Final answer:
Sleep research often utilizes an Electroencephalogram (EEG) to record brain waves due to its ability to measure the brain's electrical activity with high time accuracy.
Step-by-step explanation:
In sleep research, when participants' brain waves are recorded, this typically involves the use of an Electroencephalogram (EEG). The use of EEG is ideal for this type of research because it provides a measure of the brain's electrical activity. The electrodes placed around a participant's head capture the electrical activity and produce a printout of brainwaves, detailing both the frequency and amplitude with great time accuracy. This makes EEG particularly useful for studying sleep patterns and identifying various sleep stages, which present distinct patterns in brain wave activity.
Other techniques like Positron Emission Tomography (PET), Magnetic Resonance Imaging (MRI), and Computerized Axial Tomography (CAT scan) also provide valuable insights into brain function, but they do not possess the same temporal precision as EEG when it comes to monitoring dynamic processes such as sleep stages.