I like to write: blogs, papers, mediocre bits of fiction that never see the light of day, and even forum discussions. Each of these writings poses its own challenges, and requires its own style. When writing a blog, what is a good opening sentence? (Here I dived right in with "I like to write." Is that too blunt?) What's an acceptable length for a blog, given people's limited attention spans on the internet? (This blog is probably too long.) When to use, and when to avoid, parenthetical phrases? (Avoid, avoid!) When writing a scientific paper, how do you let the introduction flow naturally into the research question? When answering a technical question on a forum, how do you make sure that someone who is already struggling understands your answer?

And, in all cases, how do you avoid mistakes, and express yourself as clearly as possible?

Writing isn't easy, but it's not magic either. Below, in no particular order, are six books that I've personally found very useful in developing my own writing.

1. The Elements of Style

Let's start with a classic: The Elements of Style, by Strunk and White. This 'little book', as William Strunk Jr. called it, has an interesting history. Strunk was an English professor at Cornell University, and privately printed the first version of The Elements for his students. This was around 1918. One of his students was E. B. White.

The collaboration between Strunk and White started only in 1957, a decade after Strunk's death …

Try this little experiment:

• Look at yourself in the mirror from a distance of about 20 cm.
• Alternately look at your left and right eye.

Not much to see, is there? And that's exactly it: You don't see your eyes moving! Yet eye movements are clearly visible. You can verify this with a variation on the same experiment:

• Look at yourself in the front-facing camera of a phone (or any webcam).
• Again, alternately look at your left and right eye.

Now you clearly see that your eyes move, in small jerky movements called saccades. So what's the difference? Why can you see your eyes move in a webcam, but not a mirror?

When one does the second experiment, it is imperative that one duckfaces. (Source)

The answer is that your phone's camera shows things with a slight delay; therefore, you see your eyes move only after they have already stopped moving. In contrast, a mirror has no delay; therefore, to see your eyes move in a mirror, you have to see while your eyes move. And you usually can't—a phenomenon that is often called saccadic suppression. (Because vision is suppressed during saccades.)

An intuitively attractive theory is that saccadic suppression prevents you from seeing a dizzying movement of the world whenever your eyes move. The idea is simple: The eye is a camera, and when a camera moves too rapidly, the viewer gets dizzy. (Think of found-footage movies, which are recorded with a hand-held camera, preferably while the lead …

During my bachelors in cognitive neuropsychology, we often looked at case studies in class. We might be given descriptions of patients with particular symptoms, and be asked to diagnose these patients. During these classes, our professor would often refer to Oliver Sacks' famous compilation of case studies, The Man Who Mistook His Wife for a Hat. From this moment on, Sacks was, to me, the face of neuropsychology. (Our professor often implied that he and 'Oliver' were close friends. I've always wondered whether this was true; our professor was a boastful man, and he's not mentioned anywhere in On the Move.)

But aside from a few extracts from Hat (Sacks has a one-word title for all of his books), I never read anything by Sacks until midway through my PhD, when I picked up The Island of the Colorblind. In the first story of Island (there are two), Sacks describes his visit to an isolated island where about 10% of the inhabitants are fully colorblind. Sacks set out to investigate this peculiar prevalence of full colorblindness, which, unlike red-green colorblindness, is very rare. In the second story of Island, Sacks describes another isolated island community, this time with a more serious problem: many people in this community develop a neurodegenerative disease that leads to Parkinson-like symptoms and crippling disability. Again, Sacks tries to get to the bottom of this medical mystery. (Spoiler alert: Neither story is solved.)

While reading Island, I fell in love with Sacks' writing. The way he …

The Best Illusion of the Year Contest took place last week. As always, there were some cool, new illusions among the finalists—a feast for illusion-afficionados like myself. I particularly like the Honeycomb Illusion by Marco Bertamini and Nicola Bruno. Take a moment to watch (my rendition of) their illusion in its beautiful simplicity (important: for best effect, watch in full screen and HD quality):

This illusion is nothing but a honeycomb grid with little stars (or barbs) at each node. You can see this in close-up on the right.

The stars are clearly visible when you look directly at them. But, and this is where things get interesting, you don't see any stars in the parts of the grid that you don't directly look at. In other words, you get the impression that the little stars follow your eyes around, as you scan the grid with your eyes. I personally find this very compelling.

So what's going on here?

The key to this illusion is that, at any one moment, you only have a clear view of a very small part of the world: the part that falls onto the central part of your retina (the fovea). This part is about the size of your thumb at arm's length. Your peripheral vision, the things that you see from the corner of your eye, is much less sharp, and color blind. This, among other things, is why you move your eyes: You successively direct your central vision at things that …

Ok, stop procrastinating for a moment, and spend your time on something useful. Like finding Boerke in this image:

Boerke, shown at the bottom left, is hiding among his comic-strip buddies. (Source: Stripmuseum Brussels)

While searching for Boerke, you probably scanned the picture in a particular way: You scrutinized small parts of the picture one by one, looking at things that you wouldn't normally look at. Maybe Boerke is behind the ticket counter? (And where's the ticket counter?) No ... Maybe Boerke is climbing the stairs then? No, that's Bobette ... And so on, until you spotted Boerke. (Assuming you have. If not: keep looking!)

But this is not how you usually look at pictures. If you weren't searching for Boerke, you would probably let your eyes wander across the picture, focusing mostly on conspicuous things, like the dinosaur and the rocket.

So, broadly speaking, there are two modes of looking that differ in the amount of effort that you invest: An 'effortful' mode, in which you actively control where your eyes are going, and a 'lazy' mode, in which you let your eyes wander and be drawn to conspicuous things. And, as my colleagues and I have shown in a recent paper (public PDF), it is possible to determine how much effort you invest in your eye movements, simply by monitoring the size of your pupils.

Our experiments were similar to a search-for-Boerke game: Participants searched for a small letter that was hidden somewhere in an image. This was a difficult …