Research Methodology in Psychology

Study Notes

PSYC 200 focuses on psychology as a biological science, while PSYC 201 examines psychology as a social science.
Experimental designs in research can involve one plant, a single group of plants, or two different groups of plants to test variables such as fertilizer effects on growth.

Plant growth can be operationally measured through various metrics:
- Increase in height
- Number of leaves
- Size and number of fruits
- Time to reach a specific size

Single Plant Design:
- Utilize one tomato plant
- Measure average leaf size before and after applying fertilizer
- Analyze changes in average leaf size to conclude effects
Single Group Repeated-Measures Design:
- One group of tomato plants
- Measure average leaf size before and after fertilization
- Compare leaf size changes over time
Two-Random-Samples Design:
- Group A: No fertilizer
- Group B: Fertilizer applied
- Compare average leaf sizes between the two groups after 10 days
Two-Groups & Repeated Measures:
- One random sample for each group measuring average leaf size before treatment
- Apply treatment and measure average leaf size afterward
- Analyze changes to determine fertilizer effects between groups

Selecting an experimental design depends on the research question and the feasibility of the study.
Each design has advantages and disadvantages in terms of control, clarity, and data comparability.

Three primary goals:
- Description of phenomena
- Explanation of findings
- Prediction of future behaviors or outcomes

Essential for qualitative concepts to make them measurable quantitatively.
Examples from other sciences:
- Physics defines velocity as Distance/Time.
- Density as Mass/Volume.
In psychology:
- Short-term memory capacity measured by the number of chunks recalled.
- IQ calculated using (Mental Age/Chronological Age) X 100.

Standardizes abstract concepts to ensure consistency in research communication.
Necessary for different research studies to align on the same terminology, allowing for accurate comparisons and measurements.