The Heritability of Everything

The gold standard in heritability estimates is the twin study, which involves looking at identical and fraternal twins, raised together or apart. This allows the cleanest test of decomposing the variance in observed traits into genetics, shared environment (factors equally affecting all children raised together), and non-shared environment (everything else, including random noise) contributions.

Generally it is assumed that the effect of parenting is equated with the shared environment, though there is clear evidence that parenting can differ substantially between siblings of the same parents and account for a significant fraction of non-shared environment, and the shared environment by definition also captures e.g. the neighborhood in which you grow up. Generally there are many caveats to apply to heritability estimates, particularly that they are only defined within a given population and may not apply as well in extreme cases, but nonetheless they are our best estimates as to the effects of genetics, and the effect is undeniably large.

An extremely ambitious meta-analysis of all twin studies was published in May 2015, reporting heritability estimates from 2,748 studies featuring over 2 million twin pairs, encompassing virtually every published study to date. The researchers have made a data visualization tool available if you wish to dig down into various aspects of the study, though it’s fairly opaque if you’re not familiar with the field’s jargon.

Across very broad domains of health outcomes, almost everything falls within the 40-60% heritability range, with cancer as a representative example being 46% heritable. Similarly, neurological variables show about 50% heritability (with little shared environment involvement), while cognitive and psychiatric outcomes are similarly heritable, but also have a nearly 20% shared environment component. Social values appeared to be 31% heritable, but shared environment played nearly as big a role at 27% explained. Similarly, social interactions were 32% heritable, with a somewhat smaller shared environment component of 18%.

Drilling down into more specific categories of interest, intellectual functions broadly were highly heritable at 67%, while more specific executive function metrics were 51% heritable with a high 24% shared environment contribution. Mood disorders were highly variable, from bipolar being 68% heritable to depressive episodes being 34% heritable. Height and weight showed 63% heritability, with relatively large 30% and 20% shared environment contributions respectively. The more specific values and social variables were mostly in line with the overall findings. Tendency towards religion and spirituality was 31% heritable with an even larger 35% shared environment component. Basic interpersonal interactions were similar, with 30% heritability but 36% determined by shared environment.

To summarize, basic variables in terms of intelligence, height, and weight are primarily determined by the genetic contributions. Most health and psychiatric outcomes fell somewhere in the middle, but still showed roughly half of variance explained by genetics. Variables relating to fundamental values (e.g. religion, politics) and social interactions (e.g. emotional intelligence, relationships) were by far the most malleable traits, with roughly equal contributions from genetics and shared environment.

What Has Changed my Political Beliefs

I think it’s safe to say that political beliefs are one of the most sticky types of beliefs we commonly hold. By some measures partisan polarization is at record highs for the modern era (though these figures are also debated). Politics are also beliefs that provoke some of the strongest arguments between differing viewpoints, and the strongest consolidation among shared viewpoints. Eliezer warned us to be particularly careful when grappling with these ideas.

But, as good rationalists, all of our beliefs should be subject to updating upon receiving further information – and when I look at my political beliefs over the years, I see that they have indeed changed, in some ways massively, in other ways slow and subtly. I thought it would be an interesting to lay out what the drivers of these changes were, as a case study in the art of changing one’s mind.

[Read more…]

Understanding Body Language, Touch, and Appearance

When it came to understanding body language, fashion, all of that kind of stuff, I used to be a typical clueless nerd. I didn’t perceive it, and I didn’t think it really mattered.

I know better now.

It matters. A lot.

Over the years I have seen a lot of objections to learning to perceive this kind of thing on a conscious level – but notably these objections tend to come from people who already know how to do it! For those of us who never learned how to perceive these things by default, there is little choice but to go through the usual conscious incompetence route at first, and I wholeheartedly support any geeks who want to learn how to get better at the things that everyone else already does.

To that end, I have written up notes on body language, touch, and appearance, which systematize most of what I know about these important social variables, and I want to make them available to anyone who wishes to learn this stuff. It can be a challenging and even overwhelming road at first, but I think it’s an incredibly important life skill. Remember that social interaction is a positive sum game. You can have increasing social success and other people will find you more fun to be around!

[Read more…]

How to Build a Tribe

It is important to preface this entire document by saying that I had very specific objectives for creating a tribe. In particular, I wanted a group that was emotionally vulnerable with each other, who are reacting in real time to each other’s responses, where we create a safe space to say and feel and process anything. If you’re looking for something else, only some of this will apply to you. If you share this vision with me, a list of concrete steps to get there from here is below the fold:

[Read more…]

The Comcast Gambit, or How to Save $35 Per Month in Five Minutes

I really didn’t expect that was going to work.

By nature I am pretty conflict averse: I don’t like to directly confront people or get angry or fight for myself. For this reason I will almost never do things like return food at a restaurant, or complain to customer service, or anything like that. I considered this a personal failing – not because I was leaving money on the table, but because I was passing up opportunities because of my own fears. I managed to convince myself that I would rather pay that money to avoid conflict.

Once I developed more of a self-improvement mindset I recognized this as a valuable growth opportunity. Even knowing that this was something I wanted to do wasn’t enough – I had absolutely no practice, I had no idea how to have these kinds of negotiations. It wasn’t until reading some of Ramit Sethi‘s work that I found myself a script. Truthfully, I didn’t need a script, just having it was enough. Just knowing that it was there gave me confidence, something to fall back on.

At this point in my life I’ve done this a handful of times, but was still afraid of getting on the phone with Comcast this afternoon. They had raised my cable bill twice in the last year, once as part of a stepped promotion that I was expecting, the second not so expected. I had seen Ramit talking about this case, and I also read this helpful article that inspired me to call.

Sure enough, his advice worked. I called their hotline, pressed the buttons to disconnect my service (3-2-1-2 if I recall correctly), and they put me through to a representative. That article claims you have to threaten to disconnect to get their best deals – I have no idea if that’s true, but I wanted to maximize my chances. I was appropriately angry, complained about the double rate hike, and told them to disconnect my service. The operator said she would look at what they could offer me, and she gave me another year long promotion at the original rate I paid before, less than half my current bill. She ended with the caveat that this would end in one year and that I should be aware of that, I told her I’d have that conversation in a year from now.

In this case, I managed to cut my bill from $65 down to $30 for a year. That’s $420 for a year, in a phone call that took me just over 5 minutes including the wait time. In terms of an hourly rate that is over $5000/hour. Mind you, this is for cheap internet service. How much could I have saved if I had phone, internet, and cable? How much could I potentially save on other areas of my life? (Ramit definitely recommends getting your APR down on your credit cards, though I pay mine every month anyway.)

I highly recommend trying this for yourself, as either a lifehack or an exercise. Let me know if you have any more tips like this, because I want to try them!

Beyond Rationality

I called this post “Beyond Rationality” because I wanted to move past the unfortunate connotations and bad habits associated with the word “rationality” in our culture. With tongue firmly in cheek, Divia and I often refer to the cluster of ideas I am about to present as post-rationality, and you may well encounter us using that very term. But in truth, I don’t see this philosophy as being opposed to rationality in any way. In fact, quite the opposite – I see this as rationality being properly applied. At the end of my last post, I promised to present you with a model of a rationalist human being. Not an ideally rational agent as described by mathematical equations, but how those abstract representations manifest in a living, breathing person. This is my approach to rationality, my philosophy of life, and why I think that rationality is actually an incredibly powerful meme.

Supremacy of the Instrumental over the Epistemic

In the first post in the series I presented my theory that self-described rationalists most often come to these ideas because of an aesthetic preference for truth. They are drawn to epistemic rationality, and that subsequently defines their relationship to these ideas. I found myself in the exact same boat when I first started out, the notion of systematically honing in on true beliefs was the siren’s call that left me immediately hooked. I had to understand these methods and apply them to my own cognition… and this laid the seeds for the triumph of instrumental rationality. [Read more…]

How to Network Effectively

Networking is a critically important skill. There is a great phrase that you are the average of the five people you spend the most time around. For humans, most of our environment is the social environment. Your ability to interact with others, and who those other people are, is most likely going to be your bottleneck on what you can accomplish in the world. Even skills like programming or engineering, where you’re creating something new in the world, are enabled by the web of social interactions you are embedded in – the greatest product in the world will never be used if it cannot be discovered.

Step One: Have a Goal

[Read more…]

Summary of Nonviolent Communication


Nonviolent Communication is a communication and conflict-resolution process developed by the psychologist Marshall Rosenberg. The book focuses on how to express ourselves in a way that inspires empathy in others, and how to listen to them empathically in turn. This system radically changed my understanding of human interactions, and using these techniques with myself greatly reduced my own level of self-judgment. I highly recommend this book.

[Read more…]

Summary of How to Win Friends and Influence People


How to Win Friends and Influence People is a classic book by Dale Carnegie with a pretty self-explanatory title. I read this book recently, and was surprised to find that it epitomized a lot of the wisdom I had already picked up from a variety of other sources. Note that this summary is from the revised 1981 edition, which removed the sections on writing good business letters and achieving marital satisfaction.

[Read more…]