Which of the following studies qualifies as research involving human subjects according to federal regulations?

The scenario in which a developmental psychologist videotapes toddler interactions to manage aggression qualifies as research involving human subjects according to federal regulations due to the direct interaction and engagement with individuals identified as human subjects. In this case, the toddlers are being observed and recorded, meaning that personal data and behavior are being collected in a way that can directly relate to them as individuals. Federal regulations typically define research involving human subjects as any research in which an investigator obtains data through intervention or interaction with individuals, or identifiable private information. Since toddlers are human subjects, and the study is directly aimed at their behavior, it falls squarely within the definition of research involving human subjects.

In contrast, the other scenarios do not meet the criteria for involving human subjects. The researcher asking for patient statistics is dealing with aggregate data rather than individual information that would identify patients. Analyzing historical passenger lists for immigrants does not involve current human subjects, as the data relates to people no longer living or identifiable. Similarly, conducting a linguistic study of online comments may not involve identifiable individuals, as the comments could be anonymous, thereby not meeting the criteria for research with human subjects. This distinction is crucial in determining the ethical considerations and regulatory requirements that must be followed in research involving human participants.