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RESEARCH METHODS
Goals of Psychology
• Describe
• Explain
• Predict
• Control
…………behavior and mental processes
Critical Thinking
• Thinking that does not blindly accept arguments or conclusions but questions their validity
• NOT parsimonious thinking (willingly accepting the most simple explanation).
Scientific Method
• Technique using tools such as observation, experimentation, and statistical analysis to learn about the world
• Through its use, psychology is thereby considered a science.
Steps to the Scientific Method• Form a testable question• Develop a hypothesis• Test Hypothesis - Design study to collect data
– Experimental – Descriptive
• Analyze data – Use of statistical procedures– Use of meta-analysis
• Draw a conclusion• Report results
– Publication– Replication
Things That Make Us WRONG:
Why we need the scientific method
Common Sense
• Conclusions based solely on personal experience and sensible logic
• Most of the time it is good but…
• Can lead to incorrect conclusions
What are the Odds of Each?
What are the Odds of Each?
1 in 2,598,960
What are the Odds of Each?
1 in 2,598,960 1 in 2,598,960
Did you know…
• It is nearly impossible to fold a regular sheet of paper in half more than 7 times.
• Go ahead and try!
• Mythbusters pulled it off with a piece of paper as big as an airplane hanger and a steam roller.
Science vs. Common Sense• Science helps build explanations that are
consistent and predictive as opposed to conflicting and describing the past (hindsight)
• Science is based on– knowledge of facts– developing theories – testing hypotheses– public and repeatable procedures
Bias
• Situation in which a factor unfairly influences the likelihood of a particular conclusion
• Bias should be minimized as much as possible in research
Hindsight Bias• The tendency to exaggerate one’s ability to have foreseen
how something would turn out after learning the outcome.
• The “I knew it all along” phenomenon.– Week before the 1985 Super Bowl, 81% of Dr. Brigham’s students
predicted the Miami Dolphins would win. 40% said the Dolphins would win by 10 or more points.
– A week after San Francisco 49ers decisive victory, he asked the group who picked the 49ers.
• 58% said they picked the 49ers
• NO ONE remembered saying the Dolphins would win by at least 10 points.
Overconfidence• Tendency to overestimate the accuracy of
our current knowledge
• We are more confident than we are correct.
• How many of you overestimated the number of correct answers on your True/False Quiz?
Confirmation Bias• Our tendency to search for information that
confirms our beliefs and ignore those that don’t.
• Try this card trick: http://www.caveofmagic.com/results1.htm
• This works because we only look for our chosen card confirming Simeon’s mental telepathy and ignore the fact that second set of cards is in fact, an entirely new set!
• NONE of the cards in the new set is the same as the old one so of course the card you picked is missing.
Researcher Bias
• The tendency to notice evidence which supports one particular point of view or hypothesis
Volunteer Bias• People who volunteer to participate in a survey
differ from those who do not.• Those who complete it are often willing to share,
have similar interests, have spare time (magazine surveys).
• These factors skew or slant the results.
• Eliminate this by using a random sample where everyone has equal chance of being chosen to participate.
Participant Bias• Tendency of research subjects to respond in
certain ways because they know they are being observed
• The subjects might try to behave in ways they believe the researcher wants them to behave
• Can be reduced by naturalistic observation
Eliminating Bias• “Placebo Effect” – participants react because they
THINK they are receiving treatment (sugar pill)– Mind over Matter
• “Nocebo” – If told a drug won’t work, the person will feel it doesn’t work even if it is a legitimate drug.
• Single Blind Study – participants do not know if they are getting the treatment or not
• Double Blind Study – neither the researcher or the participants know if they are getting the treatment or not
Research Strategies Fall Into 2 Categories
• Descriptive—strategies for observing and describing behavior– Observation– Surveys
• Experimental—strategies for inferring cause and effect relationships among variables
Longitudinal Study
• Researchers study the same group of individuals for many years to see how they change.
• Can be very expensive and difficult to conduct
• Risky – people may drop out• Ex: Ruby Payne studied poverty
Cross-Sectional Study
• Researchers simultaneously study a number of subjects from different age groups and then compare the results to see how they are different.
• Cheaper, easier than longitudinal studies, but group differences may be due to factors other than development. (More variables.)
Longitudinal/Cross Sectional Study
Naturalistic Observation
• Method of observation where subjects are observed in their “natural” environment
• Subjects are not aware they are being watched – researcher does not interfere
• Could use hidden cameras or two way mirrors
• Ex: People eating in a restaurant
Laboratory Observation• Not always a sterile room.
• Place where the environment can be controlled to minimize the number of variables.
• Negatives are that it may cause the subject to act differently than it normally would.
• Ex: Skinner Box, maze, fish tank
Case Study• In depth study of one individual with the hopes of
determining universal principles• Generally used to investigate rare, unusual, or extreme
conditions– Example: Phineas Gage
Negatives:• This technique is very open to bias• Difficulty of applying data from one person to
everyone
Survey Method
• Research method that relies on self-reports; uses surveys, questionnaires, interviews.
• Usually a very efficient and inexpensive method; able to get a large sample
• Can you guess some limitations of this method of research?
Survey Limitations
• Accuracy is a concern; people are not always honest.
• They fear confidentiality or want to please the researcher.
• Example: Tooth brushing survey in 1960s. If as many people actually brushed their teeth as often as they claimed to brush their teeth, 33% (?) more toothpaste would have been sold that year.
Sampling Terms• (Target) Population—large (potentially infinite)
group represented by the sample. Findings are generalized to this group.
• Sample—selected segment of the population for the study
• Stratified or Representative sample—closely parallels the target population on relevant characteristics; sample is proportional to TARGET POPULATION
• Random selection—every member of larger group has equal chance of being selected for the study sample
Random Sample
• A sample that represents the target population:– Each member of the population has an equal
chance of being included.– If a sample is not random it is said to be
biased.– Increase chances of representing population
when sample is BIG ENOUGH– How would you pick a random sample???
Generalizing the Results
• Applying the findings from the research group to other groups.
• Be cautious about generalizing when it isn’t a random or stratified sample.
• Example: Car preference differs between men, women, region, socio-economic background, and more.
Correlational Study• Correlations examine relationships between
categories of facts.• Correlation reveals relationships among facts
– e.g., more democratic parents have children who behave better
• A correlational study does NOT determine HOW the two variables are related – just that they are related
• Correlational studies are helpful in making predictions.
Correlational Study• Correlation CANNOT prove causation
– Do democratic parents produce better behaved children?– Do better behaved children encourage parents to be
democratic?
• May be an unmeasured common factor – e.g., good neighborhoods produce democratic adults and
well-behaved children
• Does NOT determine why the two variables are related--just that they are related.
Correlation & Causation
• There is a strong +.90 correlation in shoe size and IQ.
• Does this mean that a large shoe size is the cause for higher intelligence?
• What else could explain this?
•YOUR FEET GROW AS YOU GET OLDER & WISER
Positive Correlation
• As the value of one variable increases (or decreases) so does the value of the other variable.
• A perfect positive correlation is +1.0.
• The closer the correlation is to +1.0, the stronger the relationship.
Negative Correlation
• As the value of one variable increases, the value of the other variable decreases.
• A perfect negative correlation is -1.0.
• The closer the correlation is to -1.0, the stronger the relationship.
Zero Correlation
• There is no relationship whatsoever between the two variables.
Experimental Design
The Only Way to Show
Cause & Effect
Experimental Terms• Variable – part of experiment that changes• Independent Variable (IV)– controlled by
researcher. This variable causes something to happen.
• Dependent Variable (DV) – watched by the researcher to see the impact of the IV. This variable is the effect that is caused by the IV.
• Good Way to Remember the difference: An IV in your arm causes something to happen (DV)
• Confounding Variable – things that cannot be controlled that can influence the experiment
Groups
• Experimental group – receives the treatment; frequently a drug
• Control group – receives no treatment; usually receives a placebo (fake drug)
Limitations of Experiments
• Conditions in an experiment may not reflect conditions of real life.
• (Must simplify variables to get useful information.)
• Ethical considerations in creating some more “real life” situations
Research Ethics
• Confidentiality – participants are more likely to be truthful if they know their privacy is protected.
• Confidentiality can be broken if information reveals harm to another person
Ethics
• Informed consent – some studies may have long term threats or irreversible effects. – Participants must be given a choice to participate after
being informed of the study.
• Deception is allowable when benefit outweighs harm and participants receive full explanation at its conclusion
Animal Research• APA has rules for animals, too.
• Often used instead of humans when topic could not be ethically studied on a human.– Ex: Early separation studied by Harlow in 1959 with
monkeys.
• Animal experiments lead to solutions with humans – eating disorders, drug treatments
• Still controversial due to the fact that animals can be harmed in studies.
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