Identifying Research Methods: Sleep Deprivation Experiment

In the context of psychological research, understanding the efficacy of different methodologies for deriving conclusions from data is crucial. A researcher is interested in the potential effects of sleep deprivation on cognitive performance. They decide to conduct an experiment where one group of participants only sleeps for 4 hours, while another group sleeps for a full 8 hours. The researcher measures performance on cognitive tasks immediately after the respective sleep durations.

Which research method best describes this experimental design, and how does it contribute to the generalizability of the findings?