The Scientific Method and Research Methods in Psychology (Lecture Notes)

Vocabulary flashcards covering key terms and concepts from the lecture notes on the scientific method, measurement, statistics, research design, and ethics.

The Scientific Method

Set of principles about the appropriate relationship between ideas using empirical evidence.

Empiricism

Belief that accurate knowledge can be acquired through observation; essential element in the scientific method.

Observation

Using one's senses to learn about the properties of an event or object; foundational method of data collection.

Anecdotal Observation

Informal observations that are often inconsistent and incomplete.

Measurement

Techniques for quantifying properties to overcome limitations of observation; includes description.

Description

Providing a detailed account of observed phenomena.

Parsimony (Occam’s Razor)

The simplest theory that explains all the evidence is the best.

Operational Definition

A specification of how to observe or measure a variable so it can be studied.

Construct Validity

The extent to which a measurement actually measures the intended construct.

Reliability

Consistency or repeatability of a measurement across time, items, or observers.

Power (in measurement)

The ability of a measurement tool to detect the property of interest.

Anger (operational example)

A negative emotion; measurable through physiological and behavioral indicators (e.g., BP, temperature, breathing rate, cues).

Operationalization

Process of turning a theoretical concept into a measurable variable.

Normal Distribution

Bell-shaped, symmetric distribution; standard normal distribution has mean 0 and SD 1.

Descriptive Statistics

Brief summaries of essential information from a data set, including central tendency and variability.

Central Tendency

Measures that describe the center of a distribution (mean, median, mode).

Mode

The most frequent value in a distribution.

Mean

The arithmetic average of a distribution.

Median

The middle value when data are ordered.

Skewness

Asymmetry in a distribution; affects interpretation of mean and median.

Range

Difference between the largest and smallest values.

Standard Deviation

Average distance of data points from the mean; a measure of variability.

Correlation

Statistical relationship that describes how two variables vary together.

Positive Correlation

As one variable increases, the other tends to increase.

Negative Correlation

As one variable increases, the other tends to decrease.

Correlation Coefficient (r)

A number between -1 and 1 indicating the direction and strength of a linear relationship.

Perfect Correlation Values

r = 1 indicates a perfect positive correlation; r = -1 indicates a perfect negative correlation; r = 0 indicates no correlation.

Causation

A cause-and-effect relationship where one variable directly affects another.

Correlation does not imply causation

A correlation may be due to third variables or coincidence; cannot establish causation from correlation alone.

Quasi-experimental Design

Studies using natural correlations without random assignment; limited ability to infer causation.

Random Sampling

Each member of the population has an equal chance of being included in the sample.

Representative Sample

A sample that mirrors the population on key characteristics.

Random Assignment

Randomly assigning participants to conditions to help equalize groups and control confounds.

Inclusion/Exclusion Criteria

Rules determining who participates in a study (e.g., age, health, etc.).

Internal Validity

The extent to which a study supports causal conclusions; often balanced against external validity.

External Validity

The extent to which findings generalize to real-world settings.

Independent Variable (IV)

The variable deliberately manipulated by the experimenter.

Dependent Variable (DV)

The variable measured to assess the effect of the IV.

Control Group

Participants not exposed to the experimental manipulation.

Experimental Group

Participants exposed to the manipulation of the IV.

Null Hypothesis

The default assumption: there is no difference between groups or conditions.

Alpha (α)

The significance level used in hypothesis testing, commonly 0.05.

P-value

Probability of obtaining the observed data if the null hypothesis is true.

Statistical Significance

When p < α, the result is unlikely under the null hypothesis.

Type I Error

False positive; concluding a difference exists when it does not.

Type II Error

False negative; failing to detect a real difference.

Demand Characteristics

Cues in an observational setting that cause participants to behave as they think is expected.

Social Desirability

Tendency to respond in a way that is viewed favorably by others.

Experimenter Bias

Researcher expectations influence data collection or interpretation.

Double-Blind

Neither participants nor researchers know which condition participants are in during the study.

Ethics in Research

Protecting participants; informed consent; beneficence; justice; IRB approval; truthful reporting; data sharing.