Final answer:
The study on facial recognition showing the faces of adults from various groups was experimental in nature. Longitudinal research follows participants over time, and ethical considerations are paramount in experimental studies involving human subjects, as shown in past research like the Stanford prison experiment.
Step-by-step explanation:
The most accurate statement regarding the study on facial recognition by showing participants faces of adults from various groups (i.e., African, Asian, and European descent) is that it was experimental. This type of study typically involves manipulating an independent variable to determine its effect on a dependent variable, such as the recognition of faces from different ethnic groups. An example of an experimental study in social psychology is the study of Frances Heussenstamm, a sociology professor at California State University at Los Angeles, who conducted an experiment to test her theory about police prejudice.
To address the research concerns in question, longitudinal research involves following a group of research participants for an extended period of time, allowing the study of developments and changes in the subjects. It is different from cross-sectional research, which looks at different groups at one point in time, and naturalistic observation, which observes subjects in their natural environment without manipulation.
Ethical considerations are a vital aspect of conducting research, particularly in experimental studies involving human subjects. Notable examples of unethical research include the Stanford prison experiment, which ended early due to the negative outcome and treatment of participants, and had post-experiment revelations that questioned the study's validity.