Presentation on theme: "AP Psychology September 15, 2014. The Scientific Method - in Psychology Starts with a THEORY An explanation using an integrated set of principles."— Presentation transcript:
The Scientific Method - in Psychology Starts with a THEORY An explanation using an integrated set of principles that organizes observations and predicts behaviors or events E.g. The root of depression is low self-esteem. Theory produces testable predictions, called HYPOTHESES. They give direction to research. They specify what results would support or disconnfirm the theory. E.g. People who report poorer self-image on a particular scale would score higher on a depression scale.
The Scientific Method - in PSYCHOLOGY, cont’d. Testing can be one of three types: DESCRIPTIVE CORRELATIONAL EXPERIMENTAL Eventually, testing leads to a revised theory, which better organizes and predicts what we know about the topic.
Types of Studies They vary by purpose and methodology. Three main types: Experimental Correlational Descriptive
EXPERIMENTAL STUDIES Only way to study cause and effect One or more factors are manipulated in order to observe cause & effect Factor that is manipulated = INDEPENDENT VARIABLE Factor that is being tested (or depends on the independent variable) = DEPENDENT VARIABLE
“Conditions” in an Experiment Experimental exposed to independent variable Control not exposed to independent variable serves as a comparison
Variables Which variable is which? In a study to determine the effects of caffeine consumption on class participation In a study to determine the effects of video game playing on aggressive behavior In a study to determine the effect of a certain medication on anxiety symptoms
How are variables measured in an experiment? Operational definitions Specify precisely what procedures will be used to measure and manipulate variables E.g. “Hunger” = “hours without eating” This allows for REPLICATION (repeating the study in a different situation)
How do researchers ensure the groups are “equal”? Random assignment Putting subjects into experimental and control conditions by chance Minimizes preexisting differences Allows researchers to say that results are probably due to manipulation of the independent variable