Experimental Methods in PsychologyExperimental Methods in Psychology

Experimental Methods- Science and Psychology

One method of psychological research is naturalistic observation, which follows the idea of Darwin and other naturalists. Psychologists, wanting to determine the cause of a behavior, could directly observe the behavior and hypothesize as to possible causes

Experiments are conducted to determine and test the specific causes of a behavior

They allow psychologists to specifically control conditions and manipulate variables to test a hypothesis

Experiments can be observational and are sometimes inexact- How would one go about measuring aggression, for example?

Simple Correlation

Correlation- the measure of the relationship between two variables

Correlation coefficient- a number between -1 and 1 that describes the relationship.

A coefficient closer to 1 means that there is a more perfect correlation between variables. A correlation closer to negative one means that the variables vary inversely: as one goes up, the other decreases

Steps to Designing Psychological Experiments

Step 1- Directly vary the condition which is thought to affect behavior

Step 2- Create two different groups of subjects- experimental and control group- which should be identical in makeup and conditions except for the variable that the researcher is manipulating

Step 3- Record whether manipulating that condition has any effect on the behavior

Variables

Independent variables- the variable that you control in an experiment, often a hypothesized cause of a behavior

Dependent variable- what you are trying to measure, reveals the effects of the independent variable

Extraneous variables- conditions that researchers wish to prevent from effecting the outcomes of their experiments- anything that can skew your results

Interpreting your results

Correlation does NOT mean causation- experiments must be tested for statistical significance

Experiments are more believable when they are less likely to occur by chance- so statistical tests are run to determine these probabilities

To be statistically significant an experiment usually has to have less than a 5 percent chance of occurring by chance

If statistical significance exists, then causation between the independent and dependent variable is established

The easier an experiment is to reproduce, the more likely its results will be taken seriously

Sources of Bias

Participant Bias

Participant bias- the phenomenon that a group of participants displays changes in behavior due to expectations and regardless of the independent variable.

Placebo- a “dummy” drug, substituted for the independent variable and given to the control group in an experiment

Placebo effect- a phenomenon where people display changes in behavior or biological changes despite the fact that they are receiving a placebo

Single blind experiments- controls for participant bias. SB experiments do not disclose the hypothesis being tested for or which group is receiving placebo to the participants

Researcher Bias

Researcher bias- Researchers run the risk of unintentionally effecting the results of their participants or unintentionally finding what they were looking for.

Self fulfilling prophecies- Participants are often sensitive to what is being expected of them and will pick up subtle clues that hint as to expected behaviors, then tend to behave that way. Anything from tone of voice, to body language can provide a clue and skew results.

Double blind experiments- can help control for Researcher bias. Neither researcher nor participants know which group receives placebo.

Research Ethics

Ethics- a code of behavior by which one should abide, in this case, researchers

Ethical experiment- an experiment that treats its participants well and abides by commonly accepted rules in the scientific community

Examples of good ethics are: experiments that don't hurt the participants mentally or physically, experiments that do not hurt animals or cause undue suffering.

Clones from Aliens 4 -->

Unethical Experiments Unethical experiments fail to abide

by commonly accepted scientific conventions on the treatment of humans or animals, the creation of life, causing suffering, or other significant arguments

Some unethical experiments could provide substantial benefit to science or psychology, but are not performed because of arguments in the scientific community. Cloning is a good example of this.

Other unethical experiments are just poor planning such as the Milgram experiments in the 1960's that were testing human tendencies to accept or reject authority

Picard's Reaction to Milgram: The dreaded double facepalm