Studying Behavior

Variable Any event, situation, behavior, or individual characteristic that varies - that is, has at least two values

Examples Variable NameLevels (values) GenderMale or Female Test Scores# correct Room Temp.Hot, Warm, Cold Room Temp.Degrees Farenheit

Operational Definition A definition of the variable in terms of the operations or techniques the researcher uses to measure or manipulate it

Values of a variable Nominal Different groups with no numeric properties Male-female, distraction-no distraction Quantitative Amounts or quantities Numerical

Relationships Between Variables Is gender related to happiness? Do males and females differ in their happiness? Is distraction while studying related to exam performance? Do people perform better when they are not distracted than when distracted?

Relationships Between Quantitative Variables Positive Negative Curvilinear No Relationship

Positive relationships Increases in the values of one variable are associated with increases in the second variable Increasing study time is associated with higher grades

Negative relationships Increases in the values of one variable are associated with decreases in the second variable Increasing hours of work are associated with lower grades

Curvilinear Relationships Increases in the values of one variable are associated with both increases and decreases of the second variable Anxiety can help increase performance until it gets to high – then it decreases perfomance

PERFORMANCE Low Moderate High ANXIETY Low High

Are the Following Relationships Positive or Negative? GPA and Tea/Cofee Consumption # of website hits and # of actual visits SAT scores and freshman GPA # hrs TV viewed and # hrs studying

Two Ways of Studying Relationships Non-experimental method Experimental method

Non-experimental Method Behavior is observed as it naturally occurs Variables are measured only Examples

Problems Direction of cause and effect Does X cause Y? Or does Y cause X? Uncontrolled third variables Perhaps Z causes both X and Y If so X and Y will appear to be related

Experimental Method Addresses the problems of inferring cause and effect Manipulate the first variable and observe the effect on the second variable Control for all other variables

Effect of IV on the DV Does distraction cause poor performance on an exam? Independent Variable “cause” variable Manipulated first Dependent Variable “effect” variable Measured as a response to the IV

Causal sequence The IV comes first The DV is then measured to examine the effect of the IV Thus, X causes Y Y could not cause X

Control Other Variables Experimental Control Variables are kept constant Randomization Randomly assign participants to conditions Run the conditions of the study in a random order Some other variable could not cause the relationship between X and Y

Advantages of the Non- Experimental Method Real life situations Prediction Study aspects of people such as personality characteristics Can study variables that would be unethical to manipulate in a true experiment

Graphing the variables Independent Variable (X axis) Place the variable you identify as the “cause” on the X (horizontal) axis Dependent Variable (Y axis) Place the variable you identify as the “effect” on the Y (vertical) axis

Identifying IVs and DVs The effects of ________ on ________. IVDV

Validity Is something “valid”? Three ways of evaluating research in terms of validity

Construct Validity Were the variables I studied adequately measured or manipulated Look at the operational definition of the variables that were studied

Internal Validity Can I infer that variable X caused variable Y? Higher internal validity with the experimental method

External Validity Can I generalize beyond this particular study? Other types of participants, other ways of studying the variables