Adapted from Supplemental Resource © Allyn & Bacon Chapter Two: Research Methods

How Do Psychologists Develop New Knowledge? Psychologists, like researchers in all other sciences, use the scientific method to test their ideas empirically

There’s Method in this Madness! Scientific method- putting one’s ideas to an objective test.Scientific method- putting one’s ideas to an objective test.

Copyright © Allyn & Bacon 2007 Scientific method A five-step process for empirical investigation of a hypothesis under conditions designed to control biases and subjective judgments

Empirical Investigation - An approach to research that relies on sensory experience and observation as research data An approach to research that relies on sensory experience and observation as research data Empirical = Experience We should investigate…

The Five Steps of the Scientific Method Developing a hypothesis Performing a controlled test Gathering objective data Analyzing the results Publishing, criticizing, and replicating the results

Theory- a testable explanation for a set of facts or observations. In science, a theory is not justIn science, a theory is not just speculation or a guess. The main goal of psychological science is to develop explanations for behavior and mental processes… That are based upon solid empirical studies, not hunches or guesses Theoretically speaking…

Developing a hypothesis Performing a controlled test Gathering objective data Analyzing the results Publishing, criticizing, and replicating the results Step 1: “I’ve got an idea!” Hypothesis – a prediction based on observation The Five Steps of the Scientific Method

Not a big theory, but a “little one” Hypothesis- must be testable and falsifiable (can be proven false by an observation or a physical experiment) A hypothesis is only taken seriously only after it has been subjected to rigorous testing Often representative of a larger theory

“I was trying to operate on your funny bone, but I’m sure our definitions differ.” Operational definitions- Exact procedures used in establishing conditions and the measurement of results in an experiment. Defining the Operation

Developing a hypothesis Performing a controlled test Gathering objective data Analyzing the results Publishing, criticizing, and replicating the results Independent Variable - The stimulus you are studying A condition that the experimenter changes independently of all the other carefully controlled conditions Step 2: Put it to the test

Independent Variable vs. Dependent Variable Independent Variable The stimulus you are studying Dependent Variable The measured outcome of a study The responses made by the participants in your experiment For example… --In a study of how different drug dosages affect the symptoms of a disease, the administration of the drug in specified doses is the independent variable. -- The severity of the disease’s symptoms is the dependent variable.

Copyright © Allyn & Bacon 2007 The independent variable here is: the amount of light The dependent variable here is: how much the plants grow

Copyright © Allyn & Bacon 2007 That’s so random Random Presentation- using chance alone to determine the order in which the stimulus is presented Example: Flip a coin to choose the left or right hand of a subject Reduces experimenter bias

Copyright © Allyn & Bacon 2007 Developing a hypothesis Performing a controlled test Gathering objective data Analyzing the results Publishing, criticizing, and replicating the results Data – Information gathered by researcher and used to test a hypothesis Step 3: Data collection Gathered by direct observations

Replicate: Doing a study over to see whether the same results are obtained Doing a study over to see whether the same results are obtained As a control for bias, As a control for bias, replication is often replication is often done by another done by another researcher. Quantified:Quantified: Measured and expressed by numbers Measured and expressed by numbers

Developing a hypothesis Performing a controlled test Gathering objective data Analyzing the results Publishing, criticizing, and replicating the results Based on analyses of results, the hypothesis is accepted or rejected. Step 4: Analysis

Developing a hypothesis Performing a controlled test Gathering objective data Analyzing the results Publishing, criticizing, and replicating the results Step 5: Publish and Be Criticized Researchers must find out whether their work can withstand the scrutiny of the scientific community

I forgot my lab coat… again Experimental Method- A kind of research in which the researcher controls all the conditions and directly manipulates the conditions, including the independent variable.

Look at all the cons I found… Confounding / Extraneous Variables- Variables that have an unwanted influence on the outcome of an experiment We attempt to overcome these by using control procedures.

Back to the control room… Controls- constraints that the experimenter places on the experiment to ensure that each subject has the exact same conditions and is treated the same

Random Assignment (not of the bizarre homework variety) Each subject of the sample has an equal likelihood of being chosen for the each group used in the study… … the experimental group vs. the control group

Random Sample Every member of the population has an equal chance of being selected for the study sample Every member of the population has an equal chance of being selected for the study sample Random Assignment Each subject of the sample has an equal likelihood of being chosen for the each group Each subject of the sample has an equal likelihood of being chosen for the each group Random Presentation Using chance alone to determine the order in which the stimulus is presented

Ethically, I just can’t do it… Non-Experimental Methods Ex post facto design- Research in which subjects are chosen based upon a condition that they already have Example: cancer patients chosen to test a new drug

Non-Experimental Methods Naturalistic Observation The subjects are observed in their natural environment The subjects are observed in their natural environment People should not be aware that they are being observed….they will act differentlyPeople should not be aware that they are being observed….they will act differently

Longitudinal Study A type of study in which one group of subjects is followed and observed for an extended period of time (years)A type of study in which one group of subjects is followed and observed for an extended period of time (years) A class of 1st graders to their high school graduationA class of 1st graders to their high school graduation

Can you relate? Correlational study- a type of research that is mainly statistical in natureCorrelational study- a type of research that is mainly statistical in nature They determine the relationship, or correlation, between two variablesThey determine the relationship, or correlation, between two variables

The Errant Notice October 12, 2007 “Kids Crazed by Chicken Fingers”

Obesity and Fast Food

Degree of Correlation Often expressed as a numberOften expressed as a number Low correlation: -1.0Low correlation: -1.0 High correlation: +1.0High correlation: +1.0 Zero correlation: 0Zero correlation: 0

Is there a correlation between intelligence and beauty pageant contestants?

Let’s find out… See Miss Teen USA videoSee Miss Teen USA video xZ8Dwwhttp:// xZ8Dwwhttp:// xZ8Dwwhttp:// xZ8Dww

n n Zero Correlation: Shoe size and IQ n : n Positive correlation: SAT scores and college grades n n Negative Correlation: More studying and less test anxiety n n A correlation can show a strong relationship even when it is negative n n A -0.7 is stronger than a +0.4

Cohort-Sequential Study A research method in which a cross-section of the population is chosen and then each cohort (group) is followed for a short period of time Ex: Get a large group of people. Collect data on several factors (such as what they eat, drink, etc..). Record who gets cancer and who does not. Can take less time than a longitudinal study, is much less susceptible to bias, and yields more accurate data than a cross-sectional study

Survey says… Survey- a quasi-experimental method in which questions are asked to subjectsSurvey- a quasi-experimental method in which questions are asked to subjects When creating a survey, the researcher must be careful that the questions are not slanted or biased toward a particular answer. When creating a survey, the researcher must be careful that the questions are not slanted or biased toward a particular answer.

Can I see a cross-section? Cross-Sectional Study- a study in which a representative cross section of the population is tested or surveyed at one specific time.Cross-Sectional Study- a study in which a representative cross section of the population is tested or surveyed at one specific time. Example: Look at a group of people…see who eats fast food and who is obese Will yield data similar to a longitudinal study but not so accurateWill yield data similar to a longitudinal study but not so accurate

Case Study- when one individual is studied closely to identify behavioral, emotional, and/or cognitive qualities that are universally true of others.Case Study- when one individual is studied closely to identify behavioral, emotional, and/or cognitive qualities that are universally true of others. Method primarily used by the clinical approachMethod primarily used by the clinical approach Ex: observing a five-year-old in various situationsEx: observing a five-year-old in various situations (Just in case…)

Sources of Bias Sources of bias include: Personal bias Personal bias Expectancy bias Expectancy bias Bias could affect the way an experimenter designs a study, collects data, or interprets results Double blind studies attempt to control bias Researchers must also attempt to control confounding variables

It’s totally personal… Personal Bias- the researcher’s individual beliefs, feelings, preferences, assumptions, or prejudices that may affect the construction of a study Most of the time, it is not obvious to the individual.

Or it could be my expectations… Expectancy Bias- a researcher’s expectations that may affect the outcome of a study Occurs when observers expect, and look for, certain outcomes Sounds like _________________ to me

The Blind Leading the Blind The Blind Leading the Blind Single-Blind Study: A study in which the subjects are uninformed if they are receiving the treatment or a placebo A study in which the subjects are uninformed if they are receiving the treatment or a placebo Double -Blind Study: A study in which the subjects and the researchers are uninformed if they are receiving the treatment or a placebo A study in which the subjects and the researchers are uninformed if they are receiving the treatment or a placebo

Gimme some sugar (pills) A placebo is any substance that produces no meaningful chemical or biological changes in an organism that is made to look like a "real" drug. Scientists often give placebos to determine if an effect is due to the "real" drug or from the act of just taking a pill. Placebo Effect: A response to a placebo caused by the subjects belief that they are taking real drugs

The Ethical Psychologist Institutional Review Board (IRB)- a committee that reviews every experiment at a research institution for ethics and methodology Institutional Review Board (IRB)- a committee that reviews every experiment at a research institution for ethics and methodology Institutional Animal Care and Use Committee: (IACUC)- a committee at each institution that reviews every experiment involving animals at a research institution for ethics and methodology Institutional Animal Care and Use Committee: (IACUC)- a committee at each institution that reviews every experiment involving animals at a research institution for ethics and methodology

Deception

“I’ll be brief. We just tricked you. Why, you ask? Because we can.” Debriefing- a one- time conversation with an individual who has been deceived for research purposes Debriefing- a one- time conversation with an individual who has been deceived for research purposes

Ethics: Animal Research

Questions Science Cannot Answer The scientific method is not appropriate for answering questions that cannot be put to an objective, empirical test. EthicsEthics MoralityMorality Religious beliefsReligious beliefs PreferencesPreferences The meaning of lifeThe meaning of life

End of Part One Stats are coming…