Psychology 291 Lab 3 September 23 - 25, 2013 Hypotheses Variables

Hypotheses Predictions Predicted relationship (with or without direction) Correlational Predicted difference Can be Causal

Variables Measured Independent Dependent Variables that are assessed by the experimenter Correlational vs. Differential studies Quasi-Independent A pre-existing characteristic that the experimenter uses to categorize the participants e.g. Grouping Ps. according to sex Independent manipulated by the experimenter e.g. Randomly assigning Ps. to receive placebo, low dose or high dose Dependent not under the control of the experimenter the measured variable e.g. Reaction time

Variables Cont. Other variables outside the focus of the study that may affect the results Extraneous Unsystematic differences that affect the DV Confounding Variables that change systematically with IV

Confounding Variables Extraneous Variables Confounding Variables - Affect any individual in any group - Affect a group/condition within an experiment X  Y X  Individual Diff  Y Confounding Variable X acts on Individual differences leading to changes in Y Changes in X lead to changes in Y, however a relationship between X & CV influence Y

What is “Love”? Psychological Feeling warm and fuzzy Wanting to spend time with someone Caring about someone Showing interest in their interests Physiological Increased HR Increased BP Physical Arousal Sweating Behavioural Holding hands Kissing Weighted glances

Operational Definition Relates a concept to specific operations Description of the procedures followed in order to manipulate, observe or measure a variable Allows for knowing exactly what you are studying and directs how to study/measure it All variables must have an operational definition

Summary Measured Variables Hypothesis: What is being predicted? When trying to identify the hypothesis look for key words such as: Hypothesized Objective Investigate Measured Variables Assessed by the experimenter Pre-existing characteristic or measured The independent variable is manipulated or if quasi-independent allows for categorization. IV: What did the researchers change in order to group participants? QV: What characteristic did researchers use to group the participants? The dependent variable is what changed as a result of the manipulation. What were researchers trying to find/elicit a change in?

A drug company is advertising a new drug that helps people recover from jet lag faster. You are skeptical, so you conduct an experiment to test their claim. In your experiment, 100 people are flown from San Francisco to Tokyo. During the flight, half of the participants are given the drug company’s new drug. The other half of the participants are given a placebo during the flight. Six hours after they land, all participants are asked to rate how sleepy and disoriented they feel.