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 …

Last week, six contestants in a cycling race in Norway were poisoned after drinking laundry detergent. Drinking detergent seems like an exceedingly idiotic thing to do. So how come that six people did this? Well ...

(Source: Twitter)

... Omo Aktiv & Sport really looks like a sports drink.

In the beginning of 2006, there were almost one hundred reports of people being poisoned after drinking Fabuloso, a surface cleaner that promises to make dirty floors shine again. Why? Well ...

... Fabuloso really looks like a soft drink.

The reason that manufacturers make their cleaning products look like food is obvious. People like eating better than cleaning, so a cleaning product is more attractive if it looks edible.

Non-foods that look like foods, and non-drinks that look like drinks, are called food-imitating products. They are recognized as a public health risk by the European Union. If a detergent looks like a drink, someone will drink it. The result is a nasty case of poisoning, which, in rare cases, can be deadly. It's a problem.

The issue of food-imitating products was studied in an interesting, if somewhat quirky, study by Basso and colleagues. This study is not new, but I think it's worth mentioning again after the cycling-race incident in Norway. First, Basso and colleagues reviewed real-life cases of poisoning by food-imitating products. Surprisingly, at least to me, poisoning was not limited to children or elderly, groups that you might expect to make these kinds of mistakes more easily. Rather, there were several reports of …

I'm writing this on my way back from London, where I attended a workshop on publication bias that was organized by the NC3Rs (the British National Center for the Replacement, Refinement, and Reduction of Animals in Research). Publication bias arises when not all scientific studies are published, and when the chance of whether a study is published depends on its outcome. More specifically, studies that show a 'positive' result (e.g. a treatment effect, or something that supports a researcher's hypothesis) are published more often than studies that show a 'negative' result (e.g. no treatment effect, or something that doesn't support a researcher's hypothesis). Publication bias distorts scientific evidence. In most cases, it makes treatments (drugs, therapies, etc.) seem more effective than they are, simply because we only see studies that show positive treatment effects.

Publication bias is increasingly recognized as a severe problem that affects all areas of science. It's not new. It's just that until recently little was done about it. It was therefore great to see this workshop bring researchers, funders, publishers, and people from industry together with the aim of discussing concrete ways of reducing publication bias. In this post I would like to tell you about some of the things that were discussed.

There were many excellent speakers, but I will first highlight the opening talk by Emily Sena. Her talk was partly based on a meta-analysis in which she investigated publication bias in animal research on stroke treatment. Her work nicely shows how …

I recently had a little adventure on the Google Play store, where I publish a few apps. I wanted to share the story with you, because it illustrates the danger of having a single company (Google) that dictates an entire platform (Android) and its app store (Google Play Store).

It's about a game app called Infinite Maze. This is a cute little game that Theo Danes and I created as an entry for the 2014 Best Illusion of the Year Contest. A playable optical illusion! We didn't win, but I'm proud to say that we made the finals.

You can read more about the illusion here, but this post is about a trademark infringement that was filed by Namco against a dozen-or-so apps, including Infinite Maze. Namco is the company behind Pac-man. Their exact allegation was:

this app infringes PAC-MAN in the first game screenshot; PAC-MAN is clearly seen as the game title

Besides punctuation, there is something very wrong with this allegation: It is not true. Sure, Infinite Maze is a labyrinth game, and it's clearly inspired by Pac-man. In the past, I have even referred to it as Infinite Maze of Pac-man. But before uploading it to the Google Play store, I removed all mention of the word 'pac-man' in the game so that I wouldn't violate any trademarks. The word 'pac-man' now only occurs in the app description in the context of 'a pac-man-inspired game'. A phrasing that, as far as I know, doesn't constitute trademark infringement …