research methods. goals of psychology describe explain predict control …………behavior and...

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.