – numerical value that indicates the strength b/w variables in which changes in one variable are reflected in changes in the other variable; Calculated by a formula that produces a number ranging from +1.00 to -1.00 Positive Correlation – indicates that 2 variables move or vary in the SAME direction EX: Studies have found a positive relationship b/w smoking & the incidence of lung cancers; that is, as frequency of smoking increases, so does the incidence of lung cancer Negative Correlation – indicates that 2 variables move or vary in OPPOSITE directions; EX: studies have found a negative correlation b/w level of education an danger; that is as level of education increases, expressions of anger decrease Zero Correlation – indicates that there is NO RELATIONSHIP b/w 2 variables EX: A study by Isabelle Deltour for the Danish Cancer Society found no correlation b/w cello phone use & incidence of brain tumors

Correlation does NOT prove Causation: Correlational Research… Correlation does NOT prove Causation: Correlation studies indicate the possibility of cause & effect relationships (but they do NOT prove cause & effect!) Correlation does NOT prove causation!!! Ex: Studies have found a moderate correlation of +.4 b/w SAT scores & college grades, however this correlation does not tell us if high SAT scores cause high college grades. Other known & unknown factors, such as level of achievement motivation and the presence or absence of tutors, could be responsible for both the SAT scores & college grades

Advantages of Correlation Studies: Correlational Research… Advantages of Correlation Studies: Can be used to describe or clarify a relationship b/w 2 variables Efficient way to utilize preexisting data Can be used to dispel illusory correlations – although widely believed, an illusory correlation is in fact non-existent. EX: it is widely, but erroneously believed that there is a correlation b/w date of birth & personality traits

Disadvantages of Correlation Studies: Correlational Research… Disadvantages of Correlation Studies: CANNOT be used to establish cause & effect relationships CANNOT be used to establish the direction of causal influence Do NOT allow researchers to actively manipulate the variables Make it difficult to identify the impact of confounding variables

3 Research Strategies in Psychology: Experiments: Experiment – carefully controlled method of investigation used to establish cause & effect relationships Experimenter purposely manipulates & controls selected variables in order to determine cause & effect Independent variable – factor that is manipulated or controlled by the experimenter Dependent variable – the factor that is measured by the experimenter; it is affected by, and thus, dependent on the independent

Experimental Method Looking to prove causal relationships. Cause = Effect Laboratory v. Field Experiments Smoking causes health issues.

Beware of Confounding Variables The object of an experiment is to prove that A causes B. A confounding variable is anything that could cause change in B, that is not A. If I wanted to prove that smoking causes heart issues, what are some confounding variables? Lifestyle and family history may also effect the heart.

Random Assignment Once you have a random sample, randomly assigning them into two groups helps control for confounding variables. Experimental Group v. Control Group. Group Matching

Hawthorne Effect But even the control group may experience changes. Just the fact that you know you are in an experiment can cause change. Whether the lights were brighter or dimmer, production went up in the Hawthorne electric plant.

Experimenter Bias Another confounding variable. Not a conscious act. Double-Blind Procedure.

Other Confounding Variables Placebo effect Order Effects