Unit 1: History of Psychology and Research Methods 1.5 Experimental Research & Ethical Issues

Experiments Experimental Method: method where a researcher changes one variable and then observes the effect on another variable Participants receive a treatment; researches observe how the treatment affects behavior Observational vs. Experimental: Observations describe and make predictions about behavior but don’t describe the reasons behind the behavior Experiments focus on cause and effect

Variables Independent variable - the “cause” variable the factor in an experiment that researchers can change/manipulate to see the effect it causes Dependent variable - the “effect” variable - the factor that changes in response to the independent variable

Groups Experimental Group: participants who get the treatment Control Group: participants who don’t get the treatment All other conditions are as similar as possible

Try it out: Type of reading class Reading skill Amount of sleep Score on memory test Amount of walking Lung capacity Using or not using a cellphone Performance on simulated driving test The independent variable is: The dependent variable is: 1. Children’s reading skill is measured after taking either a special reading class or a standard reading class 2. College students’ memory for German vocabulary words is tested after a normal nights sleep or a night of no sleep. 3. Experiment title: “The effect of a daily walking program on elderly people’s lung capacity.” 4. People’s ability to avoid ‘accidents” in a driving simulator is tested before, during, and after talking on a cell phone.

Assignment & Bias Random Assignment: Assign participants to experimental or control group by complete chance Reduces experimenter bias Experiment Bias: Researcher’s expectations can skew results of the study Experimenter might accidently alter participant’s behavior

Assignment & Bias To reduce bias – Single-Blind Studies: participants don’t know whether they are receiving treatment or not Double-Blind Studies: participants AND researchers don’t know who is receiving treatment Placebo: participants THINK they are getting treatment, but it doesn’t actually do anything - Placebo Effect: people expectations influence their experience (if they take a placebo drug meant to help headaches, they might report feeling better after an hour)

Ethical Issues Ethics: standards for proper and responsible behavior Common ethical concerns: Informed consent – people know what they are signing up for OR they are debriefed after the experiment if deception is involved Anonymity/confidentiality – names/data kept anonymous or confidential to protect people’s privacy No long-term harm – no lasting physical or psychological harm should result (though short-term discomfort is okay)