Identify the types of research psychologists use to study developmental processes.
*The entire population of Flint, Michigan, was exposed to lead-contaminated drinking water for about 1 year in 2014-2015. You want to study how exposure to lead impacted the intellectual development of children in the area.*
Formulate a hypothesis for your study.
Discuss the three research designs described below (cross-sectional, longitudinal, cross-sequential).
Decide which of the designs would be best for testing your hypothesis and explain why.
Developmental Psychologists use different research designs than other psychology fields, such as experimental and correlational studies. In order to examine changes over the life span, developmental psychologists must examine human behavior across different stages and time frames using the three methods outlined:
The cross-sectional method examines people of different ages at a single point in time, comparing people of different ages to see changes over the life span. This method can provide a great deal of information quickly, but it doesn’t tell us whether changes are due to development or commonalities among groups, a phenomenon known as the cohort effect. This effect can be avoided by using the longitudinal method, which studies the same people over a period of time. This method allows researchers to look at developmental changes over time, but it can require a great deal of time, money, and participant investment. The cross-sequential method blends these two by looking at groups of people of different ages over time and allowing researchers to examine developmental changes within individuals and across different age groups.
Because each human is unique, it is very difficult to isolate variables as one would be able to do in chemistry or physics. The interaction between nature (genes) and nurture (environment) causes particular issues for a researcher hoping to generalize individual differences to a larger population. In the case of Flint, Michigan, researchers might compare how the toxicity affected infants, children, and adolescents over time. They might ask if children exposed earlier in the life span suffered more detrimental effects than those exposed later.
(excerpt from Licht, Hull, & Ballantyne, 2017).
