Identify the typical steps followed when performing an experiment in psychology.
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1. Psychologists use the scientific method as an organized decision-making process when doing research. For example, suppose that a group of researchers has observed that sleepy college students don't seem to perform well on tests. The researchers' curiosity turns this “interesting observation” into a systematic program of research.
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2. The researchers might begin by forming a simple theory to explain the students' behavior, such as, "Adequate sleep enhances memory and thinking."
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3. Then, they would construct a hypothesis (testable prediction) derived from the theory, such as, "Students who sleep more than 6 hours will score higher on a memory test than those who get fewer hours of sleep."
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4. The next step would be to perform an experiment to test the hypothesis. After recruiting a sample of college students, the researchers would manipulate the independent variable (sleep) by using random assignment to place half the students in the experimental group, or condition (allowed to sleep 7 hours), and half in the control (comparison) group (allowed to sleep 5 hours).
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5. Both groups would be given a list of psychology terms and definitions to study for one hour in the evening. Then, the groups would be allowed to go to sleep. After the specified number of hours of sleep, each group would be awakened and given a quiz on the list of terms. The researchers would then perform a statistical test on the results to determine whether there was a significant difference between the groups in terms of the dependent variable (memory performance).
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6. If the results did not support the hypothesis, the researchers would revise the theory, derive a new hypothesis from the theory, and test it.
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7. If the results did support the hypothesis, the researchers would probably try to publish their results in a scientific journal. Then, other researchers in different locations would try to replicate the results (repeat the experiment with different students or slightly different procedures). If the results could not be replicated, the scientific community would eventually reject the theory. Researchers would perhaps form a new theory to explain the original “interesting observation,” and the entire process would start over.
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8. On the other hand, if other researchers successfully replicated the findings of the first group of researchers, the scientific community would eventually consider the theory to be solidly established as one of the principles of psychology—and soon the theory would appear in psychology textbooks like the one you have been reading!
Practice: The Sequence of Events
Roll over each step to see a brief description of that phase of research.
observe an interesting behavior
form initial theory
construct hypothesis from the theory
test hypothesis by manipulating independent variable(s) and measuring dependent variable(s)
if results don’t support hypothesis → revise theory → construct hypothesis, etc.
if results support hypothesis → try to replicate results
if results can be replicated → theory is established
if results cannot be replicated → theory is rejected
form new theory — construct hypothesis, etc.
Quiz
Drag each step to its proper location in this flowchart. Then select the CHECK ANSWER button.