Final answer:
Lightly spraying dreamers' faces with cold water makes them more likely to experience lucid dreams, as the external stimulus can make them aware that they are dreaming.
Step-by-step explanation:
When dreamers' faces are lightly sprayed with cold water, they are more likely than other dreamers to experience lucid dreams. Lucid dreaming is a phenomenon where the sleeper is aware that they are dreaming and may even be able to exert some control over their dream environment. This sensation can be triggered by external stimuli, such as a light spray of cold water. In lucid dreams, the sleeper might realize their dream state due to the mild discomfort or the unusual feeling of the water on their skin, which doesn't match the dream narrative and thus alerts the dreamer to the fact that they are dreaming.
Night terrors, on the other hand, are more severe than nightmares and involve intense fear, screaming, and even attempts to escape the immediate environment, but they are not typically induced by external stimuli like water. Sleepwalking and talking in one's sleep also involve acting out behaviors during sleep, but they are unlikely manifestations of dream content because both activities occur during non-rapid eye movement (NREM) sleep, whereas dreams and particularly vivid or memorable dreams, occur during rapid eye movement (REM) sleep. As such, the explanation that individuals are acting out their dreams during sleepwalking or talking in sleep is considered unlikely.