RM

Science in Psychology (full) - Tagged_11zon (2)

Scientific Thinking in Research Psychology

Investigating Cause and Effect

  • Overview of today's topic covering:

    • Research questions

    • Levels of measurement

    • Types of research approaches

Brief Recap of Some Concepts from PY2103

Types of Research Questions

  • Differentiate between types:

    • Descriptive: Describes population/sample

    • Correlational: Examines relationships between variables

    • Causal: Investigates cause-effect relationships

Levels of Measurement

  • Types:

    • Nominal: Categorical data (e.g., animal preference)

    • Ordinal: Order data (e.g., marathon rankings)

    • Interval: Equal differences between values (e.g., Likert scales)

    • Ratio: Contains a true zero value

Research Methodologies

  1. Experiments

    • Often yield causal claims

  2. Qualitative Research

    • Explores themes and patterns in data

  3. Quantitative Research

    • Relies on numerical data and statistical analysis

    • Includes exploratory designs (correlational, longitudinal, etc.)

Measures of Central Tendency and Dispersion

Central Tendency

  • Mean: Average score (sum of scores / number of scores)

  • Median: Middle value in ordered data

  • Mode: Most frequently occurring score

Dispersion Measures

  • Variance: Measures score spread

  • Standard Deviation: Average distance of scores from the mean

Statistical Tests

Types of Tests

  • Parametric: Assumes underlying statistical distributions

  • Non-parametric: Does not assume distribution; useful for categorical data

  • Examples include t-tests and Chi-squared tests

Research Approaches

Qualitative vs. Quantitative

Qualitative Research

  • Explores subjective experiences; more descriptive and thematic

Quantitative Research

  • Based on numerical data, statistical models, and hypotheses testing

Non-Experimental Quantitative Research

  • Correlational Studies: Measures relationships without manipulation

  • Cross-Sectional Studies: Observations at a single point in time

  • Longitudinal Studies: Observations over multiple time points

    • Cohort Studies: Focus on groups sharing a characteristic

Natural Manipulation Studies

  • Observations in natural contexts without manipulation from researchers

Experimental Research

  • Involves deliberate manipulation to observe effects

  • Randomized control trials are key type of experimental design

Key Characteristics of Experiments

  1. Objective observation of phenomena

  2. Control of variables, isolation of the independent variable (IV)

  3. Systematic measurement of outcomes (dependent variable, DV)

Investigating Cause and Effect

Essential Conditions for Causal Claims

  1. Relationship Condition: Variables must be associated

  2. Temporal Order Condition: Changes must occur in the correct order

  3. No Alternative Explanation Condition: Rule out other variable explanations

Example of Cause and Effect Study

  • Nisbett and DeCamp Wilson's (1977) study on the halo effect:

    • Variables manipulated and measured provide strong basis for causal claims

Other Research Approaches

  • Discuss weak designs prone to internal validity issues

  • Importance of random assignment to strengthen causal claims.

Strength vs. Weakness of Study Designs

  • Strengths:

    • Experimental designs support strong causal inferences

  • Weaknesses:

    • Ethical or practical limitations in manipulating certain variables

Conclusion

  • Understanding these concepts aids in evaluating psychological research and its effectiveness.