In the world of pop movie culture, the dramatic device known as the "slow clap" is in a category unto itself. Mostly seen at the end of a dramatic or inspirational movie intended for general audiences, it usually follows a climactic speech delivered by the hero or heroine. The initial effect of that speech may be stunned silence from the audience, but then one character will begin clapping rhythmically and slowly. As others begin to realize the true significance of the hero's speech, they also join in. Eventually the entire audience bursts out with exuberant, and seemingly unending, applause. There may be several meaningful close-ups of characters who have been most affected by the hero's actions.
In many critics' opinions, the "slow clap" device has been used so often in teen-oriented movies that it has become a cliche, along with the "ugly duckling/beautiful swan" subplot and the "freeze frame" ending. In fact, it has been parodied in films such as Not Another Teen Movie. It is not unusual to see certain movies such as Lucas and Revenge of the Nerds referred to as classic "slow clap movies" by amateur film critics and fans.
This device does serve a number of purposes for the dramatic arc of the story and the director's need for a strong, inspirational ending. Many "slow clap movies" feature leading characters who are underdogs or unpopular at the beginning of the movie, but they often possess a level of integrity or hidden talent unnoticed by others. There is usually a strong antagonist who does any number of things to keep the hero from discovering his or her true potential. The final speech is designed to put the hero in the best light possible, while pointing up the antagonist's fatal error in judgment. It is not unusual to see the hero's former enemy take part in the climactic slow clap.
There is another form of slow clap often found in action/adventure and crime movies. The lead character, often a detective or secret agent, will reveal all of the intricate details of a criminal's plan, only to discover the criminal has been listening all along. The villain often reveals himself by clapping slowly, usually heavy with sarcasm. The villain might congratulate the hapless hero for his or her brilliant conclusions, but at that point in the story the villain still has the upper hand. A sarcastic slow clap will most likely be followed by the villain's henchmen apprehending the hero for future interrogations.