Researchers led by a University of California, Berkeley, comparative psychologist have found that great apes and chimpanzees, our closest living relatives, 能认出20多年未见的同伴——这是有记录以来最长的非人类记忆的证据.
The findings also bolster the theory that long-term memory in humans, 黑猩猩和倭黑猩猩可能来自我们共同的祖先，他们生活在600万到900万年前.
研究小组使用红外眼球追踪摄像机记录倭黑猩猩和黑猩猩在并排展示其他倭黑猩猩或黑猩猩的图像时注视的地方. One picture was of a stranger; the other was of a bonobo or chimp that the participant had lived with for a year or more.
参与者的眼睛在他们以前生活过的人的照片上停留的时间明显更长, the researchers found, suggesting some degree of recognition. In one case, a bonobo named Louise had not seen her sister, Loretta, or nephew, Erin, for over 26 years. 但当研究人员向路易丝展示他们的照片时，她的眼睛集中在照片上.
"These animals have a rich recognition of each other," said Laura Simone Lewis, 他是正规欧洲杯买球网站伯克利分校心理学系的校长博士后，也是《 the study, which was published today in the journal Proceedings of the National Academy of Sciences
What's more, 参与者看那些与他们有过更多积极关系的人的时间更长, as compared with antagonistic, relationships. In other words, they seemed to recognize friends more than foes.
"We don't know exactly what that representation looks like, but we know that it lasts for years," she said. "This study is showing us not how different we are from other apes, but how similar we are to them and how similar they are to us."
这一发现拓展了人们对动物长期记忆的认识，也提出了进化生物学和心理学的核心问题. Chief among them: How did humans develop such good long-term memory?
Understanding the links between our vivid, 情景记忆和对其他动物的回忆一直是一个研究难题. Previous studies have shown that ravens, for example, remember people who tricked them and can recall social relationships in uncanny ways. 几年以后的社会记忆以前只记录在海豚身上, which studies have found can recognize vocalizations for up to 20 years.
"That, up until this point, 在非人类动物身上发现的最长的长期社会记忆是什么," Lewis said of the dolphin research. “我们在这里展示的是，黑猩猩和倭黑猩猩可能能够记住那么长时间，甚至更长时间."
刘易斯的项目源于对灵长类研究人员的长期观察, who often go months or years between seeing the animals they study. When they returned, 倭黑猩猩和黑猩猩的行为就好像它们从停止的地方重新开始. So the researchers decided to see if that memory hunch was true.
为了得到答案，研究小组开始了一项研究，有时是谱谱研究和剪贴簿研究.
First, 他们需要识别倭黑猩猩和黑猩猩，这些黑猩猩已经与我们可能视为朋友或家人的人分开了. 有时，它们的同伴被转移到其他动物园，以防止近亲繁殖. 其他时候，兄弟姐妹或长辈可能在他们一起生活的时候去世了.
With a list of pairs in hand, sprinkled across zoos in Europe and Japan, researchers needed to track down photos to show the participants. It couldn't be just any snapshot, however. 他们需要一张高质量的照片，拍摄的时间大约是这对情侣最后一次见面的时间. 这对那些最近在高质量照片丰富的时代被分开的动物来说有点容易. 事实证明，对于其他人来说，这要棘手得多，比如路易斯的亲戚，他们在1995年左右分居.
The team ended up being able to show images to 26 bonobos and chimpanzees.
黑猩猩和倭黑猩猩能认出25年未见的同伴的照片，对朋友的照片反应更热烈, a new study finds.
在安装了装有敏感摄像头和非侵入性眼球追踪工具的计算机系统之后, participating animals were allowed to enter the room voluntarily. Their compensation? A bottle filled with diluted juice. (Bonobos and chimps love fruit juice and eat lots of fruit in the wild.)
当他们啜饮时，他们面前的屏幕在成对的图像之间交替. The cameras monitored where the animals' eyes wandered. 计算机记录每张图像花费的时间精确到几分之一秒，研究小组将在几个月后对这些数据进行梳理.
“这是一个非常简单的测试:他们是否会更长时间地盯着之前的同伴看, or are they looking longer at the stranger?" Lewis said. "And we found that, yes, 他们会花更长时间看之前同伴的照片."
Laura Simone Lewis
These are the next questions for Lewis. Born and raised in Berkeley, 刘易斯曾就读于杜克大学和哈佛大学，并在圣何塞大学担任研究员. Andrews. Lewis' co-authors include researchers from Harvard, Johns Hopkins University, Kyoto University, 比利时安特卫普大学和德国康斯坦茨大学.
刘易斯说，她和其他人特别担心，当参与者看到他们多年未见的亲戚的照片时，他们会有什么反应. As the project began, zookeepers monitored the animals for signs of stress. But they didn't show any markers of agitation. Instead, when images of a once-close relative appeared on the screen, the participants would sometimes stop drinking the juice entirely, seemingly mesmerized by the image.
研究表明，大脑在识别图像时发生了一些变化. What's unclear is what kind of memories they were. Could they have been rich, episodic narratives like humans have? Might there have been some fleeting curiosity about why they saw this? Can they extrapolate what those relatives might look like today?
Lewis returned to Berkeley earlier this year as a postdoctoral fellow. It was a homecoming of sorts, she said, 她计划继续提出一些大问题，欧洲杯买球最亲近的祖先能教给我们什么欧洲杯买球记忆的东西. Partly it's out of a curiosity that drives science. It's also out of a determination to conserve the habitats that are home to endangered bonobos — animals that can teach us about ourselves.
刘易斯说:“这项研究提醒我们，我们与地球上行走的其他物种是多么相似。. "And therefore, how important it is to protect them."
