Psychology Research Methods: Structured Study Notes

Psychology Research

The Scientific Method in Psychology

The scientific method is a systematic approach used in psychology to investigate phenomena, acquire new knowledge, or correct and integrate previous knowledge. It relies on empirical evidence and logical reasoning.

• Theory: An organized system of assumptions and principles that attempts to explain a set of phenomena.

• Steps in Scientific Research:

  1. Identify a problem or question

  2. Create a hypothesis: A statement that attempts to predict phenomena, specifying relationships among variables that can be empirically tested.

  3. Design and conduct a study

  4. Analyze and interpret data

  5. Publish findings in peer-reviewed journals

• Data: Observations from a study, usually in numerical form.

Variables in Psychological Research

Variables are constructs of interest that can differ from person to person or situation to situation.

• Independent Variable (IV): A variable believed to influence or change another variable. The hypothesis manipulates the IV.

• Dependent Variable (DV): A variable that is measured to determine how it is influenced by the IV.

Example: In a study on sleep and memory, the amount of sleep is the IV, and memory test scores are the DV.

Operational Definitions

Operational definitions specify how variables are measured or manipulated in a study, ensuring clarity and replicability.

• Developmental Psychologist: May define attachment as a behavioral system evolved to promote survival and proximity to caregivers.

• Social Psychologist: May define attachment as an affective bond between two people.

Research Samples

Samples are groups of individuals selected from the population to participate in research studies.

• Representative Sample: A group of individuals that reflects important characteristics of the population.

• Convenience Sample: A sample where participants are selected based on availability and willingness.

• Random Sample: Every member of the population has an equal chance of being selected.

Intro to Research Methods

Psychological research uses various methods to collect and analyze data.

• Case Studies

• Observational Studies: Naturalistic and Laboratory

• Psychometric Assessment: Surveys, Interviews, Tests

• Experiments

Developmental Designs

• Longitudinal Design: Studies the same individuals over time.

• Cross-Sectional Design: Studies multiple age groups at one time.

Case Studies

Case studies involve in-depth examination of an individual or small group, often used to explore rare phenomena.

• Advantages: High level of detail, practical for rare cases.

• Limitations: Information can be incomplete, not generalizable.

Observational Studies

• Naturalistic Observation: Observing behavior in its natural environment.

• Laboratory Observation: Observing behavior in a controlled setting.

Experimental Assessments

• Surveys/Questionnaires: Efficient for collecting data from large groups.

• Interviews: Useful for gathering in-depth information.

• Psychological Tests: Standardized measures of cognitive skills, personality traits, etc.

Reliability and Validity

• Reliability: Consistency of assessment results across time and place. $\text{Reliability} = \frac{\text{True Score}}{\text{Observed Score}}$

• Validity: Degree to which an assessment measures what it intends to measure.

Experiments

• Experimental Group: Receives the independent variable.

• Control Group: Does not receive the independent variable.

• Random Assignment: Increases equivalency between groups.

• Single-Blind: Participant is unaware of group assignment.

• Double-Blind: Both participant and researcher are unaware of group assignment.

Validity: Experimental Design

• Internal Validity: How well the study controls potential confounding factors.

• External Validity: Extent to which findings can be generalized to other settings.

Developmental Designs

• Longitudinal Design: Studies individuals over time, useful for examining development.

• Cross-Sectional Design: Studies multiple groups at one time, useful for comparing differences.

Design	Advantages	Limitations
Longitudinal	Examines changes over time	Time-consuming, costly
Cross-Sectional	Quick, cost-effective	Cannot establish temporal relationships

Evaluating Research Findings

Descriptive Statistics

• Measures of Central Tendency: Mean, Median, Mode

• Measures of Variability: Range, Standard Deviation

Measure	Definition	Calculation
Mean	Average value	Add all values, divide by number of values
Median	Middle value	Order values, find center
Mode	Most frequent value	Count occurrences

Measures of Variability

Measure	Definition
Range	Difference between highest and lowest values
Standard Deviation	Average distance each value is from the mean

Correlations

• Correlation Coefficient (r): Measures direction and strength of relationship between variables. $-1 \leq r \leq 1$

• Positive Correlation: Variables move in same direction.

• Negative Correlation: Variables move in opposite directions.

• Third-Variable Problem: An unmeasured variable may influence both variables being studied.

Inferential Statistics

• Statistical Significance: Probability that results are not due to chance. P-value: $p < 0.05$ is typically considered statistically significant.

APA Formatting - References

• In-Text Citation: (Author, Year) or Author (Year)

• End-of-Text Reference: Author, Initials. (Year). Title. Source.

Example: Smith & Harris (2009) found that culture influences self-esteem.

Additional info: These notes cover the essentials of psychological research methods, including the scientific method, variables, sampling, research designs, statistics, and APA formatting, suitable for exam preparation in a college psychology course.