instructor bar-navon the methods of psychology unit 2 - psychology
TRANSCRIPT
Instructor Bar-Navon
The Methods of Psychology
UNIT 2 - PSYCHOLOGY
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The Science of Observation
- Observe what people do• “John picked up an apple”
- Explain why they do it• “he is going to eat it”• “he is going to throw it at me”
- Measurement•must “define” what we wish to measure•must find a way to detect it
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The Science of Observation
- Easy to measure physical properties• like “distance”
- Not so easy to measure psychological properties• like “happiness”• “a specific set of muscular contractions?” (EMG)
- With so many ways to “measure” things, it is hard to know what is the right way
Research Methods
Goal of Research: to find the truth! What is really going on??
How can we conduct research to get at the truth?
1. Adhere to the scientific method
2. Make sure your study is falsifiable or subject to replication.
3. Propose a theory that is not overly complicated. Keep it simple whenever possible.
Research Methods
Two types of research methods:
1. Non-experimental.
- hands-off: no control
- real-world setting
2. Experimental.
- hands-on: control
- laboratory setting
Research Methods
Non-Experimental Research Methods.
1. Naturalistic observation.
- qualitative
- Jane Goodal and Chimpanzees
- Dian Fossey and Gorillas
Research Methods
Limitations:
- lengthy and time-consuming
- observer bias: AKA experimenter bias. When the researcher is biased in his/her observations – usually in the direction that supports his/her hypothesis.
- observer effect / reactivity: When people behave differently when they know they are being watched or observed.
Research Methods
2. Case study.
- A detailed description of an individual with a rare or unusual disorder
- In-depth analysis
- Can be used to describe and explain behavior
- Famous cases: patient H.M., Phineas Gage, Genie “the wild child”
- For more information on Genie’s case see: http://www.psychology.sbc.edu/cesarz.htm
Phineas Gagefor more info: http://www.deakin.edu.au/hmnbs/psychology/gagepage/
Patient H.M.
For more information on H.M., see the link below:
http://thebrain.mcgill.ca/flash/capsules/pdf_articles/patient_hm.pdf
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Case Study
-Limitations: results can not be applied to the general population
Research Methods
Research Methods
3. Surveys.
- questionnaires that allow psychologists to measure covert behaviors: attitudes, opinions, values, beliefs, etc.
- can be easily used to measure large groups of people
- more quantitative
- can be used to describe, explain, and even predict behavior
Research Methods
3. Surveys [cont’d]
- population: everyone (the entire pizza pie)
- sample: not everyone or a subset of the population( a slice of the pie)
- You want your sample to be representative of the population. Why?
- So you can generalize your results to the population. (e.g. - You don’t have to eat the entire pizza pie to see how it tastes. You can just eat one slice!)
Research Methods
3. Survey limitations
- Sample bias: when your sample is different from the population
- Example: When you happen to eat the only slice in the entire pie that is pepperoni. This is problematic if you erroneously assume that the rest of the pie is also pepperoni.
- Sample results can NOT be generalized to the population
- Random samples eliminate sample bias
- Random sample: when every element in the population has an equal chance of being selected into the sample.
- Lotto number drawings
Research methods
Survey limitations - social desirability: When people change their actual
attitudes, values, beliefs, etc. in order to please the experimenter and/or to appear politically correct. In other words, when people lie on a survey to make themselves look or feel good.
- anonymous responses – helps to eliminate this problem somewhat
Research methods
If you are interested in finding out how many hours per week the average full-time college student in the US studies, what would be your population?
Your sample?
Which study would you prefer to do? Why?
Research Methods
4. Correlational research.
- examines the relationship between two variables as they occur naturally
- hands-off
- no experimenter manipulation or control
- real world data
- heavily quantitative
- correlation coefficient (r2)
- frequently used to predict behavior
Research methods
Correlation Coefficient.
- A number with a range of -1.0 and +1.0 that expresses numerically the relationship between two variables.
- The sign of the number indicates the direction the two variables are moving in relation to each other
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Correlation Coefficient cont.
-A positive correlation means both variables are moving in the same direction (e.g. – temperature outside and # of ice cream cones consumed)
-A negative correlation means both variables are moving in opposite directions (e.g. – temperature outside and the number of layers of clothing)
Research methods
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Research Methods
- Measuring correlation• more-more/less-less• more-less/less-more
- Correlation coefficient • measure of direction & strength• r = 1• r = -1• r = 0
Research Methods
Correlation Coefficient cont.
Say you have 2 variables: height and IQ, and you want to find out if there is a relationship between these two variables. Because you can NOT control an individuals height or IQ, you decide to do correlational research.
Research Methods
- If you have a perfect +1.0 correlation, it means that for every 1” increase in height, you will see a 1 point increase in IQ.
- If you have a +.90 correlation, it means that for every 1” increase in height, you will see a +.90 increase in IQ
- If you have a +.80 correlation, it means that for every 1” increase in height, you will see a +.80 increase in IQ.
- What about a negative correlation coefficient? See if you can figure out what would happen in the above examples if the numbers were negative instead of positive?
Research methods
Correlation Coefficient (cont’d).- The number itself represents the strength of the
relationship. The closer the number is to 1.0, regardless of the sign, the stronger the relationship.
- For example, which number represents the strongest correlation coefficient?
a. -.72b. +.63c. -.56d. +.49
Research methods
Correlation Coefficient (cont’d).
- Which number represents the strongest correlation coefficient?
a. -.67b. +.63c. -.78d. +.43
Research methods
Correlation Coefficient (cont’d).
- Which number represents the weakest correlation coefficient?
a. -.67b. +.63c. -.78d. +.43
Research Methods
Experimental Research.- Typically conducted in a laboratory setting- Does not occur in the real world- Experimenter has control over outside factors
or confounds- Experimenter intentionally manipulates or
changes factors- Hands-on: experimenter manipulates and
controls variables in the study.
Research Methods
2 types of variables in experimental research:
1. Independent variable (IV): the variable that is intentionally changed or manipulated by the researcher. [the cause]
- sometimes you have different levels of the independent variable. For example, the milligram levels of a new drug.
2. Dependent variable (DV): the variable that is used to measure any change. [the effect]
Research Methods
- In experimental research, any change in the DV is seen as a direct result of the IV
- Potential confounds are controlled for
- The independent variable usually precedes or comes before the dependent variable in time.
Research Methods
Typically, there are at least two groups of subjects in experimental research:
1. Experimental group. This is the group of subjects who receives the independent variable that you are most interested in.
1. Control group. This is the group of subjects who do NOT receive any form of the independent variable.
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Research Methods
Control groups cont.
- The control group is the standard to which all other groups are compared.
- Control groups allow researchers to rule out confounds
- In a well-designed study, subjects are randomly assigned to either the experimental or control group
Research Methods
In each example, label the IV, the DV, the experimental group and the control group.
1. Researchers are interested in the effects of violent TV on aggressive behavior in children. 100 Children in 2nd grade are randomly assigned to either watch a video or read a book about Barney the dinosaur. Half read the book and ½ are shown a ½ hour video of the Power Rangers. After the videos are shown, all children are given a ½ hour of recess. Any violent or aggressive behavior is recorded.
Research Methods
2. Researchers are interested in the effects of testosterone on violent and aggressive behavior. Male rats are given injections for 1 month of the following: 10 mg of a saline solution, 10mg of testosterone, 20 mg of testosterone, or no injections at all. Any violent or aggressive behaviors were noted.
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Research Methods
Researchers are interested in the effects of a new drug on children with ADHD and their ability to pay attention in the classroom.
200 ten year old boys with ADHD were randomly assigned to one of four conditions: no drug, placebo drug, 10mg of new drug, and 10mg of ritalin .
Their ability to pay attention in the classroom was measured after the drugs were administered.
Research Methods
Researchers are interested in whether or not smoking marijuana causes an increase in appetite. 100 subjects are randomly assigned to smoke either a marijuana cigarette, or a regular nicotine cigarette.
After the subjects finish smoking, they are given a gallon of vanilla ice cream, and told that they can eat as much ice cream as they would like. The # of grams of ice cream consumed is their measure of appetite.
What is the IV in this study? The DV?
Research Methods
- Results: Subjects who smoked marijuana ate significantly more ice cream than those who smoked the regular nicotine cigarette.
- Can you conclude with confidence that smoking marijuana led to an increase in appetite?
- What other potential confounds could be at work here?
Research Methods
Potential confounds:- Lactose intolerant- Gender (Male/Female)- When the subject last ate- How much the subject likes ice cream
What if all confounds are controlled for. Can you then conclude with confidence that smoking marijuana leads to an increase in appetite?
Ethics in Research
• APS Code of Ethics
• Institutional Review Board (IRB) – a group of professionals who examine a study and make sure it is ethical before the researcher is allowed to conduct his/her experiment
Ethics in Research
• Informed consent – subjects must sign a release form indicating they are aware of any potential physical or psychological risks involved in the study.
• Informed consent is particularly important for populations that may be unduly influenced like children, prisoners, and the mentally ill.
Ethics in Research
• Deception – intentionally lying to or misleading the subject
• Debriefing – after an experiment is over, subjects are informed about the true nature of the study, and any harm that may have occurred in the experiment must be undone during debriefing.
Ethics in Research
• Freedom from Coercion
• Protection from Harm
• Risk Benefit Analysis