4 . Overhear any conversation or pay close attention to your own, and you will hear laughter. You will probably also notice that, more often than not, the laughter is in response to something that was not very funny—or was not funny at all. Take Hillary Clinton’s strategic laughter during heated exchanges with Donald Trump in the presidential debates.
In one research in my Vocal Communication Lab at UCLA, we played recorded laughs to listeners and asked them, “Is this laugh ‘real’ or ‘fake’?” Our recorded laughs were either taken from real conversations between friends in a laboratory setting, or produced by request, also in the lab. It turned out that about 70 per cent of the listeners were able to tell the “real” laughs from the “fake” ones. Quite a few fake laughs sound pretty good, but why are fake laughs not as convincing as we expect? We can detect part of a laugh that is hard to fake—and that part has to do with the control of our breath.
Laughs could essentially be broken up into two different vocalisation (发声) systems: speech and emotion. Although both kinds of laughs are vocalised as “ha-ha-ha,” the intermittent breaths a person takes in—between the sounds give away a fake laugh. Real laughs have a higher proportion of breathy parts in between. Think about every time you force a laugh. You have to actually say the “ha-ha-ha,” and probably never consider how you breathe while doing it.
A fake laugh is basically an imitation of a real laugh. If you slow down a real laugh about two and a half times, it sounds like an ape (猿). But a slowed fake laugh sounds more like human speech. We put this observation to the test with the slowed-down versions of the laughs used for our first experiment, and asked participants whether the recordings were from a human or an animal. Though they couldn’t tell the origin of the real laugh, they were able to tell that the fake laugh came from a human.
Real laughs are produced by an emotional vocal system that humans share with all primates (灵长目动物), whereas fake laughs are produced by a speech system that is unique to humans. Laughter in humans likely evolved from play vocalisations in our primate ancestors. If one animal bites another during a rough-and-tumble (小打小闹的) play, it could be taken as an attack. But if they signal while panting (喘气) that they are just playing, the play can continue without being interrupted by an unnecessary real fight. In this way, real laughter reveals our animal nature.
1. Fake laughter is easy to detect because _________.
| A．it is not in a real conversation |
| B．it responds to something that is not funny |
| C．its control of breath is different |
| D．it sounds too good to be true |
2. A fake laughter sounds more like _________.
| A．human emotion | B．human speech |
| C．ape emotion | D．ape nature |
3. Which of the following statements is NOT true according to the passage?
| A．Fake laugh is an imitation of real laugh. |
| B．Real laugh demonstrates our animal nature. |
| C．Humans and apes share an emotional vocal system. |
| D．A speech vocal system is unique to primates. |
