One of the most important challenges for producers of television shows and motion pictures is to keep the audience interested from the very first minutes of the broadcast. This is often accomplished through the use of a dramatic device known as a cold open, sometimes called a teaser. A cold open is a snippet of action shown before the actual rolling of a show or movie's opening credits. Sometimes a cold open is a quick reprise of previous plotlines, or it may be an attention-grabbing cliffhanger which hooks the viewer into the rest of the show.

Soap operas often use a cold open to bring viewers up to speed on the plotlines the new episode will explore. A crime show might show details of the actual crime as a cold open, then run the opening credits several minutes later. Action/adventure movies such as the James Bond spy series often employ a cold open of the hero making a dramatic escape from enemies who may or may not have anything to do with the actual plot. The point of a cold open is to discourage viewers from changing the channel during the opening credits or to set the pace for the rest of the film.

Some television shows do not use a cold open, such as most late night talk shows. The opening credits run precisely at the beginning and an announcer or graphics introduce the guest line-up. However, a sketch comedy show such as Saturday Night Live will use a cold open, typically a short skit based on a current event. The actual credits do not run until a character has delivered a catchphrase or excitement-generating stunt.

The use of a cold open can be traced back to at least the 1960s, as network producers noticed that viewers were often switching channels during the opening credits of familiar shows without waiting for the first scene. To counteract this habit, many shows were restructured to include a cold open or teaser sequence. During a sitcom's cold open, for example, the main characters might be shown receiving a mysterious package and showing shock at the unseen contents. This cold open would hook curious viewers who wanted to know what was in that box and what might happen next.

A cold open for a drama might show the end of an episode with a voice-over explaining how the characters wound up in their predicament. Curious viewers would naturally want to see the beginning of the story once they have become hooked on the teaser ending. A cold open might also end on a curious or cryptic piece of dialogue, which would naturally induce curiosity in many viewers. A good cold open is all about making sure the audience wants to return to the show after the first commercial break or opening credits.

The next time you watch your favorite sitcom, crime drama or science fiction series, you may notice how the producers used a cold open to grab your attention.