Final answer:
The ability to identify the word PARK but not the single letter P when both are flashed on a screen for a very brief moment is an example of subliminal perception.
Step-by-step explanation:
When an experimenter flashes the letter P on the screen for a split second and you cannot identify it, but you can identify the word PARK when flashed for the same duration, this is an example of subliminal perception. Subliminal perception occurs when a stimulus is below the threshold for conscious awareness; your sensory receptors perceive it, but it doesn't reach conscious perception. On the other hand, when the entire word PARK is flashed, it likely provides enough context for your brain to recognize it as a meaningful pattern, thus allowing you to perceive it despite the short duration.