I spent the past few days trying to photograph very small things. I recently bought a camera, and—like any amateur photographer—quickly discovered that close-ups look amazing. But there's only so many close-ups of bees and flowers you can take before it gets old. So I became hungry for even more extreme close-ups. And because I'm not one to exercise restraint, I bought a camera extension for getting really, really close to your model—which consequently can be really, really tiny.

In principle, I can now take close-ups of very, very small things. In practice, I rarely manage, because this requires perfect lighting, a completely stable image, and some idea of what you're doing. (And probably an even better camera.)

But I managed to take a few semi-decent photos. Not BBC-nature-documentary quality. But they got me thinking.

The creatures in the photos are, I think, different kinds of aphids, all less than a millimeter long (except the winged one below, which was bit larger). To the naked eye, they look like slowly moving motes of dust.

To give you some idea of how tiny these creatures are, here's a clumsy aphid who got stuck on a hair while traversing the mountainous ridges of my index.

My best guesstimate is that their brains are less than one hundred micrometers in size, and consist of about 100,000 neurons. (Which may seem like a lot, but the human brain consists of about 100 billion neurons, or a million times more.)

But …

Update: The Baws Factor described in this post is now available in JASP >= 0.8.2.0 as "Inclusion Bayes Factor bases on matched models". So you don't have to calculate it by hand anymore!

JASP is a free statistics program developed by the group of Eric-Jan Wagenmakers at the University of Amsterdam. JASP is great for doing traditional null hypothesis testing: the kind of statistics that gives you p values.

But JASP is not a traditional program. It's a program with a mission. And its mission is to convince scientists to do Bayesian Statistics: the kind of statistics that gives you Bayes Factors.

A lot has been been written about Bayesian statistics, and much of that by people more knowledgeable than me. So I'll stick to a basic description of what a Bayes Factor is. And then I'll dive right into how you can apply this knowledge to a specific, but very common, kind of statistical test: a Repeated Measures Analysis of Variance, often simply called a Repeated Measures.

For this post, I'll assume that you know what a Repeated Measures is.

What's a Bayes Factor?

A Bayes Factor reflects how likely data is to arise from one model, compared to another model. Typically, one of the models is the null model (H0): a model that predicts that your data is purely random noise. The other model then typically has one or more effects in it, so it's (one of) the alternative hypotheses that you want to test (HA …

George Orwell, best known for his satiric novel about Donald Trump, famously remarked that writing an exclamation point is like laughing at your own joke. Little did he know that, roughly a century later, there would be a universally accepted form of punctuation that allows writers to—quite literally—laugh at their own jokes: the smiley, or emoticon ;-)

I use smileys all the time, even in professional communication. But many things about them bother me. Here's one question, which I'm sure you've struggled with as well: Is a smiley a sentence-ending punctuation mark? That is, does a smiley replace a period, question mark, or exclamation point? And if not, should it come before or after the period, question mark, or exclamation point? In other words, which of the following is correct?

• How are you :-)
• How are you? :-)
• How are you :-) ?

I would go with the first option; the others just look too awful. And "how are you" is not really a question anyway. But reasonable people have been known to disagree on this. It's an important issue though, especially in professional communication, where you want to show that you know how to use smileys properly.

And then there's the thorny issue of smiley inflation, or smilflation: Once you've used a smiley once, you have to keep using them. If not, you're making a point, and a pretty harsh one too. Just look:

• [Ariane] How are you :-)
• [Justin] Great :-D Will I see you tonight?
• [Ariane] Sure.

Ouch. Ariane would have …

Almost fifty years ago, Daniel Kahneman and Amos Tversky conducted their seminal studies on economic decision making, for which Kahneman later won the Nobel prize in economics. Their main message was simple: When it comes to matters of money, people make irrational choices based on gut feelings and intuitions; and these choices are not always in their own best interests.

We now live in the aftermath of the European debt crisis. The core of the eurocrisis was that several European member states were no longer able to finance their government debt; that is, countries like Greece (for whom the crisis is still far from over) had borrowed so much money, mostly from other European member states, that they could no longer pay the interest on these debts.

The way that the European Union (EU) has responded to the eurocrisis is a great example of the irrational economic decisions that Kahneman and Tversky demonstrated fifty years earlier. But on a massive scale—whereas Kahneman and Tversky studied the behavior of individuals, the eurocrisis showed how even economic decisions that affect an entire continent are based on gut feelings and flawed intuitions.

I'm not an economist. And I won't pretend to understand all the factors that played a role in the eurocrisis. But I do think it's useful to look at the eurocrisis with a few basic principles from psychology and economics in mind¹. My goal here is to, by doing so, provide a coherent (though obviously very incomplete) answer to …

As I wrote two days ago, the European Society for Cognitive Psychology (ESCOP) will launch a new open-access journal. What exactly this journal will look like—and what it will be called—is still up in the air. Therefore, Candice Morey, the future editor in chief, asked the community what they would like to see in the new journal.

In this video blog, I discuss some of the ideas that were offered, and provide some background to, and explanation of, the complex issues involved.