1. How Do Psychologists Ask & Answer Questions?
Psychologists, like all scientists, use the scientific method to construct theories that organize, summarize and simplify observations.
Preview Question 3: How do theories advance psychological science?

2. For example, low self-esteem contributes to depression.
Theory
A theory is an explanation that integrates principles and organizes and predicts behavior or events.
For example, low self-esteem contributes to depression.

3. People with low self-esteem are apt to feel more depressed.
Hypothesis
A hypothesis is a testable prediction, often prompted by a theory, to enable us to accept, reject or revise the theory.
People with low self-esteem are apt to feel more depressed.

4. Research Observations
Research would require us to administer tests of self-esteem and depression. Individuals who score low on a self-esteem test and high on a depression test would confirm our hypothesis.

5. Figure 2.1 Theory construction

6. Figure 2.2 Flowchart of steps in a scientific investigation

7. Is language uniquely human?
Descriptive Research
Case Study
A technique in which one person is studied in depth to reveal underlying behavioral principles.
Preview Question 4: How do psychologists observe and describe behavior?
Susan Kuklin/ Photo Researchers
Is language uniquely human?

8. + can collect tons of information
+ suggests hypothesis for further studies
+ can ask questions
- very time consuming
- any subject may be atypical
- results may be inconclusive

9. Survey
A technique for ascertaining the self-reported attitudes, opinions or behaviors of people usually done by questioning a representative, random sample of people.

10. + tons of data
+ cheap, easy, fast
+ anonymous
- uninterested subjects
- unclear questions
- subject bias
- can’t gather further information from subjects

11. Wording can change the results of a survey.
Wording Effects
Wording can change the results of a survey.
Q: Should cigarette ads and pornography be allowed on television? (not allowed vs. forbid)

12. Survey Random Sampling
If each member of a population has an equal chance of inclusion into a sample, it is called a random sample (unbiased). If the survey sample is biased, its results are not valid.
The fastest way to know about the marble color ratio is to blindly transfer a few into a smaller jar and count them.

13. Figure 2.16 The relationship between the population and the sample

14. Naturalistic Observation
Observing and recording the behavior of animals in the wild and recording self-seating patterns in a multiracial school lunch room constitute naturalistic observation.
Courtesy of Gilda Morelli

15. + subjects will act as they usually do
+ done on your own time
+ can further investigate if necessary
- cannot interact with subjects
- time consuming
- can’t always generalize results

16. What are the limitations of descriptive research?
Summary
Case studies, surveys, and naturalistic observation describe behaviors.
What are the limitations of descriptive research?

17. Correlational Research helps us find RELATIONSHIPS!
When one trait or behavior accompanies another, we say the two correlate.
Indicates strength
of relationship
(0.00 to 1.00)
Correlation
coefficient
r = +
0.37
Preview Question 5: What are positive and negative correlations, and why do they enable prediction but not cause-effect explanation?
Correlation Coefficient is a statistical measure of the relationship between two variables.
Indicates direction
of relationship
(positive or negative)

18. Two Basic Kinds of Correlations:
Positive and Negative
Positive: the variables change in the same direction, like height and weight.
Negative : the variables change in opposite directions, like:
as class absences increase, grades tend to decrease.

19. Scatterplots
Perfect positive
correlation (+1.00)
Scatterplot is a graph comprised of points that are generated by values of two variables. The slope of the points depicts the direction, while the amount of scatter depicts the strength of the relationship.

20. Scatterplots
Perfect negative
correlation (-1.00)
No relationship (0.00)
The Scatterplot on the left shows a negative correlation, while the one on the right shows no relationship between the two variables.

21. Data showing height and temperament in people.

22. Figure 2.13 Positive and negative correlation

23. Scatterplot
The Scatterplot below shows the relationship between height and temperament in people. There is a moderate positive correlation of

24. Correlation and Causation
Correlation does not mean causation! or

25. Critical Thinking 4: Correlation Does Not Prove Causation
Confusing “What” with “Why”

26. Correlations A correlation occurs when: Correlations:
two or more variables are in a relationship where one variable gives us information about the other(s).
Correlations:
allow us to predict relationships based on statistical probability.
give us an idea of both the direction (positive or negative) and degree to which two or more variables are related.

27. EXAMPLES Mild positive corr: violence on TV and aggressive behavior
Negative corr: self-esteem and depression
Positive corr: authoritative parenting style and socially competent children
Positive corr: use of heroin and previous use of marijuana

28. Examples of Correlated RelationshipsB

29. Examples of Correlated RelationshipsB

30. Examples of Correlated RelationshipsB

31. Examples of Correlated RelationshipsB

32. Correlations
It is possible (but not common) for a correlated relationship also to be a causal relationship.
Example: Unprotected sexual intercourse is both correlated with and causal of pregnancy
But, correlations do not prove causation.
Knowing what occurs does not explain why it occurs.
We can predict likely out outcomes, but not causes.

33. Correlations The Contiguity–Causation Error
This occurs when we assume that because two events happen next to each other in time, that they are in a cause-and-effect relationship.
Example:
Your mother calls, your spouse leaves the room. Therefore, your spouse left the room because your mother called.
(While this may be true, there are numerous reasons why someone would leave a room at a particular moment, other than your mother calling.)

34. The Experimental Method: Discovering the Causes of Behavior
Key Concepts
Experiment: A controlled situation in which the researcher manipulates one variable to discover its effect on another variable, while holding all other conditions constant.

35. The Experimental Method: Discovering the Causes of Behavior
Key Concepts
Independent Variable: The variable that the researcher “manipulates”.
“Manipulates” basically means that we assign different levels of the variable to different groups. For example:
Suppose the independent variable is the amount of time students have to take a test.
We can give one class 40 minutes and another 60 minutes. These are the levels of the time variable.

36. Confounding Variables…
Any variable not controlled for that could change the results of the experiment…

37. The Experimental Method: Discovering the Causes of Behavior
Key Concepts
Dependent Variable: This is an aspect of the participant’s behavior that the researcher records to see if it will be influenced by the independent variable. For example:
In the test-taking situation, we could record how many questions each student got right. Number of correct answers would be the dependent variable.
In everyday terms:
Independent Variable = “Cause”
Dependent Variable = “Effect”

38. The Experimental Method: Discovering the Causes of Behavior
Key Concepts
So if the students who get 60 minutes to take the test do better than those who get 40 minutes, we can say it was the time factor that caused this difference in performance, assuming…
there were no other differences between the classes.
Everything else must be “HELD CONSTANT”.

39. The Experimental Method: Discovering the Causes of Behavior
Additional Terms
Experimental Group: This is a group that is exposed to the independent variable.
Control Group: This is a group that is not exposed to the independent variable.
Control
Experimental1
Experimental2
Levels: 1 2

40. Experimental vs. Control Groups
The effects of violent video game play on reaction time…IV? DV? Which group plays the violent game???

41. Figure 2.6 The basic elements of an experiment

42. Double-blind Procedure
Evaluating Therapies
Double-blind Procedure
In evaluating drug therapies, patients and experimenter’s assistants should remain unaware of which patients had the real treatment and which patients had the placebo treatment.

43. Evaluating Therapies Random Assignment
Assigning participants to experimental (breast-fed) and control (formula-fed) conditions by random assignment minimizes pre-existing differences between the two groups.

44. 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.

45. Figure 2.17 Ethics in research

46. Comparison of Research Types…
Below is a comparison of different research methods.

47. Statistical Reasoning in Everyday Life
Doubt big, round, undocumented numbers as they can be misleading and before long, become public misinformation.
Apply simple statistical reasoning in everyday life to think smarter!

48. Experiment 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
Statistics are used to analyze data and decide whether hypotheses were supported
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.

49. Describing Data
A meaningful description of data is important in research. Misrepresentation may lead to incorrect conclusions.
Preview Question 8: How can we describe data with measures of central tendency and variation?

50. Measures of Central Tendency
Mode: The most frequently occurring score in a distribution.
Mean: The arithmetic average of scores in a distribution obtained by adding the scores and then dividing by the number of scores that were added together.
Median: The middle score in a rank-ordered distribution.

51. Measures of Central Tendency
A Skewed Distribution

52. Measures of Variation
Range: The difference between the highest and lowest scores in a distribution.
Standard Deviation: A computed measure of how much scores vary around the mean.

53. Standard Deviation

54. What is the difference between these data sets?

55. Normal Curve
A symmetrical, bell-shaped curve that describes the distribution of many types of data (normal distribution). Most scores fall near the mean.

56. Are these NORMAL distributions?
No, the top is positively skewed, the bottom is negatively skewed.

57. Making Inferences
A statistical statement of how frequently an obtained result occurred by experimental manipulation or by chance.

58. When is an Observed Difference Reliable?
Making Inferences
When is an Observed Difference Reliable?
Representative samples are better than biased samples.
Less-variable observations are more reliable than more variable ones.
More cases are better than fewer cases.
Preview Question 9: What principles can guide our making generalizations from samples and deciding whether differences are significant?

59. When is a Difference Significant?
Making Inferences
When is a Difference Significant?
When sample averages are reliable and the difference between them is relatively large, we say the difference has statistical significance. It is probably not due to chance variation.
For psychologists this difference is measured through alpha level set at 5 percent.