From The New York Times:
Quentin Tarantino's 1994 film Pulp Fiction is packed with memorable dialogue — 'Le Big Mac', say, or Samuel L. Jackson's biblical quotations. But remember this exchange between the two hitmen, played by Jackson and John Travolta? Vincent (Travolta): “Antwan probably didn't expect Marsellus to react like he did, but he had to expect a reaction”. Jules: “It was a foot massage, a foot massage is nothing, I give my mother a foot massage.”
Computer scientists Cristian Danescu-Niculescu-Mizil and Lillian Lee of Cornell University in Ithaca, New York, see the way Jules repeats the word 'a' used by Vincent as a key example of 'convergence' in language. “Jules could have just as naturally not used an article,” says Danescu-Niculescu-Mizil. “For instance, he could have said: 'He just massaged her feet, massaging someone's feet is nothing, I massage my mother's feet.'” The duo show in a new study that such convergence, which is thought to arise from an unconscious urge to gain social approval and to negotiate status, is common in movie dialogue. It “has become so deeply embedded into our ideas of what conversations 'sound like' that the phenomenon occurs even when the person generating the dialogue [the scriptwriter] is not the recipient of the social benefits”, they say.