The technologies of entertainment — from big-screen special effects to the shrinking devices that carry our favorite cultural products to the gym or on an airplane — tend to be warmly embraced by those of us being entertained. But there are exceptions. Consider the machine that a television engineer named Charles Douglass, who died this year at the age of 93, invented in the 1950’s. It was called the Laff Box, and it is responsible for an incalculable number of poor sitcom jokes being greeted with bursts of unearned, prerecorded laughter. Pretty much nobody likes laugh tracks, perhaps because they’re such obvious fig leafs for the embarrassment of weak punch lines, perhaps because they make us feel bossed and condescended to, perhaps because they dehumanize one of the most human actions imaginable. Larry Gelbart, a producer of the TV version of “M*A*S*H,” still complains that the network-enforced use of a laugh track on that show was a trivializing blemish.

In light of all this, it might seem a wonder that the great breakthrough of the Laff Box — its ability to blend recorded laughter and other audience-sound loops to a create a huge range of prefab audible mirth — has been used widely and consistently for decades. But Robert Provine, a professor of psychology at the University of Maryland, Baltimore County, suggests one somewhat uncomfortable answer. “Actually,” he says, “laugh tracks do increase the likelihood that you’ll think a joke is funny and laugh at it. So what Charlie Douglass and company were doing was based in fact.” This is the funny thing about laugh tracks: They work.

One often-cited early study, described in a 1974 issue of the Journal of Personality and Social Psychology, found that subjects who were told a series of jokes both laughed more and rated them as funnier when the jokes were followed by recorded laughter. The canned merriment was described as a form of “conformity pressure,” suggesting that we laugh along in order to fit in. But Provine, who wrote the book on laughter (it’s called Laughter) has little patience for social-science explanations; numerous experiments over more than a decade have convinced him that neurology tells us more.

One of his experiments involved listening in on public conversations and observing when people laughed. “Most laughter in everyday life,” he says, “follows things that aren’t funny.” (Just like in a sitcom!) We don’t generally laugh for conscious reasons. A list of 25 “typical prelaugh comments” included such corkers as “I’ll see you guys later” and “It was nice meeting you, too.” Often the person who laughs first is the one who has just spoken — in what might be thought of as an attempt at a laugh track of one. And while many studies have confirmed the rather obvious idea that laughter is contagious, Provine effectively undercut the “conformity” idea with an experiment. Using a novelty-store gizmo, he simply pressed a button that emitted 19 seconds of laughter, in front of 128 students, in three groups. On the basis of this openly artificial stimulus, more than 90 percent smiled, and nearly half laughed.

Provine speculates about a “laugh detector” hard-wired in our brains, which simply triggers our own titters and guffaws when we hear someone — anyone — else’s. But hard-wiring aside, anyone who has lately sat stone-faced through a “Green Acres” rerun can tell you that canned laughter doesn’t always work. In his laughing-gizmo experiment, Provine found that his students’ reactions to recorded laughter deteriorated quickly; by the 10th laugh blast, some were grimacing. Douglass knew this and sought to improve the technology to give the laugh-manipulators greater flexibility to mix and vary the sounds of recorded laughter so it’s less obvious, and even to “sweeten” the reactions of live studio audiences. He was notoriously secretive about how, exactly, his original Laff Box and its descendants (in use to this day) worked, and apparently even kept the details from his network clients, but he was able to achieve more naturalism by blending an array of carefully culled sound clips.

Still, while it’s easy to convince ourselves that false laughter is both ineffective and a sure sign of desperation, neither seems to be the case. Laugh tracks and sweetening have been used even on such mighty modern-day hits as “Cheers,” “Seinfeld” and “Friends.” So boo and hiss all you want at Charlie Douglass’s innovation; it lives on for reasons that are sound, if not exactly cheering. Contagious laughter, Provine suggests, reveals that we may be taking our conscious will a little more seriously than we should. “The laugh track,” he says, “is a reminder that we’re not the rational, in-control beings that we think that we are.”

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December 28, 2003, The New York Times Magazine.