The very small brains of bees are still good enough to recognize different human faces.
Scientist has trained a troupe of bees to recognize different human faces by rewarding them with a sucrose①solution when they visited a particular photograph.
Other photographs visited by the seven bees bore only a bitter quinine② solution and the bees， despite having brains the size of pin heads， were able to remember the sweet faces， even when the pictures were mixed up and after a gap of two days.
Five of the seven made a beeline to the sucrose faces even when the solution was removed， ruling out the possibility that their sense of smell was responsible.
Scientist said that research had been going on into whether or not the human brain required specialized regions to process faces reliably.
In addition， thought that it would be interesting to know whether a miniature brain would be able to solve a face recognition task， adding that the scientist chose bees as they were more motivated③ and hard-working than other insects.
① sucrosen. ［化］蔗糖
② quininen. ［化］金鸡纳碱；［药］奎宁
③ motivatedadj. 有动机的，有目的的；有积极性的
蜜蜂能准确辨别人的面孔
尽管蜜蜂的脑部体积很小，但它们却能够准确地辨别出不同人的面孔。
有科学家对7只蜜蜂进行了识别人的面孔的训练。他们准备数张不同人的面部照片。当蜜蜂去看一张特定的照片时，研究人员给它们糖水以示鼓励，而蜜蜂去看其它照片时，只能尝到研究人员提供的苦涩溶液。
两天之后，所有的照片被混合起来。结果，令人惊喜的是，尽管蜜蜂大脑的体积只有大头针那么大，但它们却记住了能让它们得到糖水的那张照片。
7只蜜蜂中的5只竟然直接飞到了它们曾被奖励了糖水的那张照片，而实验室里的糖水却早已被移走，这就排除了蜜蜂是根据对糖味的嗅觉而找到那张照片的可能性。
对此，科学家们之所以选择蜜蜂而不是其他昆虫来进行实验，是因为蜜蜂比其它昆虫更加积极和辛勤地劳动；此外，大脑体积如此微小的蜜蜂是否能够完成诸如识别人类面孔这样复杂的任务也是科学家们想知道的。