AP Psychology - Unit 0 & Research Methods

Unit 0: Science Practices

This unit introduces psychological perspectives and research methods for gathering data on human thought and behavior. Research methods are crucial throughout the AP Psychology curriculum. The AP exam requires applying these methods to multiple-choice and free-response questions in every unit.

History of Psychology

Learning Objectives

• Understanding different psychological perspectives.

Psychological Perspectives

Contemporary psychologists analyze human thought and behavior from various perspectives, categorized into eight broad categories.

Humanist Perspective

• Key Figures: Abraham Maslow (1908-1970) and Carl Rogers (1902-1987).
• Core Belief: Emphasizes individual choice and free will, contrasting with deterministic behaviorism.
• Focus: Individuals choose behaviors guided by physiological, emotional, or spiritual needs.
• Example: An introvert limiting social contact to satisfy needs with a few close friends.
• Limitations: Humanistic theories are difficult to test scientifically.
• Application: Helpful in therapy to overcome life obstacles.

Psychodynamic Perspective

• Core Belief: The unconscious mind controls much of our thought and action.
• Focus: Examining the unconscious mind through dream analysis, word association, and psychoanalytic therapy techniques.
• Mechanism: Repressed impulses or memories in the unconscious mind.
• Example: An introvert avoiding social situations due to repressed childhood trauma.

Biopsychology (or Neuroscience) Perspective

• Core Belief: Explains human thought and behavior in terms of biological processes.
• Focus: Effects of genes, hormones, and neurotransmitters in the brain.
• Example: Extroversion caused by inherited genes affecting neurotransmitter abundance.
• Future: Potentially becoming a branch of biology.

Evolutionary (or Darwinian) Perspective

• Core Belief: Examines human thoughts and actions in terms of natural selection.
• Foundation: Based on Charles Darwin's (1809-1882) theory of natural selection.
• Focus: Traits advantageous for survival are passed down.
• Example: Extroversion provides a survival advantage by making friends and allies.
• Relationship: Similar to biopsychology.

Behavioral Perspective

• Core Belief: Explains human thought and behavior in terms of conditioning.
• Focus: Observable behaviors and responses to stimuli.
• Mechanism: Reward and punishment shaping behavior.
• Example: Extroversion developed through rewards for being outgoing and punishments for withdrawing.

Cognitive Perspective

• Core Belief: Examines human thought and behavior in terms of how we interpret, process, and remember events.
• Focus: The rules we use to view the world.
• Key Theory: Jean Piaget's (1896-1980) cognitive developmental theory.
• Example: Extroversion based on interpreting social situations as important for personal life.

Social-Cultural (or Sociocultural) Perspective

• Core Belief: Examines how thoughts and behaviors vary among cultures, emphasizing cultural influence.
• Focus: Influence of cultural norms on thinking and acting.
• Example: Extroversion explained by cultural rules about social interaction.

Biopsychosocial Perspective

• Core Belief: Human thinking and behavior result from biological, psychological, and social factors.
• View: Other perspectives are too focused on specific influences (reductionistic).
• Example: Extroversion explained by genetic tendencies, conditioning, and social pressures.

Summary

Psychologists may adopt an eclectic approach, using different perspectives based on the situation. No single perspective has all the answers. Perspectives may combine or new ones may emerge with further research.

Research Methods

Learning Objectives

• Understanding the experimental method.
• Understanding the correlational method.
• Understanding naturalistic observation.
• Understanding case studies.

Key Terms

• Hindsight bias
• Confirmation bias
• Overconfidence
• Quantitative research
• Qualitative research
• Hypothesis
• Dependent variable
• Independent variable
• Falsifiable
• Operational definitions
• Replicated
• Sample
• Population
• Representative sample
• Random sampling
• Convenience sampling
• Generalize
• Stratified sampling
• Confounding variables
• Random assignment
• Experimenter bias
• Double-blind study
• Single-blind study
• Social desirability bias
• Experimental group
• Control group
• Placebo method
• Placebo effect
• Positive correlation
• Negative correlation
• Study
• Likert scales
• Directionality problem
• Third variable
• Naturalistic observation
• Structured interview
• Case study

Overview

Psychology is a science based on research. Intuition can be misleading due to:

• Hindsight Bias: The tendency to believe, after an event has occurred, that one would have predicted it.
• Confirmation Bias: The tendency to favor information that confirms existing beliefs.
• Overconfidence: Excessive confidence in one's own knowledge or abilities.

Research methods are crucial for the AP exam.

Types of Research

• Applied Research: Solves practical problems.
  • Example: Comparing different teaching methods.
• Basic Research: Explores questions of interest without immediate real-world applications.
  • Example: Studying how people form attitudes.
• Quantitative Research: Uses numerical measures.
• Qualitative Research: Uses textual responses to find key themes.

Hypotheses and Variables

• Hypothesis: Expresses a relationship between two variables.
• Variables: Things that can vary among participants.
  • Examples: Religion, stress level, height.
• Dependent Variable: Depends on the independent variable.
• Independent Variable: Manipulated by researchers to observe its effect on the dependent variable.
  • Example Hypothesis: Watching violent TV programs increases aggression.
    • Independent Variable: Watching violent television.
    • Dependent Variable: Aggression.
• Theory: Explains a phenomenon and generates testable hypotheses.
• Falsifiable: Hypotheses must be able to be disproven by data.

Operational Definitions

Explaining how variables will be measured. For instance, what defines violent programs or aggressive behaviors?

Validity and Reliability

• Validity: Research measures what it intends to measure (accuracy).
• Reliability: Research can be replicated and is consistent.

Sampling

• Participants (or subjects): Individuals on whom research is conducted.
• Sampling: Process of selecting participants.
• Population: The group from which the sample is selected.
• Representative Sample: Sample that accurately reflects the larger population.
• Random Sampling: Every member of the population has an equal chance of being selected.
  • Increases likelihood of a representative sample.
  • Allows findings to be generalized to the larger population.
• Convenience Sampling: Collecting data from an easily accessible group.
  • Examples: Using friends, family, or colleagues.
• Random Selection: Maximizes the chance that the sample will represent the population.
• Stratified Sampling: Ensures that the sample represents the population on specific criteria.
  • Example: Representing racial groups in the same proportion as the overall population.

Experimental Method

• Laboratory Experiments: Conducted in a controlled environment.
• Field Experiments: Conducted in the real world.
• Advantage of Experiments: Can show causal relationships by manipulating the independent variable and controlling confounding variables.
• Confounding Variable: Any difference between experimental and control conditions (except the independent variable) that might affect the dependent variable.
• Random Assignment: Each participant has an equal chance of being placed into either the experimental or control group.
  • Limits the effect of participant-relevant confounding variables.
• Group Matching: Ensuring experimental and control groups are equivalent on some criterion (e.g., sex, IQ scores, age) by dividing the sample accordingly.
• Situation-Relevant Confounding Variables: Differences in the experimental situations (e.g., time of day, environment) that may affect results.

Experimenter Bias

• Unconscious tendency for researchers to treat members of the experimental and control groups differently to increase the chance of confirming the researchers' hypothesis.
• Double-Blind Study: Neither the participants nor the researcher are able to affect the outcome of the research.
• Single-Blind Study: Only the participants do not know to which group they have been assigned.
• Demand Characteristics: Cues about the purpose of the study.
• Response or Subject Bias: Tendency for participants in a study to behave in certain ways.
• Social Desirability Bias: Tendency to give answers that reflect well on oneself.

Groups in Experiments

• Experimental Group: Receives the treatment operationalized in the independent variable.
• Control Group: Does not receive the independent variable; serves as a basis for comparison.
• Hawthorne Effect: The act of selecting a group of people on whom to experiment affects the performance of that group, regardless of what is done to those individuals.
• Placebo Method: Control group receives an inert substance to separate the physiological effects of a drug from the psychological effects.
• Counterbalancing: Using participants as their own control group, alternating the order of tasks to eliminate order effects.

Correlational Method

• Expresses a relationship between two variables without ascribing cause.
• Positive Correlation: The presence of one thing predicts the presence of the other.
• Negative Correlation: The presence of one thing predicts the absence of the other.
• Ex Post Facto (Quasi-Experimental) Study: Controlling all other aspects of the research process, as in an experiment.
• Survey Method: Involves asking people to fill out surveys.
  • Likert Scales: Pose a statement and ask people to express their level of agreement/disagreement with the statement.

Limitations of Surveys

• Cannot reveal a cause-effect relationship.
• Directionality Problem: Inability to tell which of the variables came first (temporal precedence).
• Third Variable: A third variable may cause both variables being studied.

Naturalistic Observation

• Observing participants in their natural habitats without interacting with them.
• Goal is to get a realistic and rich picture of the participants' behavior.

Qualitative Methods

• Data that includes open-ended questions where participants can write in their responses.
• Structured Interview: A fixed number of questions asked in a set order.
• Case Study: A full, detailed picture of one participant or a small group of participants.

Statistics

Learning Objectives

• Understanding descriptive statistics.
• Understanding correlations.
• Understanding inferential statistics.
• Understanding APA Ethical Guidelines.

Key Terms

• Central tendency
• Mean
• Median
• Mode
• Bimodal
• Positively skewed
• Negatively skewed
• Range
• Variance
• Standard deviation
• Normal curve
• Percentiles
• Correlation
• Correlation coefficient
• Scatterplot
• Statistically significant
• Effect size
• Replication
• Meta-analysis
• Peer review
• No coercion
• Informed consent
• Deception
• Informed assent
• Confidentiality
• Risk
• Protection from harm
• Debriefing

Overview

Understanding and making inferences based on numerical data is essential.

Descriptive Statistics

Describes a set of data. Includes frequency distributions (histograms and frequency polygons) showing how many students had dogs, cats, zebras, etc.

• Y-axis (vertical): Frequency.
• X-axis (horizontal): What is being graphed (e.g., pets).

Measures of Central Tendency

Attempt to mark the center of a distribution.

• Mean: The average of all the scores in a distribution.
  • Mean = {\sum{i=1}^{n} xi \over n}
• Median: The central score in the distribution.
• Mode: The score that appears most frequently.
• Bimodal: A distribution with two scores appearing equally frequently and more frequently than any other score.

Skewness

• Positively Skewed: Contains more low scores; produced by an aberrantly high score(s).
• Negatively Skewed: Contains more high scores than low scores.

In a positively skewed distribution, the mean is higher than the median. The opposite is true in a negatively skewed distribution.

Measures of Variability

Depict the diversity of the distribution.

• Range: The distance between the highest and lowest scores.

• Variance and Standard Deviation: Relate the average distance of any score in the distribution from the mean.

  • Standard deviation is the square root of the variance.
  • Higher variance and standard deviation indicate a more spread-out distribution.

• Z-scores: Measure the distance of a score from the mean in units of standard deviation.

z = {x - \mu \over \sigma}

• Scores below the mean have negative z-scores; scores above the mean have positive z-scores.

The Normal Curve

A theoretical bell-shaped curve for which the area under the curve lying between any two z-scores has been predetermined.

• Approximately 68% of scores fall within 1 standard deviation of the mean.
• Approximately 95% of scores fall within 2 standard deviations of the mean.
• Approximately 99% of scores fall within 3 standard deviations of the mean.

Percentiles

Indicate the distance of a score from 0. A person who scores in the 90th percentile has scored better than 90% of the people who took the test.

Correlations

Measures the relationship between two variables.

• Positive Correlation: The presence of one thing predicts the presence of the other.
• Negative Correlation: The presence of one thing predicts the absence of the other.

Strength of Correlations

Computed by the correlation coefficient, ranging from -1 to +1, where -1 is a perfect negative correlation and +1 is a perfect positive correlation.

Scatterplot

Graphs pairs of values, one on the y-axis and one on the x-axis. The closer the points come to falling on a straight line, the stronger the correlation.

Inferential Statistics

Determines whether findings can be applied to the larger population from which the sample was selected.

• Sampling Error: The extent to which the sample differs from the population.
• P-value: Gives the probability that the difference between the groups is due to chance.
  • A p-value of 0.05 is the cutoff for statistically significant results (5% chance that the results occurred by chance).
  • Scientists replicate results to gather more evidence that their initial findings were not due to chance.

Statistical vs. Practical Significance

• Statistical Significance: Likelihood the result is not due to chance, indicated by a low p-value (typically p < 0.05).
• Practical Significance (Effect Size): The size or importance of the effect. Can be statistically significant findings that are too small to be meaningful.
  Methods such as t-tests, chi-square tests, and ANOVAs yield a p-value. These tests consider the magnitude of the difference found and the size of the sample.

Replication Crisis

A recent trend in which many scientific findings, including those in psychology, could not be successfully replicated, leading to the need for more caution in accepting results from single studies.

Meta-Analysis

A type of research that combines the results of many studies on the same topic to approximate an average effect.

Peer Review

Prior to publication, psychology studies undergo peer review, in which experts in the field evaluate the research and provide feedback on the methodology, results, and conclusions, to ensure high-quality publications.

APA Ethical Guidelines

Ethical considerations are a major component in research design. Any type of academic research must first propose the study to the ethics board or institutional review board (IRB) at the institution.

Animal Research

• The research must have a clear scientific purpose.
• The research must answer a specific, important scientific question.
• Animals chosen must be best suited to answer the question at hand.
• Researchers must care for and house animals in a humane way.
• Researchers must acquire animal subjects legally.
• Researchers must design experimental procedures that employ the least amount of suffering feasible.

Human Research

• No Coercion: Participation should be voluntary.
• Informed Consent: Participants must know that they are involved in research and give their consent.
• Confidentiality (or anonymity): Participants' privacy must be protected.
• Risk: Participants cannot be placed at significant mental or physical risk; they must have protection from harm.
• Debriefing: After the study, participants should be told the purpose of the study and provided with ways to contact the researchers about the results.