We all know shortcuts like this:

Photo: Jan-Dirk van der Burg (olifantenpaadjes.nl)

Trails of this sort go by various names. In a photo album devoted entirely to the subject, the Dutch photographer Jan-Dirk van der Burg has coined (or at least popularized) the term "elephant trail" (olifantenpaadje). Wikipedia adopts the more sensuous "desire path". And, of course, there is the simple "shortcut". But regardless the name, it is an intriguing phenomenon. Because these trails are shortcuts, to be sure, but usually not quite the shortest path.

Photo: Jan-Dirk van der Burg (olifantenpaadjes.nl)

But why? If you're going to leave the sidewalk anyway, why not head straight to wherever you need to go? Why the little curve, the minor inefficiency? Surely not to please the likes of van der Burg, who revel in their shape and form.

Photo: Jan-Dirk van der Burg (olifantenpaadjes.nl)

Surprisingly enough, desire paths can be modeled fairly easily. Helding and colleagues have proposed a model in which they are the result of only two opposing "social forces": The tendency to take the shortest path (i.e., a straight line) and the tendency to take the most comfortable path.

The crux of the model is the assumption that paths become increasingly more comfortable as people use them. Which is true, of course, because usage smoothens a path by killing off vegetation, etc. Another factor is the social comfort of walking where others have walked before: Most people do not want to be a rogue wanderer …

Right now I'm reading Philip Ball's trilogy on "nature's patterns". In three books (Shapes, Flow and Branches), Ball describes all kinds of patterns, from the black and white stripes on a zebra's coat to the shape of a milk splash. These are quite possibly the best (not too) popular science books that I've read in years, but more about that some other time, perhaps. Right now I want to focus on one thing that I found particularly intriguing: Ball's description of the organized motion of a swarm.

By definition, a swarm consists of a group of individuals. In the case of bees, and arguably in the case of humans as well, these individuals are driven by simple impulses. They react to other individuals in their immediate vicinity, but there is no master plan, and very little in the way of group coordination. And yet, somehow, from this teeming, chaotic mess, organized behavior does arise.

Consider, for example, what happens when a few bees have discovered a potential nest site, or some other place-to-bee. You might expect the few "informed" bees to separate from the swarm, being unable to communicate their find and thus unable to convince the other members of the swarm to follow their lead. Or you might expect the informed bees to be re-absorbed into the chaos of the swarm, quickly forgetting their find. But, surprisingly enough, this doesn't need to happen: A few informed bees can cause an entire swarm to migrate towards a newly discovered …

This afternoon I was eating a sub in the Plymouth harbor, finally enjoying a bit of sun, which we haven't seen much of this summer. I was joined by a seagull chick. It was presumably hoping to score a piece of my sub.

So why share this wholly unremarkable footage with you? The bird sat there for something like 10 minutes (gulls are nothing if not patient and persistent) and after a while it struck me that it didn't appear to look at me (or my sub) much at all. It seemed to be continuously distracted by something to its right or left, even though there was nothing there, at least nothing as interesting as my sub (I imagine). Then it dawned on me that, in contrast to appearance, the gull must have been looking at me all the time, but with different parts of its eye!

As you probably know, we see only a small part of our surroundings with high resolution and in color. This is the part that falls onto our fovea, a small, extra dense part of the retina. Foveal vision corresponds to about the size of a thumb at arm's length.

Yet we feel as though we have a complete and full-color perception of our entire visual field. In large part, this is because our eyes are mobile: If we think about something, we immediately look at it (bring it into foveal vision) to get a crisp view of the object in question.

So what …

QuiEdit, a full-screen text editor, is the most recent addition to the cogsci software family. I initially developed it for personal use, to write blog posts and such. Like most people, I'm easily distracted when I'm behind a computer (checking email, visiting news sites, etc.). I find that a full-screen text editor really helps when you want to get some writing done. Plus it's kind of pretty, I think, and if you disagree you can easily create your own theme.

Get it here!

As you probably know, brains of humans and other vertebrates consist of two halves, called hemispheres. By and large, both hemispheres carry out the same functions, but they are not identical. The best known asymmetry between the two hemispheres is the lateralization of language: The left hemisphere is dominant when it comes to language. Another obvious example is handedness: The right hand is primarily controlled by the left hemisphere, and vice versa, so handedness reflects a hemispheric specialization in the control of hand movements. Again, the left hemisphere is usually dominant.

The list goes on and on. Everywhere you look there are differences between left and right, which can often be traced back to asymmetries between the left and right hemispheres. Some differences, such as handedness, are obvious, some are subtle. And some are rather cute.

A while back I read a paper by Giorgio Vallortigara, one of the experts on lateralization, in which he made "a stroll through animals' left and right perceptual worlds." One figure in particular stuck in my mind:

So what are we looking at here? Vallortigara and colleagues investigated the predatory behavior of toads using the "worm test". They suspended worms, which toads enjoy very much, from a thread, and slowly brought the worms into the toads' field of view. Sometimes the worms entered the toads' visual field from the left, and sometimes from the right.

What the graph shows is that the direction from which the worm enters the toad's visual field makes a …