IT IS received wisdom that humanity owes a lot of its evolutionary success to its remarkable ability to communicate. So much so, in fact, that few have bothered to test this hypothesis in any systematic way. Now, a group of researchers led by Andrew King, of the Royal Veterinary College in Britain, has tried to plug this gaping hole. Their first results have just been published in Biology Letters.

人类得以划时代的进步的一个重大因素在于其值得称道的交流能力,这一结论为世人所公认。人们对此深信不疑,实际上甚至都鲜有人费工夫去系统地验证一下这个假设。而现在,英国皇家兽医学院的Andrew King带领的一支研究小组正在尝试填补这个缺口。他们的第一批研究成果近期刊登在了《生物学快报》期刊上。

Hunter-gatherers’ practice of scouring their surroundings for edible plants is responsible for half of the name anthropologists have bestowed on them. And for good reason. With hunting likely to have been an intermittent diversion, effective foraging would have been crucial to tiding early humans over to the next woolly mammoth. So Dr King and his colleagues conducted a study to see how, if at all, communication enhances foraging prowess.

搜索周边环境找寻可供食用的植物的捕猎采集型行为是人类学家们之所以认为语言交流如此重要的一部分原因。这么说也挺有道理。由于捕猎很容易时不时就改变方向,因此有效地觅食对于使远古人类群体性转向下一个猎物是至关重要的。因此,King博士和他的同事们实行了一次研究,调查交流是否对搜寻能力起到了强化作用。

They recruited 121 visitors to, rather appropriately, the London Zoo, and split them into 43 groups. Each group contained between two and seven people. Some were single-sex and some mixed. Some were composed of family and friends whereas others brought together complete strangers. Half the groups were allowed to communicate freely. The rest were told to exchange no verbal signals or gestures of any kind.

他们非常合适地募集了121名伦敦动物园的参观者并将它们分为43组。每组包含2-7个人。其中一些组的成员性别相同,另外一些则是有男有女。部分组的成员中有家人或朋友,其他的则是由完全陌生的人组成的。这些组中的一半被允许自由交流,而其余的则被要求不得进行任何形式的语言信号或动作交流。

Each group was then asked to a room containing six foraging patches—boxes filled with 300 cards, some green and some white—arranged at a distance from a central home base. The green cards were defined as good and the patches varied from 5% to 95% green. The foragers could not see inside the boxes and were allowed to pick only one card at a time, through a hand hole, using their dominant hand. There were no restrictions on which patches to visit, but each time a card was plucked it had to be returned to the home base, irrespective of colour. The goal was to collect as many good cards as possible in an unspecified short period of time (all trials actually lasted ten minutes). As an incentive, members of the best-performing group would receive an animal-adoption prize worth £30 ($47).

接下来各组被请进一间有6个采集区域的屋子,其中有几个大盒子装着300张卡片,有些是绿色的,有些是白色的。这些箱子被安置在距离屋子中间的聚点较远的地方。绿色的卡片被定义为好的卡片,并且每个采集区都有数量在5%-95%之间的绿色卡片。搜寻者看不到盒子里面,并且被要求只能用他们习惯用的那只手每次从箱子的洞里拿一张出来。对于去哪个采集区去找是没有限制的,但是不管是什么颜色的,每次只要卡被拿出来就必须交到屋子里的聚集点处。目标是在一个没有规定长度的短时间内收集到尽可能多的好卡片(实际上所有的实验都持续10分钟)。作为激励,干得最漂亮的那组的成员会得到一个价值30磅(47美元)的动物收养奖励。

Before the modern-day foragers were let loose, radio-frequency tags, like those used in swipe cards, were wrapped around everyone’s dominant wrist. All the good forage cards were similarly tagged. These, together with antennae on top of the boxes and in the home base, allowed Dr King to track the group members’ precise movements. That, in turn, made it possible to determine how long it took each group to reach a consensus, defined as concentrating more than 90% of activity around a single patch.

在这些现代搜寻者解散去拿卡片之前,每个人的习惯用手的手腕上都带上了一个类似IC卡式的无线电频标签。这些标签再加上箱子上面和屋子的聚集点处装的无线电天线使得King博士得以追踪各组成员的准确行动。接下来也就可以知道每组成员分别花了多长时间达成共识,其标准为90%以上的活动围绕同一个采集点。

Unsurprisingly, the groups that were allowed to communicate proved the more effective foragers. They were much likelier than their non-communicating peers to converge on the greenest patches. What did come as something of a surprise, however, was the nature of the communication that mattered. The researchers monitored noise levels and hand gestures. Noise levels served as a proxy for verbal communication; gestures, for the non-verbal sort. Dr King found that the only thing which explained the probability of lighting on the best patch was gesture use, which peaked just before consensus was reached. Noise levels remained more or less constant the whole time, suggesting that verbal messages were not as important.

不出所料,那些被允许交流的组证明是更有效率的搜寻者。比起那些不能交流的同伴来讲,他们在哪一箱有最多的绿色卡片上更有可能达成共识。然而令人惊讶的结果却是实质起作用的交流的性质。调研员们监控了噪音水平和肢体语言。噪音水平代表了语言交流,而肢体语言则代表非语言类交流。King博士发现,只有一个原因能够解释最有可能在最佳采集点上达到共识的方式是采用肢体语言,这种方式恰巧在共识将将要达成前达到顶峰。自始至终噪音水平都保持在一个大约不变的程度上,这显示了语言信息并没有那么重要。

Constant volume may hide the variable importance of what was said. So, Dr King plans to repeat the experiment, controlling for the meaning of both utterances and gestures. Moreover, hand gestures are a relatively local signal. It remains an open question whether they are as crucial to success in groups larger than the half-dozen or so people typical of foraging parties in hunter-gatherer societies. Spoken contributions allow information to be disseminated rapidly to group members far away. That may trump the importance of non-verbal messages as groups grow larger. But if gestures convey some vital extra information, people in larger groups may limit their communication to nearby co-foragers. This might lead to the emergence of subgroups.

持续不变的噪音量可能导致说话内容重要性的变化情况被隐藏。于是King博士计划再进行一次这个实验,这次对讲话与肢体语言的含义进行控制。此外,手势相对来讲是一种更加区域性的信号。同样需要探讨的问题是,对于比起那些以捕猎采集为主业的社会中典型的6人左右的搜寻组织规模大的小组来讲,肢体语言是否也一样是成功的关键。语言表达的贡献在于其使得信息可以快速传达到距离较远的小组成员处。这就使语言表达可能会在小组规模增大时超越非语言信息的重要性级别。但如果肢体语言表达了一些附加的重要信息,较大的组中的成员可能会将他们的交流对象限制在附近的搜寻伙伴中。这或许会导致组内小群体的产生。

How all this pertains to the “hunter” in “hunter-gatherer” has yet to be investigated. Getting a project on that past an ethics committee might involve an interesting act of communication in its own right.

而这一切与“捕猎采集型社会”中的捕猎者的关系仍有待调查。由道德委员会通过开始这样一个项目或许本来就包含着一个有趣的交流行为。