Psychology Experiments and Designs

Types of Experiments

• Experiments can be categorized as lab, field, or natural/quasi.
• In lab experiments, the independent variable (IV) is manipulated in a controlled setting.
• Field experiments take place in a more natural environment, less controlled than labs.
• Natural/quasi experiments involve an IV that is pre-existing, for example gender, age.

Experimental Designs

• Independent groups designs involves different groups of participants experiencing different levels of the IV.
• Repeated measures involves participants experiencing all levels of the IV.
• Matched pairs design involves matching participants based on specific characteristics before assigning them to different groups.
• Counterbalancing is used to reduce order effects in repeated measures designs.

Observation Designs

• Observation designs can be controlled or naturalistic.
• Controlled observations occur in a structured environment, where the researcher controls aspects of the situation.
• Naturalistic observations occur in a natural setting, where the researcher doesn't manipulate variables.
• Observation can be structured or unstructured.
• Structured observation uses pre-set behavioral categories.
• Unstructured observations involves recording everything.

Sampling Methods

• Random sampling involves selecting participants randomly from the population.
• Systematic sampling involves selecting participants at fixed intervals.
• Stratified sampling involves selecting participants from different subgroups in proportion to their representation in the population.
• Opportunity/volunteer sampling is a convenient but potentially biased sampling method.

Self-Report Techniques

• Self-report methods include questionnaires, interviews and open or closed questions.
• Questionnaires can have open or closed questions.
• Interviews involve direct interaction, and can be structured, semi-structured, or unstructured.

Ethical Issues

• Informed consent is essential.
• Deception should only be used if essential and participants should be debriefed after the study.
• Participants must be protected from psychological harm.
• Data confidentiality is paramount.

Quantitative vs Qualitative Data

• Quantitative data is numerical and easy to analyze, compare.
• Qualitative data is descriptive, and rich in insights.

Primary vs Secondary Data

• Primary data is collected directly and can be time-consuming.
• Secondary data is obtained from previously collected sources and can be quick but less specific.

Hypothesis Testing

• A hypothesis is a testable prediction.
• IV1 and IV2 represent different levels of the independent variable.
• Testing for relationships may involve scattergrams, bar charts or tables to understand relationships.
• Positively correlated data moves both variables in the same direction.
• Negatively correlated data moves variables in opposite directions
• bell curves illustrate distribution of data.

Role of Peer Review

• Peer review ensures scientific rigor and quality.

Study Benefits to the Economy

• Studies can examine how laws, health, businesses and healthcare affect the economy.
• Examples: loss of money due to crime, loss of revenue for a business, or lack of workers in the healthcare field.