What is an Interaction Effect?

Introduction Yesterday, Uri Simonsohn published a blog post called “Interactions in Logit Regressions: Why Positive May Mean Negative”. I love Uri’s blog in general, but I was pretty confused by this latest post. I found it very hard to understand exactly what was being claimed in the absence of formal mathematical definitions of the terms […]

Where Predictive Modeling Goes Astray

I recently reread Yarkoni and Westfall’s in-progress paper, “Choosing prediction over explanation in psychology: Lessons from machine learning”. I like this paper even more than I liked their previous paper, but I think a few notes of caution should be raised about the ways in which a transition to predictive modeling could create problems that […]

Quick Review of Matrix Algebra in R

Lately, I’ve been running a series of fMRI experiments on visual perception. In the interests of understanding the underlying properties of the images I’m using as stimuli, I’ve been trying to learn more about the matrix transformations commonly used for image compression and image manipulation. Thankfully, R provides simple-to-use implementations for all of the matrix […]

Some Pitfalls of Object Oriented Programming in R

Yesterday, I wrote a post about implementing setter methods for objects in R. On my way to understanding how to implement these methods correctly, I made a bunch of mistakes. To keep people from wasting their time with these same mistakes, I’m reviewing them here. Mistake One: Naming Conventions Every generic method will search for […]

Coase and Literary Talent among Scientists

There is no reason to suppose that most human beings are engaged in maximizing anything unless it be unhappiness, and even this with incomplete success.1 Why can’t more scientists write like this? I have the sad impression that most scientists view wit and spirit of this sort as signs of intellectual weakness rather than as […]

Hating on Norman Mailer

This assault on Norman Mailer impresses me more the more times I read it. I’m not familiar enough with Mailer to judge its accuracy, but the tone is perfect for my taste: His vulgarity was a more significant factor in his allure than whatever he possessed of high aspiration. The way his most serious ambition […]

Sick Day Achievements

Spending my day at home while being sick has at least one perk: I can catch up with everything on the Internet that I’ve put off reading. After a day of RSS feed reading, I’ve compiled a list of things that I think are awesome and another list of things that I think are awful. […]

Stagger Lee

To know a man, you need only find out how he envisions the story of Stagger Lee.

The Painted Veil

I watched the Painted Veil again tonight. I’m always amazed by the quality of the story and the dialogue: while I understand that it’s an adaptation of a classic novel, I am nevertheless continually astonished that such a good movie should ever have been released. There is just such a wealth of wonderful points about […]

The ISS Surpasses Venus

I think there’s something beautiful about the International Space Station becoming the brightest object in the night sky after the Moon.