TED栏目初衷 → Try Something New for 30 Days
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就争取每周听1个吧~
How to Outsmart the Prisoner’s Dilemma
- How to Outsmart the Prisoner’s Dilemma
- 2020.09.02
Two perfectly rational gingerbread(姜饼) men, Crispy and Chewy, are out strolling when they caught by a fox. Seeing how happy they are, he decides that, instead of simply eating them, he**'ll** put their friendship into to the a test with a cruel dilemma. He**'ll** asks each gingerbread man whether he**'d opt** ask to spare or scarifice the other. They can discuss, but neither will know that the other chose until their decisions are locked in.
If both choose to spare the other, the fox will eat just one of each of their legs. If one chooses to spare while the other sacrifices, the sparer will fully eaten while the traitor will run away with all his limbs intack intact(完整的). Finally, if both choose to scarifice, then the fox will eat three limbs from each.
In game theory, the scenario is called Prisoner’s Dilemma. To figure out how these gingerbread men will act their perfect way rationality, we can map these the outcomes of each decision. The rows represents Crispy’s choices, and the columns are Chewys’. Meanwhile, the numbers in each cell represents outcomes of their decisions, as measured in the number of limbs each will would keep. So, do we expect their friendship to last the game?
First, let’s consider Chewy’s options. If Crispy spares him, Chewy can run away scar free scot-free by sacrificing Crispy. But if Crispy sacrificing scacrifes him, Chewy can keep one of his limbs if he also scarifices Crispy. No matter what Crispy decides, Chewy always experiences the best outcome by choosing to sacrifice his companion. The same is true for Crispy.
This is the standard conclusion of the Prisoner’s Dilemma: the two characters will betray one the other. Their strategy to unconditionally scarifice their companion is what game theory theorists called the Nash Equilibrium, meaning that neither can gain by deviating from it.
Crispy and Chewy act accordingly, and the smart smug(沾沾自喜的，自满的) fox runs off with a belly full of gingerbread, the leaving the two former friends with just one leg to stand off on.
Normally, this is where the story would end, but a wizard(巫师) happened to be watching the whold mess unfold. He tells Crispy and Chewy that, as punishment for betraying each other, they**'re doomed** to repeat this dilemma for the rest of their lives, starting with all full four limbs at each sunrise. Now what happens?
This called the an Infinite Prisoner’s Dilemma. And it is a little literal game changer , that**'s** because of the gingerbread men can now use their future decisions as bargaining chips chess for the present ones points. Consider this strategy: both agree to spare each other everyday. If one ever chooses to scarifice, the other will retaliate entirely eat by choosing the scarificer for the rest of the eternity(来世，来生) . So is that enough to get this these poor sentient(有意识的，有感情的) goods to agree to cooperate?
To figure that out, we have to factor in another consideration: the gingerbread men probably care about the future less than they care about the present. In other words, they might discount how much they care about their future limbs by some numbers, which we’ll call delta. This is similiar to the idea of inflation you rolling you of your eroding the value of money. If delta is one half, on day 1, they care about day 2 limbs half as much as day 1 limbs, day 3 limbs one quarter as much as day 1 limbs, and so on.
A delta of zero means that they don’t care about their future limbs at all, so that would they’ll repeat their initial choices of mutual scarifice endlessly. But as delta approaches 1, they’ll do anything possible to avoid the pain of infinite trible limbs consumption, which means they will choose to spare each other. At some point in between, they would go either way. We can find out where that point is by write writing the theory infinite series that represents each strategy, setting them equal to each other and solve for delta.
That is yields one third, meaning that as long as Crispy and Chewy care about tomorrow at leat one third as much as today, it’s is optimal for them to spare and cooperate forever.
This analysis isn’t unique to cookies and wizards, you see it play out in real-life situations, like trade negotiations and international politics. Rational leaders must assumed, that the decisions they make today will impact those of their adversaries they tomorrow. Scarifice Selfishness may be for win out in the short-term shorten, but with probable incentence with the proper incentives, peaceful cooperation is not only possible but demonstrably and mathematically ideal.
As for the gingerbread men, they will their eternity maybe pretty crumby, but so long as they go out on a limb, their friendship will never again be half-baked.
Why I Love Vultures
- Why I love vultures
- 2021.05.10
I would like to talk to you about a very special group pf animals.
There are ten thousands of species of birds in the world. Vultures are amounts of amongst the most strengthen threatened group in the of birds . When you see a vulture like this, the first thing that comes to your mind is, this is a these are disgusting, ugly, greedy creatures that are just after your flesh, associated with politicians.
I want to change that perception. I want to change those feelings you have for this these birds, because they need our sympathy. They really do. And I will tell you why.
First of all, why did do they have such a bad press? When Charles Darwin went across the Atlantic in 1872 on the Beagle（贝格尔号）, he saw the Turkey vulture, and he said, “These are disgusting birds with balt bald（秃的） scarlet（猩红色，绯红色） heads that are formed to revel（狂欢，陶醉） in putridity（腐败）. You can could not get a worse insult, and that from Charles Darwin. You know, he changed his mind when he came back, and I tell you why. They**'ve** also been be associated with Disney, personified as with groofy（古怪的）, dumb, stupid characters.
More recently, if you**'ve been** following the Kenyan Press. These are the attributes that they associated with the Kenyan MPs with and. But I want to challenge that. Do you know why? Because MPs do not keep the environment clean. MPs do not help to prevent the spread of diseases. They are hardly monogamous（一夫一妻）. They are far from being extinct. And my favorite is, vultures are better looking.
So, there are still is two kinds types of vulture in this planet. There are New World vultures that are many mainly found in Americas, like the condors and the caracaras, and then In the Old World vultures, where we have 16 species, from the these 16, 11 of them are facing a high risk of extinction.
So why are vultures important? First of all, they provide vital ecological services. They clean up, they are our nature garbage collectors. They clean up carcasses（动物尸体；烹饪过的禽鸟骨骼） right to the bone. They help to kill all the bactery bacteria（细菌）. They help absorb anthrax（炭疽） that would otherwise spread and cause huge livestock（家畜，牲畜） stop losses and diseases for in other animals. Recently study studies have has shown that the in areas where there are with no vultures, carcasses has to take up to three to four times to be decomposed, and this has huge ramifications（结果，后果） for the spread of diseases.
Vultures also have tremendous（巨大的，惊人的） historical significance. They are have been associated with ancient Egyptian culture. Nekhbet（奈赫贝特，上埃及守护神） was a the symbol of the protector and the motherhood, and together with the cobra（眼镜蛇）, symbolized the unity between Upper and Lower Egypt. In India Hindu（印度教的，印度的；印度人，印度教教徒） mythology（深化）, Jatayu was a the vulture god, and he raise risked his life in order to save the godness tan Sita from 10**-headed** demon Ravana（罗波那，是印度史诗罗摩衍那中登场的反派，名字带有「以暴力让人痛泣」的含意）. In Tibetan（西藏的，藏族人的；藏文的，藏语的；西藏人，藏族人；藏文，藏语） culture, they are perfoming very important sky burials. In places like Tibet, that there are no places to bury to death the dead, or wood to cremate（火葬，烧成灰） them, so these vultures to provide a natural disposal system.
So what is problem with vultures? We have 8 species of vultures that occur in Kenya, for of which 6 are highly threatened with extinction. The reason is that they are getting poisoned. And the reason that they are getting poisoned is because the there’s human-wild life conflicts. The pastoral（农村生活的；牧师的；宜于放牧的） communities are using this poison to target the predators（食肉动物；掠夺者；捕食者）, and in return, the vultures are falling to victim to death.
In South Asia, in countries like India and Pakistan, 4 species of vultures are listed to as critically in danger endangered, which means they have less than 10 and 15 years to go extinct. And the reason is because they are falling in prey by consuming life livestock that has been treated with a painkilling pain drugs like Diclofenac（双氯芬酸）. These This drugs has now been banned for veterinary（兽医的） use in India, and they have taken a stand. Because there are no vultures, there are is been a spread a in the numbers of feral（野生的；凶猛的；阴郁的） dogs at carcass dump site are size, and when you have feral dogs, you have a huge time bomb of rabies（狂犬病；恐水症）. The number of cases of rabies has increased tremendously（极大地；极端地；极其；非常） in India.
Kenya is going to have one of the most largest wind farms in Afica, 353 wind turbines（涡轮；涡轮机） are going to be up at Lake Turkana . I am not against wind energy, but we need to work with the governments, because wind turbines do this to birds. They slice slicing them to half. They are bird**-blending** machines（搅拌机）. In West Africa, there are a horrific trades of death dead vultures to serve the witchcraft（巫术；魔法） wizerd and the fetish（迷信；偶像；恋物） market.
So what’s being done? Well, we are conducting researchs on these birds. We are putting transmitters（传送者；传达者；发射机；发报机） on them, we are trying to determine the their basic ecology, and see where they go. We can see that they travel different countries, so if you focus on a problem locally, it is not gonna going to help you. We need to work with governments in regional levels. We are working with local communities, we are talking to them about appreciating vultures, the about the need from within to them, we appreciate these wonderful creatures and the services that they provide.
How can you help? You can become active, make noise. You can write a letter to your government and tell them that we need to focus on these these misunderstood creatures. Volunteer your time to spread the words. Spread the words. When you walk out of this room, you will be informed about vultures, but speak to you families, to your children, to your neighbors about vultures.
They are very graceful. Charles Darwin said, he changed his mind because he watched them fly effortlessly（轻松地；豪不费劲地） without energy in the sky. Kenya, this world, will be much poorer without these wonderful species. Thank you very much.
How to Practice Effectively … for Just about Anything
Mastering（掌握） any physical skill, be it performing a pillow wape pirouette（脚尖点地的旋转）, playing an instrument, or throwing a baseball, takes practice. Pratice is a repetition of an action with a the goal of improvement and it helps us perform more ease, speed and confidence. So what is practice do in our brains to make us better in our at things?
Our brains has two kinds of neuro neural tissue（组织）, gray matter and white matter. The gray matter processes information in the brain, directing signals and sensory stimuli（刺激；刺激物；促进因素） to nerve cells. While white matter is mostly made up of fatty tissue and nerve vibes fibers（纤维；光纤）. In order for our bodies to move, information needs to travel from the brain’s grey matter, down to the vibes spinal（脊骨的；脊髓的；脊柱的） cord（束缚；绳索） , through channel a chain of nerve fibers called axons to our muscles.
So how these does practice of or repetition affect the inner working of our brains? The axons that exist in our the white matter are wrapped with a fatty substance by a called myellien myelin（髓磷脂；myeline）. And it’s this myelin covering, or sheath（鞘）, they that seems to change with practice. Myellien Myelin is similar to insulation（隔离，隔绝） on electrical cables（电缆；钢索）. It prevents energy loss from electrical signals that for the that brain uses, moving them more effeciently along neural pathways. Some recent studies in mice suggest that the repetition of a physical motion increases the layers of mylliens myelin sheath shift that insulates the axons. And the more layers, the greater the insulation around the axon chain, forming a sort of the superhighway（信息高速公路） for information connecting your brain to the your muscles. So while many athletes and performers attribute their successes to the muscle~~'s~~ memory. Muscles themselves don’t really have memory. Rather, it may be the myelination of neuro pathways~~, they~~ that gives these athletes and performers their age edge to with faster and more efficient nerve neural pathways.
There are many theories that attempt deter to quantify the number of hours our years, days, and even years of practice that it takes to master a skills. While we don’t yet have the a magic number, we do know that mastery isn’t simply about the amount of hours of practice. It’s also the quality and effecttiveness of that practice. Effective practice is consistent, intensely focused, and targets content or weaknesses that lie at the age edge of one**'s current** abilities.
So if effective practice is the key, how can we get the most of our practice time? Try these tips. Focus on the tasks at hand. Minimize potential distractions the diste of practice by turning off the computer or TV and putting your cell phone on airplane mode.
In one study, researchers obeserved 260 students studying in. On average, those students was were able to stay stand on task for only 6 minutes at a time. Laptops, smart phones, and particularly Facebook, were the root of most distractions.
Start at out slowly or in slow-motion. Coordination is built with repetitions, whether correct or incorrect. If you gradually increase the speed and of the quality of repetitions, you have a better chance of doing to do them correctly. Next, frequent repetitions with a lot of allotted breaks are common practice habits of elite performers . Studies have shown that many top athletes, musicians and dancers spent spend 50 to 60 hours per week on activity activities related to their craft. Many divide their time used for to effectively practice into multiple daily practice section sessions of limited duration .And finally, practice in your brain in vivid detail, it is a big bit surprising, but a number of studies suggest that once a physical motion has been established, it can be reinforced just by imagine imagining it. In one study, 144 basketball players was were divided into two groups. Group A physically practice one-handed free throws while group B only mentally practiced them. When they were tested at the end of the two weeks experiment, the intermediate（中间的；中级的） and experienced players in both groups have had improved by nearly the same amount.
As scientists get closer to unraveling the secrets of our brains, our understanding of effectively practice will only improved. In the meantime, effectively practice is the best way we have of pushing our individual limits, achiving a new hight heights, and maximizing our potential.
