1. Research Methods
Unit 2 (Chapter 2)

2. The Scientific Approach
Empiricism
Basic assumption: events are governed by some lawful order
Goals:
Measurement and description
Understanding and prediction
Application and control
Goal of theory testing in science: refutation not proving
Psychologists assume that behavior is governed by discernible laws or principles; these just need to be uncovered.
The goals of the scientific enterprise of psychology are:
To measure and describe a phenomenon, for example sociability.
To understand and predict…psychologists form hypotheses about how variables interact. A hypothesis is a tentative statement about the relationship between 2 or more variables. Variables are the things that are observed or controlled in a study.
To apply and control…information gathered by scientists may be of some practical value in helping to solve problems in schools, businesses, mental health centers, etc.

3. Steps of the Scientific Method
1. Developing a Hypothesis:
-Hypothesis: A statement predicting the outcome of a scientific study or describing the relationship among variables in a study.

4. Steps of the Scientific Method
2. Design test: A hypothesis must undergo rigorous tests before it will be accepted as a legitimate theory.
To make a test controlled, one must account for the independent variable.
Independent Variable: A stimulus condition that the experimenter changes independently of all other carefully controlled conditions in the experiment.

5. Steps of the Scientific Method
3. Collect data: getting information by direct observation that relies only on the independent variable and not on the experimenter’s hopes. This data is called the dependent variable.
Dependent Variable: The measured outcome of a study, or the response of the subjects in the study.

6. Steps of the Scientific Method
4. Analyzing the results: This step consists of looking at the data collected and seeing if it supports or disproves the hypothesis.

7. Steps of the Scientific Method
5. Publishing, criticizing and replicating the results: The last step of the scientific method is to have the results withstand the criticism and scrutiny of the science community.
Replicate: To do a study over to see if the same results are obtained. To control for bias, the replication is most often done by someone other than the original researcher.

8. The Scientific Method: Terminology
Operational definitions are used to clarify precisely what is meant by each variable
Participants or subjects are the organisms whose behavior is systematically observed in a study
Data collection techniques allow for empirical observation and measurement
Psychologists use operational definitions to clarify what their variables mean…what exactly is sociability?
Researchers use procedures for making empirical observations and measurements, including direct observation, questionnaires, interviews, psychological tests, physiological recordings, and examination of archival records.
They depend on statistics to analyze data and decide whether hypotheses were supported…observations are converted into numbers, which are then compared.
They share their findings through reports at scientific meetings and in scientific journals…this way others can evaluate new research findings and build new ideas.
Using the scientific approach, scientists state EXACTLY what they are talking about, resulting in clarity of communication. The scientific method also yields more accurate and dependable information than, for example, speculation.
Research methods consist of differing approaches to the observation, measurement, manipulation, and control of variables in empirical studies.

9. The Scientific Method: Terminology
Statistics are used to analyze data and decide whether hypotheses were supported
Findings are shared through reports at scientific meetings and in scientific journals – periodicals that publish technical and scholarly material
Advantages of the scientific method: clarity of communication and relative intolerance of error
Research methods: general strategies for conducting scientific studies
Psychologists use operational definitions to clarify what their variables mean…what exactly is sociability?
Researchers use procedures for making empirical observations and measurements, including direct observation, questionnaires, interviews, psychological tests, physiological recordings, and examination of archival records.
They depend on statistics to analyze data and decide whether hypotheses were supported…observations are converted into numbers, which are then compared.
They share their findings through reports at scientific meetings and in scientific journals…this way others can evaluate new research findings and build new ideas.
Using the scientific approach, scientists state EXACTLY what they are talking about, resulting in clarity of communication. The scientific method also yields more accurate and dependable information than, for example, speculation.
Research methods consist of differing approaches to the observation, measurement, manipulation, and control of variables in empirical studies.

10. Experimental Research: Looking for Causes
Experiment = manipulation of one variable under controlled conditions so that resulting changes in another variable can be observed
Detection of cause-and-effect relationships
Independent variable (IV) = variable manipulated
Dependent variable (DV) = variable affected by manipulation
How does X affect Y?
X= Independent Variable, and Y= Dependent Variable
An experiment is a research method where there is manipulation of one variable under carefully controlled conditions so that resulting changes in another variable can be observed…key word “resulting.”
Experiments are very powerful in that they allow for detection of cause-and effect relationships…Does X cause Y?
The IV is the variable that the experimenter controls or manipulates…the DV is the variable thought to DEPEND (at least in part) on manipulation of the IV.
If we wanted to know how X affects Y, X would be the IV, and Y would be the DV.

11. Experimental and Control Groups
Experimental group – subjects who receive some special treatment in regard to the independent variable
Control group – similar subjects who do not receive the special treatment
Logic:
Two groups alike in all respects (random assignment)
Manipulate independent variable for one group only
Resulting differences in the two groups must be due to the independent variable
Extraneous and confounding variables
In an experiment, the investigator assembles two groups who are as alike as possible, an experimental group (who receives a special treatment in regard to the independent variable) and a control group (who do not receive the special treatment). Then, after they administer the treatment, if the two groups differ on the dependent variable, it MUST be due to the treatment.
An extraneous variable is a variable, other than the independent variable, that may influence the dependent variable.
Confounding of variables occurs when participants in one group of subjects are inadvertently different in some way from participants in the other group, influencing outcome.
Random assignment of subjects is used to control for confounding variables.

12. Experimental Designs: Variations
Expose a single group to two different conditions
Reduces extraneous variables
Manipulate more than one independent variable
Allows for study of interactions between variables
Use more than one dependent variable
Obtains a more complete picture of effect of the independent variable
Experimental designs can be quite complex. These are a few of the ways designs can vary.
Sometimes, a single group can be used for both experimental and control conditions…for example, you might study the effects of having the radio on when people work on an assembly line…you’d collect data from the same group of workers twice, once with the radio on and once with it off.
Researchers can also manipulate more than one IV to see what the combined effect is…sometimes, the effect of one variable depends on the effect of another…for example, you might find that having the radio on increases productivity in workers, but only in the morning…in this example, time of day interacts with the effects of the radio.
Researchers can also use more than one dependent variable in a single study to get a more complete picture of the effect of the independent variable. For example, we might measure not only number of pieces workers finish when the radio is allowed to be on while they work, but also worker satisfaction, absenteeism, and attitude. Having 1 day less a month absenteeism might make up for a slight decrease in productivity.

13. Descriptive Research Methods
Strategies for observing and describing behavior
Typically words instead of numbers (qualitative)
Do not manipulate anything in the research

14. Observations Observe behavior by watching and recording information
Naturalistic – in the natural setting, creates a purer result
Lab – more controlled, but less natural

15. Case Studies One individual studied in great detail
Typically rare cases
You collect information in several ways

16. Surveys Asking questions about a specific topic Very direct
Use interviews, questionnaires, surveys

17. Statistics and Research
Statistics – using mathematics to organize, summarize, and interpret numerical data
Descriptive statistics: organizing and summarizing data
Inferential statistics: interpreting data and drawing conclusions – use of probability
Statistics - using mathematics to organize, summarize, and interpret numerical data…statistical analyses allow researchers to draw conclusions about their data.
Statistics are a part of everyday modern life…batting averages, economic projections, popularity ratings for TV shows, etc.
There are two basic types of statistics, descriptive and inferential.
Descriptive statistics are used to organize and summarize data to provide some sort of overview.
Inferential statistics use the laws of probability to allow researchers to interpret data and draw conclusions.

18. Descriptive Statistics: Measures of Central Tendency
Measures of central tendency = typical or average score in a distribution
Mean: arithmetic average of scores
Median: score falling in the exact center
Mode: most frequently occurring score
Which most accurately depicts the typical?
Measures of central tendency are used to describe the typical or average score in a distribution.
The mean is the arithmetic average and is therefore sensitive to extreme scores.
The median is the score that falls exactly in the center of the distribution.
The mode is the most frequently occurring score.
Which one is the most accurate depiction of the typical score? It depends on the data, as depicted on the next slide.

19. Descriptive Statistics: Variability
Variability = how much scores vary from each other and from the mean
Standard deviation = numerical depiction of variability
High variability in data set = high standard deviation
Low variability in data set = low standard deviation
Variability refers to how much scores in a set of data vary from one another and from the mean…the standard deviation is a numerical index of variability.
If the variability in a data set is high, the standard deviation will be a higher number than if the variability is low, as is evident in Figure 2.13.

20. Normal Distribution A normal distribution is a bell shaped curve.
A standard deviation of 1 accounts for about 68% of responses.

21. Descriptive Statistics: Correlation
When two variables are related to each other, they are correlated.
Correlation = numerical index of degree of relationship
Correlation expressed as a number between 0 and 1
Can be positive or negative
Numbers closer to 1 (+ or -) indicate stronger relationship
A correlation exists when two variables are related to each other.
The correlation coefficient is a numerical index of the strength and direction of association between two variables.
A correlation is expressed as a number between 1 and 0, and the number may be positive or negative.
The closer to 1 the number is, whether +1 or –1, the stronger the relationship between the variables…for example, a correlation of .17 is pretty weak, while a correlation of -.89 is pretty strong.
The positive/negative dimension of the correlation coefficient expresses the direction of the relationship. If two variables are positively correlated, they co-vary in the same direction…as scores on one variable go up, scores on the other variable go up too…if two variables are negatively correlated, the variables co-vary in the opposite direction…as one goes up, the other goes down.

22. Figure 2.13 Positive and negative correlation

24. Which of the following correlation coefficients presents the strongest relationship between
the variables?
a. .02
b. -.67
c. .55
d. -.14

25. Correlation: Prediction, Not Causation
Higher correlation coefficients = increased ability to predict one variable based on the other
SAT/ACT scores moderately correlated with first year college GPA
2 variables may be highly correlated, but not causally related
Foot size and vocabulary positively correlated
Do larger feet cause larger vocabularies?
The third variable problem
As a correlation increases in strength (closer to – or + 1), the ability to predict one variable based on knowledge of the other variable increases.
SAT/ACT scores are correlated with first year college GPA at a moderate .40 to this may not be perfect, but it allows admissions committees to predict with some accuracy how well a prospective student will do in college.
Although correlation may allow prediction, it does not infer cause-and-effect.
For example, a strong positive correlation has been shown between foot size in children and vocabulary…as foot size increases, so does vocabulary. Do bigger feet make children learn more words? No. It is a third variable, age, which causes both feet and vocabulary to grow.

26. Inferential Statistics: Interpreting Data and Drawing Conclusions
Hypothesis testing: do observed findings support the hypotheses?
Are findings real or due to chance?
Statistical significance = when the probability that the observed findings are due to chance is very low
Very low = less than 5 chances in 100/ .05 level
Other factors might account for the results
Researchers use inferential statistics to determine whether their data support their hypotheses…with these statistical methods, they can interpret data and draw conclusions.
Inferential statistics use the laws of probability to allow researchers to determine how likely it is that their findings are real, that is, not due to chance.
Statistical significance is said to exist when the probability that the observed findings are due to chance is very low…many psychologists see “very low” as fewer than 5 chances in 100 that results are not real…the .05 level of significance.

27. Sampling
Representative Sample: A sample obtained in such a way that it reflects the distribution of important variables in the larger population in which the researcher are interested-variables such as age, SES, ethnicity, education….

28. Evaluating Research: Methodological Pitfalls
Sampling bias
Placebo effects – is not always uniform – cost factors and perceived pain
Distortions in self-report data:
Social desirability bias
Response set
Experimenter bias
the double-blind solution
Research protocol of clinical trial for drugs – FDA in U.S.
Sampling bias – when a sample is not representative of the population…poll only men, may get a different outcome if the population is both male and female.
Placebo effects – when a participant’s expectations lead them to experience some change even though they receive empty, fake, or ineffectual treatment…cured by a sugar pill.
Distortions in self-report data:
Social desirability bias – a tendency to give socially approved answers to questions about oneself…did you vote?
Response set – a tendency to respond to questions in a particular way (agree with everything, etc.).
Experimenter bias – when a researcher’s expectations or preferences about the outcome of a study influence the results obtained…researchers see what they want to see – errors are usually in favor of the hypothesis…similarly, researchers may unintentionally influence the behavior of their subjects, possibly through body language, smiles, etc. To control for this problem, a double-blind procedure in which neither subjects nor experimenters know which subjects are in the experimental and which are in the control groups is used…a non-directly involved researcher keeps track of everything.

29. Internet Psychological Research
Internet-mediated research refers to studies in which data collection occurs over the web.
Possible Advantages
Samples that are much larger and much more diverse than the samples used in lab research
Have the potential to yield more diverse and representative samples

30. Internet Psychological Research
Potential Disadvantages
Sampling bias resulting from self-selection may be a more troublesome issue in Internet-mediated research
Web users tend to be younger, brighter, and more affluent than nonusers
Data are collected under far less controlled conditions than in traditional studies

31. Ethics in Psychological Research: Do the Ends Justify the Means?
The question of deception
The question of animal research
Controversy among psychologists and the public
Ethical standards for research: the American Psychological Association
Ensures both human and animal subjects are treated with dignity
The question of deception:
Is it OK to make subjects think they are hurting others? Have homosexual tendencies? Think they are overhearing negative comments about themselves?
The question of animal research:
Controversy regarding humane treatment of animals vs. no use of animals in research.
These and other ethical issues have led the American Psychological Association (APA) to develop a set of ethical standards for research, to ensure that both human and animal subjects are treated with dignity.

32. Ethics in Psychological Research: Do the Ends Justify the Means?
Tuskegee Syphilis Study: