### 課程概況

我們生活在一個繁雜的世界，不同的人、企業和政府相互交織，他們的各種行為結合起來，共同產生新穎、意想不到的各種現象。為此，政治起義、市場崩盤和永無止境的社會趨勢浮現在我們眼前，我們如何理解它們呢？運用模型。證據表明，具備模型思維的人表現要優于那些沒有這種思維的人。此外，運用大量模型來思考的人，其表現優于只運用一種模型思考的人。 為什么模型會讓我們成為更好的思考者？ 模型幫助我們更好地組織信息，理清互聯網上多如亂麻的數據。模型幫助我們提高準確預測的能力，幫助我們做出更好的決策，采取更有效的策略，甚至可提高我們設計機構和程序的能力。本課中，我將會介紹一組入門模型：首先介紹臨界點模型，然后是解釋群眾智慧的模型，解釋有些國家富有而有些國家貧窮的原因的模型，以及幫助企業和政治家作出戰略決策的模型。本課涵蓋的模型將為后續社會科學課程奠定基礎，無論是經濟學、政治學、商學或社會學領域。掌握這些材料將為你學習這些進階課程提供很大幫助。此外，這些模型還能在生活中給予你幫助。 課程的安排方式： 對于每個模型，我會提供簡短、易理解的概述講座。然后，我會深入挖掘每個模型的技術細節。這些技術講座不要求微積分知識，但會涉及一些代數內容。所有講座都有對應問題，此外還有一些小測驗，甚至期末考試。如果你決定深入研究，并完成所有測驗和考試，你將獲得結業證明。如果你決定只上入門講座，以初步了解模型，也是可以的。這門課程是完全免費的，但能助你成為更好的思考者！

We live in a complex world with diverse people, firms, and governments whose behaviors aggregate to produce novel, unexpected phenomena. We see political uprisings, market crashes, and a never ending array of social trends. How do we make sense of it? Models. Evidence shows that people who think with models consistently outperform those who don’t. And, moreover people who think with lots of models outperform people who use only one. Why do models make us better thinkers? Models help us to better organize information – to make sense of that fire hose or hairball of data (choose your metaphor) available on the Internet. Models improve our abilities to make accurate forecasts. They help us make better decisions and adopt more effective strategies. They even can improve our ability to design institutions and procedures. In this class, I present a starter kit of models: I start with models of tipping points. I move on to cover models explain the wisdom of crowds, models that show why some countries are rich and some are poor, and models that help unpack the strategic decisions of firm and politicians.

The models covered in this class provide a foundation for future social science classes, whether they be in economics, political science, business, or sociology. Mastering this material will give you a huge leg up in advanced courses. They also help you in life. Here’s how the course will work. For each model, I present a short, easily digestible overview lecture. Then, I’ll dig deeper. I’ll go into the technical details of the model. Those technical lectures won’t require calculus but be prepared for some algebra. For all the lectures, I’ll offer some questions and we’ll have quizzes and even a final exam. If you decide to do the deep dive, and take all the quizzes and the exam, you’ll receive a Course Certificate. If you just decide to follow along for the introductory lectures to gain some exposure that’s fine too. It’s all free. And it’s all here to help make you a better thinker!

### 你將學到什么

Modeling

Economics

Decision-Making

Strategic Thinking

### 課程大綱

周1

完成時間為 3 小時

Why Model & Segregation/Peer Effects

In these lectures, I describe some of the reasons why a person would want to take a modeling course. These reasons fall into four broad categories: 1)To be an intelligent citizen of the world 2) To be a clearer thinker 3) To understand and use data 4) To better decide, strategize, and design. There are two readings for this section. These should be read either after the first video or at the completion of all of the videos.We now jump directly into some models. We contrast two types of models that explain a single phenomenon, namely that people tend to live and interact with people who look, think, and act like themselves. After an introductory lecture, we cover famous models by Schelling and Granovetter that cover these phenomena. We follows those with a fun model about standing ovations that I wrote with my friend John Miller.

12 個視頻 （總計 124 分鐘）, 6 個閱讀材料, 1 個測驗

周2

完成時間為 3 小時

Aggregation & Decision Models

In this section, we explore the mysteries of aggregation, i.e. adding things up. We start by considering how numbers aggregate, focusing on the Central Limit Theorem. We then turn to adding up rules. We consider the Game of Life and one dimensional cellular automata models. Both models show how simple rules can combine to produce interesting phenomena. Last, we consider aggregating preferences. Here we see how individual preferences can be rational, but the aggregates need not be.There exist many great places on the web to read more about the Central Limit Theorem, the Binomial Distribution, Six Sigma, The Game of Life, and so on. I've included some links to get you started. The readings for cellular automata and for diverse preferences are short excerpts from my books Complex Adaptive Social Systems and The Difference Respectively.

12 個視頻 （總計 138 分鐘）, 1 個閱讀材料, 1 個測驗

周3

完成時間為 3 小時

Thinking Electrons: Modeling People & Categorical and Linear Models

In this section, we study various ways that social scientists model people. We study and contrast three different models. The rational actor approach, behavioral models, and rule based models . These lectures provide context for many of the models that follow. There's no specific reading for these lectures though I mention several books on behavioral economics that you may want to consider. Also, if you find the race to the bottom game interesting just type "Rosemary Nagel Race to the Bottom" into a search engine and you'll get several good links. You can also find good introductions to "Zero Intelligence Traders" by typing that in as well.

12 個視頻 （總計 130 分鐘）, 1 個閱讀材料, 1 個測驗

周4

完成時間為 3 小時

Tipping Points & Economic Growth

In this section, we cover tipping points. We focus on two models. A percolation model from physics that we apply to banks and a model of the spread of diseases. The disease model is more complicated so I break that into two parts. The first part focuses on the diffusion. The second part adds recovery. The readings for this section consist of two excerpts from the book I'm writing on models. One covers diffusion. The other covers tips. There is also a technical paper on tipping points that I've included in a link. I wrote it with PJ Lamberson and it will be published in the Quarterly Journal of Political Science. I've included this to provide you a glimpse of what technical social science papers look like. You don't need to read it in full, but I strongly recommend the introduction. It also contains a wonderful reference list.

13 個視頻 （總計 132 分鐘）, 1 個閱讀材料, 1 個測驗

周5

完成時間為 2 小時

Diversity and Innovation & Markov Processes

In this section, we cover some models of problem solving to show the role that diversity plays in innovation. We see how diverse perspectives (problem representations) and heuristics enable groups of problem solvers to outperform individuals. We also introduce some new concepts like "rugged landscapes" and "local optima". In the last lecture, we'll see the awesome power of recombination and how it contributes to growth. The readings for this chapters consist on an excerpt from my book The Difference courtesy of Princeton University Press.

10 個視頻 （總計 99 分鐘）, 1 個閱讀材料, 1 個測驗

周6

完成時間為 28 分鐘

Midterm Exam

1 個測驗

周7

完成時間為 2 小時

Lyapunov Functions & Coordination and Culture

Models can help us to determine the nature of outcomes produced by a system: will the system produce an equilibrium, a cycle, randomness, or complexity? In this set of lectures, we cover Lyapunov Functions. These are a technique that will enable us to identify many systems that go to equilibrium. In addition, they enable us to put bounds on how quickly the equilibrium will be attained. In this set of lectures, we learn the formal definition of Lyapunov Functions and see how to apply them in a variety of settings. We also see where they don't apply and even study a problem where no one knows whether or not the system goes to equilibrium or not.

11 個視頻 （總計 116 分鐘）, 1 個閱讀材料, 1 個測驗

周8

完成時間為 3 小時

Path Dependence & Networks

In this set of lectures, we cover path dependence. We do so using some very simple urn models. The most famous of which is the Polya Process. These models are very simple but they enable us to unpack the logic of what makes a process path dependent. We also relate path dependence to increasing returns and to tipping points. The reading for this lecture is a paper that I wrote that is published in the Quarterly Journal of Political Science

10 個視頻 （總計 122 分鐘）, 1 個閱讀材料, 1 個測驗

周9

完成時間為 2 小時

Randomness and Random Walks & Colonel Blotto

In this section, we first discuss randomness and its various sources. We then discuss how performance can depend on skill and luck, where luck is modeled as randomness. We then learn a basic random walk model, which we apply to the Efficient Market Hypothesis, the ideas that market prices contain all relevant information so that what's left is randomness. We conclude by discussing finite memory random walk model that can be used to model competition. The reading for this section is a paper on distinguishing skill from luck by Michael Mauboussin.

11 個視頻 （總計 79 分鐘）, 1 個閱讀材料, 1 個測驗

周10

完成時間為 2 小時

Prisoners' Dilemma and Collective Action & Mechanism Design

In this section, we cover the Prisoners' Dilemma, Collective Action Problems and Common Pool Resource Problems. We begin by discussion the Prisoners' Dilemma and showing how individual incentives can produce undesirable social outcomes. We then cover seven ways to produce cooperation. Five of these will be covered in the paper by Nowak and Sigmund listed below. We conclude by talking about collective action and common pool resource problems and how they require deep careful thinking to solve. There's a wonderful piece to read on this by the Nobel Prize winner Elinor Ostrom.

9 個視頻 （總計 92 分鐘）, 1 個閱讀材料, 1 個測驗

周11

完成時間為 1 小時

Learning Models: Replicator Dynamics & Prediction and the Many Model Thinker

In this section, we cover replicator dynamics and Fisher's fundamental theorem. Replicator dynamics have been used to explain learning as well as evolution. Fisher's theorem demonstrates how the rate of adaptation increases with the amount of variation. We conclude by describing how to make sense of both Fisher's theorem and our results on six sigma and variation reduction. The readings for this section are very short. The second reading on Fisher's theorem is rather technical. Both are excerpts from Diversity and Complexity.

8 個視頻 （總計 62 分鐘）, 1 個閱讀材料, 1 個測驗

周12

完成時間為 1 小時

Final Exam

The description goes here

### 預備知識

學生應該可以熟練使用基本代數。不需要微積分，但是對用導數求出某點斜率的概念性理解會對課程學習非常有幫助。

### 參考資料

《差異：多元化的力量如何建立更好的團體、企業、學校和社會（新版）》，斯科特·E·佩吉著。

《復雜適應系統：社會生活的計算模型簡介（普林斯頓復雜性研究）》，約翰·米勒和斯科特·佩吉著。

《社會科學模型簡介》，珍妮·拉弗和詹姆斯·馬奇著。