## History #11: Agriculture

This the sixth post in an ongoing big history series. It follows the structure of the course developed by historian David Christian. This post will explore the origins of agriculture and modern civilizations.

Past posts can be found here: The Big Bang, Star Formation, Solar Systems, Life, Collective Learning

## Human Nature #11: Social Proof

In the 1950s, Solomon Asch developed an experiment to study how individuals yielded to or defied a majority group. A group of 8 students would be shown a card with a reference line on it. The line was a certain length, let’s say 1 inch. The group was then shown three different lines and asked which line best matched the reference. Two of the lines were clearly longer or shorter and one matched perfectly.

The trick was that 7 of the 8 students were confederates, people who were in on the experiment. In the first round, the confederates were all instructed to give the right answer. The test subjects also gave the right answer. But in the third round, the confederates were instructed to give the same wrong answer. The test subjects also gave the same wrong answer.

What happened here? Why did the test subject give a clearly wrong answer just because other people were doing it? This is the subject of today post.

## Numeracy #11: Statistical Significance

Imagine you just developed a new strategy for coin flipping. Right before you release the coin, you blink 4 times. You want to test if this strategy will result in more heads than tails, so you set up a test where you flip a coin 20 times. You observe 13 heads and 7 tails. Your strategy resulted in heads 65% of the time! You rush out to start gambling on coin flips.

You probably already realized the error in our analysis. Even if our new strategy had zero impact, we would still expect to flip 13 heads about 7.3% of the time. This raises an important question: how do we know if our results are the product of our strategy or randomness? We don’t, but we can set up our experiment in a way that the odds of a random result are so small, that we are confident the effect is from our strategy.

## Investment Theory #10: Buffett’s 1965 Letter

In 1956, Warren Buffett concluded his work for Benjamin Graham and returned to Omaha, where he started an investment partnership. This partnership was formed with seven limited partners, made up of family and friends, contributing \$105,000, and Warren Buffet contributing \$100. It grew over time.

This post continues my series about that partnership. The goal is to gain some insight into one of the most successful investment vehicles in modern history.

Links to past years can be found here: 1957, 1958, 1959, 1960, 1961, 1962, 1963, 1964

## Natural Science #10: Entropy

Back in the 19th century, at the height of the industrial revolution, engineers were pondering questions about the efficiency of steam engines. From those questions, arose the science of thermodynamics. You might be familiar with the laws they came up with:

1. Energy cannot be created nor destroyed in an isolated system.
2. The entropy of any isolated system always increase.
3. The entropy of a system approaches a constant value as the temperature approaches absolute zero.

Today’s post will explore that second law of thermodynamics, which also happens to be the most important for understanding time and the evolution of the universe.

## History #10: Collective Learning

This the fifth post in an ongoing big history series. It follows the structure of the course developed by historian David Christian. This post will explore the origins of humans and collective learning.

Past posts can be found here: The Big Bang, Star Formation, Solar Systems, Life

## Human Nature #10: Reciprocity

Imagine you are eating at a restaurant with a coworker. You both engage in some small talk and then the check comes. As would be expected, you both dive for it. Your coworker was a bit faster. You offer to pay, but the coworker just says you can get it next time.

You just landed a free lunch but something doesn’t feel right. You don’t like being indebted to someone even if it’s insignificant. The next day at work, your coworker asks for some help with a project. You jump at the opportunity to balance the scale.

If you can relate to this, you would be victim to the rule of reciprocity that Robert Cialdini popularized in his book Influence: They Psychology of Persuasion. If the significance of this isn’t apparent, here’s Sheldon Cooper to explain (excuse the laugh track).

## Numeracy #10: Nash Equilibrium

Imagine two criminals, Bob and Sam, who were arrested today for selling drugs. It’s an open and shut case, but the district attorney has a hunch that Bob and Sam were involved in a murder that took place a week prior. So the district attorney puts Bob and Sam into separate rooms and offers them both the same deal.

• If you both keep quite, you both get 1 year in prison for selling drugs.
• If one of you rats out the other for the murder and the other stays quite, the confessor will go free and the other will get life imprisonment.
• If you both rat each other out, you will both get 10 years in prison.

This scenario is called the prisoner’s dilemma and though it may seem like the obvious solution is for both Bob and Sam to stay quite, in reality both of them acting rationally will lead to a sub-optimal outcome. But we will get back to this.

## Investment Theory #9: Buffett’s 1964 Letter

In 1956, Warren Buffett concluded his work for Benjamin Graham and returned to Omaha, where he started an investment partnership. This partnership was formed with seven limited partners, made up of family and friends, contributing \$105,000, and Warren Buffet contributing \$100. Over time it grew.

This post continues my series about that partnership. The goal is to gain some insight into one of the most successful investment vehicles in modern history.

Links to past years can be found here: 1957, 1958, 1959, 1960, 1961, 1962, 1963

## Natural Science #9: Critical Mass

Imagine a cloud of gas floating in space. Over centuries, the cloud collapses under its own gravity and what happens next depends on how much matter was available. In one case, we might end up with a Jupiter or Saturn like ball of gas floating around. Given a bit more matter, we end up with a brown dwarf – a sort of failed star. But at some point, adding a bit more matter causes a drastically different outcome. A thermonuclear reaction lights up the sky.

The amount of matter needed to form that star is called its critical mass and it’s the subject of today’s post.