Final answer:
Subliminal perception refers to the influence of a stimulus that is too weak to be consciously perceived. It is different from sensory adaptation, which involves decreased sensitivity to a constant stimulus over time.
Step-by-step explanation:
When a person is influenced by a stimulus too weak to be perceived, this phenomenon is known as subliminal perception. Subliminal messages are below the absolute threshold for conscious awareness, meaning they are received by our sensory systems but not consciously registered. On the contrary, sensory adaptation refers to the decreased sensitivity to an unchanging stimulus over time, indicating a distinction between this process and the subliminal perception. A neutral stimulus is initially a stimulus that does not elicit a response, different from a stimulus that is processed but not consciously perceived, as with subliminal messages.