Why do we dream?
A dream can be defined as “a psychic production occurring during sleep and which can be partially remembered”. This form of hallucination takes place during specific stages of sleep, mainly during REM sleep, and lasts for an average of 1 hour and 40 minutes. Several hypotheses have been proposed to explain its function: dreams could confront us with emotions experienced in our daily lives for example. They could also "train" us to manage threats, because the amygdala is one of the most active brain areas during these periods, but also serve as a creativity booster, or be involved in memorization and learning.
Even if most people dream and are aware of having been in this state during the night, some people claim to have never dreamed in their lives: 1 person in 250! However, a study showed by studying people in this case that dreaming is universal, but the capacity to remember dreams would be much more variable from one person to another...
Dreaming is a phenomenon that can be observed in other species, and you have probably already caught your pet in this state. Even if we do not have the possibility to ask them directly to confirm that they have dreamed, we know that most mammals and birds present REM sleep, in variable quantities, unlike fishes and reptiles. The dream state has not yet revealed all its secrets, but it is reasonable to think that a state preserved for such a long time and across species must have a major utility...