Using natural observational techniques is one way to examine variables of interest and gather information to understand a specific topic or area of research. However, results can vary depending on the environment or type of observation used. Specifically, when using naturalistic observation to gather data, external validity is controlled for but internal validity is very low. Therefore, it is difficult to determine if behavior changed via condition or extraneous variables. For example, a researcher wanted to examine employee production rates under various factory conditions, such as lighting and temperature. To examine changes in behavior via specific variables the researcher observed the employees under each condition (low temp. ,high temp., low light, etc.). Results suggested when the amount of lighting increased, the amount of production increased as well. However, further analysis revealed production ONLY increased DURING the observations, suggesting employees were responding to the researchers presence not the lighting or temperature. This is generally referred to as the "Hawthorne Effect"
An in-depth study of one person. In a case study, nearly every aspect of the subject’s life and history is analyzed to seek patterns and causes for behavior. The hope is that learning gained from studying one case can be generalized to many others. Unfortunately, case studies tend to be highly subjective and it is difficult to generalize results to a larger population.
Cross-sectional research is a type of research method primarily used in developmental psychology, but also utilized in many other areas including social science, education and other branches of science. This type of study examines different groups of people who differ in the variable of interest (e.g. obesity), but share other characteristics such as socioeconomic status, educational background and ethnicity.**For example, researchers studying developmental psychology may select groups of people who are remarkably similar in most area, but differ only in age. By doing this, any differences between groups can presumably be attributed to age differences rather than to other variables.**
Longitudinal research is a method used to examine relationships between specific variables and involves studying the same group of individuals over an extended period of time. **Data is first collected at the outset of the study, and may then be gathered repeatedly throughout the length of the study. In some cases, longitudinal studies can last several decades.**
Correlational studies examine relationships between specific variables. There are three possible results of a correlational study: a positive correlation, a negative correlation, and no correlation. The correlation coefficient is a measure of correlation strength and can range from –1.00 to +1.00.
* Positive Correlations: Both variables increase or decrease at the same time. A correlation coefficient close to +1.00 indicates a strong positive correlation.
* Negative Correlations: Indicates that as the amount of one variable increases, the other decreases (and vice versa). A correlation coefficient close to -1.00 indicates a strong negative correlation.
* No Correlation: Indicates no relationship between the two variables. A correlation coefficient of 0 indicates no correlation.**IMPORTANT**While correlational studies can suggest that there is a "RELATIONSHIP" between two variables, they "CANNOT PROVE" that one variable causes a change in another variable. For example, a correlational study might suggest a relationship between academic success and self-esteem exists, but it cannot show if academic success increases or decreases self-esteem. Other variables might play a role, including social relationships, cognitive abilities, personality, socio-economic status, and a myriad of other factors.
Cause-Effect (a.k.a 'simple experiment'):
A simple experiment is used to establish cause and effect, so this type of study is often used to determine the effect of a treatment. In a simple experiment, study participants are randomly assigned to one of two groups. Generally, one group is the control group and receives no treatment, while the other group is the experimental group and receives the treatment.