rom family and friends to strangers on the subway and public figures on 24-hour news cycles, humans recognise an astonishing 5,000 faces, scientists said in a study.

科学家在一项研究中指出，从亲朋好友到地铁上的陌生人，再到24小时新闻循环报道中的公众人物，人类竟然可以分辨出5000张人脸。

Through most of history humans lived in small groups of a hundred or so individuals, a pattern that has changed drastically in recent centuries.

在历史上的大多数时间里，人类都生活在100人左右的小型群体中，但这种模式在近几个世纪里发生了巨大变化。

A study by scientists at Britain's University of York found that our facial recognition abilities allow us to process the thousands of faces we encounter in busy social environments, on our smartphones and our television screens every day.

英国约克大学的科学家进行的一项研究发现，人类的人脸识别能力使人们能够对自己每天在繁忙的社交环境中、智能手机里和电视屏幕上遇到的数千张面孔进行处理。

"In everyday life, we are used to identifying friends, colleagues, and celebrities¹, and many other people by their faces," Rob Jenkins, from York's Department of Psychology², told AFP. "But no one has established how many faces people actually know."

约克大学心理学系的罗布·詹金斯向法新社透露：“在日常生活中，我们习惯于通过面孔辨认朋友、同事、名人和其他许多人。但还没有人确认过人们究竟能识别出多少张面孔。”

For the study, published in the journal Proceedings³ of the Royal Society B, Jenkins and his team asked participants to write down as many faces they could remember from their personal lives.

这项研究发表在英国《皇家学会生物学分会学报》上。为了进行该研究，詹金斯和他的团队要求参与者们尽可能多地记下他们能够想起的生活中的人的面孔。

The volunteers were then asked to do the same with people they recognised but did not know personally.

接着这些志愿者被要求尽可能多地记下自己能认出但在生活中并不认识的人的面孔。

They were also shown thousands of images of famous people -- two photos of each to ensure consistency⁴ -- and asked which ones they recognised.

此外，研究人员还向参与者展示了数千张名人的照片--每个名人有两张照片以确保一致性--并询问他们认出了其中的哪些名人。

The team found an enormous range of the number of faces each participant could recall, from roughly 1,000-10,000.

研究团队发现，每位参与者能够回忆起的人脸的数量存在巨大差异，从大约1000张到1万张不等。

"We found that people know around 5,000 faces on average," Jenkins said. "It seems that whatever mental apparatus⁵ allows us to differentiate⁶ dozens of people also allows us to differentiate thousands of people."

詹金斯表示：“我们发现人们平均大约能识别5000张面孔。看来，我们的思维工具能让我们识别出几十个人，同样也能识别出几千个人。”

The team said it believes this figure -- the first ever baseline of human "facial vocabulary", could aid the development of facial recognition software increasingly used at airports and criminal investigations⁷.

研究团队称，他们认为这一数字--迄今第一个关于人类“面孔词汇量”的基准数目--可能有助于在机场和刑事调查中越来越多使用的面部识别软件的开发。

It may also help scientists better understand cases of mistaken identity.

它也许还能帮助科学家们更好地理解身份被弄错的案例。

"Psychological research in humans has revealed important differences between unfamiliar⁸ and familiar face recognition," said Jenkins. "Unfamiliar faces are often misidentified. Familiar faces are identified very reliably, but we don't know exactly how."

詹金斯表示：“对人类的心理学研究已经揭示了识别陌生面孔和熟悉面孔之间的重要差别。陌生面孔往往会被认错，熟悉的面孔则会被非常确定地认出，但我们不清楚其中的确切机制。”

While the team said it was focused on how many faces humans actually know, they said it might be possible for some people to continue learning to recognise an unlimited⁹ number of faces, given enough practice.

尽管研究团队称此项研究关注的是人类究竟认识多少张面孔，但他们表示，如果进行足够多的练习，有些人也许可以持续学习，从而识别无限数目的面孔。