Final answer:
Measuring sleepiness by counting yawns in a one-hour period is a behavioral method. It uses observable actions to quantify a d) physiological state and is distinct from subjective or physiological measures like EEG recordings.
Step-by-step explanation:
Using the number of yawns in a one-hour period as a definition and a measurement of sleepiness is an example of behavioral sleepiness. This approach to quantify sleepiness is based on observable actions, which in this instance, is the act of yawning. From a methodological standpoint, using yawns as a measure is favored over subjective measures, which rely on personal reports and are more prone to bias. Objective recording of an action provides a means of quantifying a physiological state without requiring self-reporting, making it a behavioral marker.
Behavioral measures of sleepiness, like the frequency of yawns, differ from physiological measures, such as those that would be identified through an EEG. While behavioral measures rely on outward behaviors that presumably reflect internal states, physiological measures directly record the biological activity associated with those states.