During a pivotal scene in the television series Twin Peaks, a FBI agent is led into a strangely lit room, where a dwarf speaking a bizarre form of reversed English reveals the name of a woman's killer. Immediately, the agent bolts upright in a hotel bed, obviously shaken by the vision. This blend of fantasy and reality is known as a dream sequence, and is commonly used in film and television productions to suggest a character's inner thoughts, or a subconscious exploration of real life scenarios. The audience may be fully aware of the scene's dreamlike qualities, or else be tricked into believing the events were real.
Many times a dream sequence is filmed differently than the rest of the movie or television show. Special lenses or lighting techniques could give the scene a softer focus or an ethereal, otherworldly feel. The entire scene may be shot from the dreamer's point of view, possibly with a distorting fish eye lens. Familiar characters may act in completely unfamiliar ways, adding to the dreamer's disorientation. In essence, a well-crafted dream sequence attempts to recreate the same sense of disconnected reality as real dreams do.
A leading character in a romantic comedy, for example, may dream of proposing to the woman of his dreams, only to be humiliated when another man comes to the door. The shock is often enough to jar the character awake, revealing it was all a dream sequence. The real proposal scene may mirror the dream, but the other man turns out to be her brother. The alternative dream sequence helps to set the audience up for a much more positive outcome. Without it, the audience would have no sense of the character's underlying doubts and concerns.
A film's dream sequences may also foreshadow real life events, as seen in the film Apollo 13. Astronaut Jim Lovell has an extended dream sequence in which the spaceship suffers a catastrophic failure, leading to the deaths of all three crewmen. Later in the film, the real Apollo 13 mission does experience a major disaster, although the outcome is far less grim. The dream sequence introduces a sense of impending danger to the audience, as well as revealing Lovell's innermost concerns about the safety of the mission.
Sometimes a dream sequence is edited in such a way that the audience is shocked to see it end so abruptly. Other times the acting is so deliberately over-the-top that audience members never forget they are watching a dream sequence. One entire season of the television series Dallas actually became an extended dream sequence after actor Patrick Duffy reprised his role as Bobby Ewing. In order to explain his absence from the show, the writers wrote a new scene which revealed his wife Pam had only dreamed the events of that season.
An effective dream sequence can add foreshadowing, comic relief or dramatic tension to a movie or television series, as long as the audience is provided enough information to separate the fantasy from the reality. Television shows such as Medium, in which a character receives clues through psychic dreams, usually handle this type of dramatic device very well.