Research in PsychologyChapter Two

AP Psychology

Thinking Critically About Psychology

1. What am I being asked to believe or accept?

2. What evidence is available to support the assertion?

3. Are there alternative ways of interpreting the evidence?

4. What additional evidence would help to evaluate the alternatives?

5. What conclusions are most reasonable?

Reliability and Validity

Evidence addressing a hypothesis should be judged in terms of reliability and validity.

Theories

• A theory is an integrated set of statements designed to account for and predict ways of controlling certain phenomena.

• They are tentative explanations that must be subjected to scientific evaluation.

• They are constantly being formulated, evaluated, reformulated, and sometimes abandoned based on research results.

Goals of Psychological Research

• To describe the phenomenon• To make accurate predictions • To demonstrate some control over the variables• To explain the phenomenon with confidence

Research Methods in Psychology

Naturalistic Observation

• Feature: The process of watching without interfering as behavior occurs in the natural environment

• Strengths: Provides descriptive data about behavior presumably uncontaminated by outside influences.

• Pitfalls: Observer bias and participant self-consciousness can distort results

Case Studies• Feature: Intensive examination of the behavior and mental

processes associated with a specific person, group or situation.

• Strengths: Provide detailed descriptive analysis of new, complex, or rare phenomenon.

• Pitfalls: May not provide representative picture of phenomena.

Surveys• Feature: Standard set of

questions asked of a large number of participants – asks people about their behavior, attitudes, beliefs, and opinions

• Strengths: Gather large amounts of descriptive data relatively quickly and inexpensively.

• Pitfalls: Sampling errors, poorly phrased questions, and response biases can distort results.

Correlational Studies

• Feature: Examine the relationships between research variables.

• Strengths: Can test predictions, evaluate theories, and suggest new hypotheses.

• Pitfalls: Cannot infer causal relationships between variables.

Correlation

• Correlation – the degree to which one variable is related to another

Correlation Coefficients

• Correlation Coefficient – a statistic, r, that summarizes the strength and direction of a relationship between two variables

Correlation coefficient

Indicates directionof relationship

(positive or negative)

Indicates strengthof relationship(0.00 to 1.00)

r = +.37

Strong Correlation .6-1.0Moderate Correlation .25-.6Weak Correlation 0-.25

Illusory Correlation

• The perception of a relationship where none exists

• Misinterpretation of random sequences

Experiments

• Feature: Manipulation of an independent variable and measurement of its effects on a dependent variable.

• Strengths: Can establish a cause-effect relationship between independent and dependent variables.

• Pitfalls: Confounding variables may prevent valid conclusions.

Key Terms

• Hypothesis• Independent Variable• Dependent Variable• Operational Definition• Experimental Group• Control Group

• Confounding Variables

• Random Variables• Participant

Expectations• Placebo• Confirmation Bias

Figure 2.1: A Simple Two-Group Experiment

Independent Variable: Whether or not one received the EMDR treatment.Dependent Variable: Anxiety level.

Sources for Confounding Variables

• Random Variables– Importance of random assignment

• Participants’ Expectations– Placebo effect

• Experimenter Bias– Often minimized through the use of a

double-blind design

Research

• Basic research- describe and understand behavior without immediate concern for practical use.

• Applied research- scientific studies to solve problems of everyday life.

Selecting Human Participants for Research

• The sampling procedures used can:– Affect the research

results.– Limit the meaning of

the results

• Sampling – the process of selecting participants for research

Representative Samples• A group of research participants whose

characteristics fairly reflect the characteristics of the population from which they were selected

• If psychologists want to make scientific statements about the behavior and mental processes of any large group, they must use a representative sample of participants

Random vs. Biased Samples• Random - A group of research

participants selected from a population whose members all had an equal chance of being chosen

• Biased – A group of research participants selected who did not have an equal chance of being chosen

Convenience Samples

• Populations that are conveniently available to the researcher

• Researcher must check age, gender, ethnicity, and other characteristics of participants

Statistical Analysis of Research Results

• Descriptive Statistics - #s that describe a set of research data– Measures of Central Tendency– Measures of Variability– Correlation Coefficients

• Inferential Statistics – a set of mathematical procedures that help researchers infer what their data mean

Cross-Sectional Research• A study of various ages at one point in

time.

• Positives: can gather information about the effect in each age group

Ethics

• Ethical considerations:– Reviewed by a board in academic institutions– Codes put out by APA

• Obtain informed consent from all subjects• Protect subjects from harm and discomfort• Treat all data confidentially• Explain the experiment and results to subjects

afterward.

Animal Care

• Reviewed by a committee IACUC (institutional animal care and use committee)

• Will periodically visit animal colonies to ensure proper care

• http://www.apa.org/science/leadership/care/care-animal-guidelines.pdf

Measures of Central Tendency

• Mean – average

• Median – halfway point

• Mode – occurs most frequently

Measures of Variability

• Range – difference between highest and lowest values

• Standard Deviation (SD) – average distance between each score and the mean of the data set

Table 2.4: A Set of Pretreatment Anxiety Ratings

Citations

• Psychology, Seventh Edition http://college.cengage.com/psychology/bernstein/psychology/7e/instructors/protected/ppts.html

• http://www.lbusd.k12.ca.us/millikan/Teacher_folder/HawkinsS/AdPlPsychology2.htm