Through decades of scientific research, scientists have locked the species closest to humans in chimpanzees. There may be only one difference between humans and chimpanzees. After studying their genes, researchers have expanded their horizons to a new direction, that is, comparing their differences through brain activity. Related papers have been published in the latest issue of Proceedings of the National Academy of Sciences.
The experiment put chimpanzees at rest.
"The biggest difference between humans and chimpanzees is the brain-the brain capacity of humans is much larger than that of chimpanzees." Researcher Huang Wanbo from the Institute of vertebrate paleontology and Paleoanthropology, Chinese Academy of Sciences pointed out that the brain capacity of chimpanzees is generally only 400 ml, while that of human beings is 1400- 1500 ml. This has almost become an insurmountable gap between chimpanzees and humans.
The huge difference in brain capacity has always made people think that chimpanzees and humans have great differences in thinking. However, a new study overturns the original view. The executor of this study pointed out that the similarity of brain activities between chimpanzees and humans is far beyond our imagination. Of course, you know, even so, there are obvious differences between the two.
Daily Science, a famous American science website, commented on this new study: "This study is undoubtedly important. This is the first time to compare the brain activities of the two. Through research, it shows us the uniqueness of human beings. Even the recent chimpanzees are different from humans, even if this difference is far from what we imagined. "
The research team is an international team, and JamesRilling of yerkes National Primate Research Center of Emory University is the team leader. He led other researchers through positron emission tomography (PET) to study the differences between eight people and five chimpanzees in the state of "static activity" of the brain.
The resting state usually defined by researchers refers to: the subject is awake and resting on the examination bed; Close your eyes and breathe quietly; Fix the head to minimize the active and passive movements of the head and other parts; Meanwhile, try not to do any thinking activities. In recent years, a series of studies have found that primate brains also have functional activities in a static state without tasks. This phenomenon has aroused great interest of researchers, because most of the previous fMRI brain functional imaging studies related to specific tasks were based on the rest state without tasks. The brain functional activities defined by them are obtained by subtracting the task state from the rest state. Studies have shown that 50% of the brain's energy consumption at rest is related to synaptic transmission function, which indicates that there are a lot of synaptic activities at rest, and there may be important brain functional activities at rest. "At present, the study of resting brain activity is a hot field. Resting brain activity is mainly related to speech area and free association, which is also to maintain the awake state of the brain. " Luo Jin, a researcher mainly engaged in brain cognitive research at the Institute of Psychology, Chinese Academy of Sciences, pointed out.
Through research, researchers have found that there are organized brain functional activities at rest, which are closely related to the monitoring of the internal and external environment of the brain, plot memory and self-awareness. Chimpanzees are our close relatives. They can even recognize themselves in the mirror. All this is enough to prove that chimpanzees have innate self-knowledge.
On this premise, the research team designed the experiment. They put five chimpanzees in cages, forbade them to communicate with each other, and tried to keep them "at rest". During the experiment, three chimpanzees lay down more times than standing, sitting or even moving, while the fourth chimpanzee sat more times.
The researchers used PET to monitor the brain activity of these chimpanzees at rest, and then compared it with the brain activity maps of eight experimenters.
The cognitive activities of human resting state mainly involve memories of the past, plans for the future, inner meditation and so on. At this time, there will be activity trends in some areas of the brain. These brain regions mainly include medial prefrontal lobe, anterior cingulate gyrus, posterior cingulate gyrus and bilateral inferior parietal lobules. Like humans, the medial frontal lobe and middle frontal lobe of chimpanzee brain also show strong activity. The difference is that the activity of the medial prefrontal lobe is mainly concentrated in the back of human beings, while the activity of chimpanzees is mainly concentrated in the front.
In the eyes of researchers, this kind of brain activity suggests some interesting things. They show that chimpanzees have the same intellectual self-reflection function as humans. "This means that chimpanzees can imagine things they have never encountered. Chimpanzees can imagine the future, and now the means of transportation are for future use. "
In addition, chimpanzees and humans have very similar activities in the frontal pole. Frontal pole is located at the forefront of frontal lobe, which is closely related to many parts. Frontal pole is the center of advanced mental activity, which has an important relationship with the regulation of autonomic nervous function. For humans, this area is mainly used for thinking and memory. If the function of this brain region is also possessed by chimpanzees, it means that chimpanzees also have the ability of human thinking activities. Researchers believe that this brain activity of chimpanzees at rest also shows that they have a strong memory, and can recall where the food was put 16 hours ago.
The researchers pointed out that the scanning comparison of brain activity between the two shows that "long-term planning and short-term arrangement" for the future may not be a patent of human beings. Perhaps as early as millions of years ago, the original planning ability appeared in our ape ancestors.
At the same time, German scientists have come to a similar view through animal behavior research. In order to test the planning ability of chimpanzees, scientists at the Max Planck Institute for Human Evolution in Germany designed an experiment. They let chimpanzees stay in a room for five minutes. There is a food container that chimpanzees can see but can't touch. There are eight tools, only two of which are suitable for opening the container.
Later, the researchers asked chimpanzees to leave the laboratory with any tools they wanted, and took other tools and put food containers where they could get them. Then, they let the chimpanzees go back to this room-if they had chosen the right tools before, they could open the container and eat food.
After several attempts, all the chimpanzees in the experiment learned how to choose the right tools. Surprisingly, after giving them a day's rest and repeating the experiment, they still remember what tools they should bring.
However, if chimpanzees can get food directly without using tools to open food containers after returning to their original rooms, scientists find that chimpanzees begin to bring back the wrong tools. Scientists say this at least shows that chimpanzees have taken the right tools to prevent the possible work of opening containers to eat. This is because they are planning for future activities, which has nothing to do with the connection between tools and food rewards in general experiments.