Final answer:
Reports of ghostly visions and alien abductions may be attributed to parasomnias occurring in the first stage of sleep when hypnagogic hallucinations can happen.
Step-by-step explanation:
Many researchers believe that reports of ghostly visions and alien abductions can be explained by parasomnias during the first stage of sleep. Parasomnias are a group of sleep disorders involving unwanted, disruptive motor activity and experiences during sleep. Examples of parasomnias include sleepwalking, night terrors, and restless leg syndrome. The first stage of sleep, also known as stage 1 sleep, is a transitional phase between wakefulness and sleep during which people drift off to sleep. It's during this stage that individuals may experience hypnagogic hallucinations, which can include visions and sensations that seem very real, potentially explaining experiences such as ghost sightings or feelings of alien abductions.