PubMed is a popular search engine for biomedical literature. It has lost a lot of ground to Google Scholar over the past few years, but for a long time it was the go-to scientific search engine for psychologists, neuroscientists, and the likes. And the cool thing is that, unlike Google Scholar, PubMed allows you to write scripts to automatically download enormous amounts of information.

Which is what I did over the weekend: I downloaded information about scientific articles. Names, authors, abstracts (summaries), journal titles, etc. And lots of it. I figured I would eventually get banned for abusing the PubMed service, but I didn't, and the end result is a database containing 257.535 articles published between 1950 and 2010 in 43 academic journals, broadly focused on neuroscience and cognitive psychology [1]. To the extent that PubMed has a complete index, this should include a large proportion of all articles published between those years in those journals.

So that's a lot of data!

I'm planning to write a series of blog posts, each time focusing on a different aspect of this data set. My main aim will be to understand the whole system academic publishing just a little bit better, and to see how it has evolved over the years. All the while keeping in mind, of course, that even these quarter of a million articles reflect just a tiny fraction of the total volume of scientific output. And a biased fraction at that, because the journals have been hand-picked …

I recently stumbled across a great video tutorial for the OpenSesame experiment builder. This video, created by Chris Longmore, shows how to build an experiment in which participants have to judge the gender of a (picture of a) cat. This is kind of goofy, but experiments of this kind have been conducted at least twice. Once by Quinn and colleagues, and once by Longmore himself. And, apparently, people are able to distinguish male cats from female cats. Barely, but still. (You can participate in an online version of the experiment here.)

Here's the video:

And, because I'm sure you're wondering, here are some pictures of cats split by their actual and perceived gender. It seems (to me) that people go largely by colour and size: Big, dark cats look male, whereas slender and lightly coloured cats are perceived as females.

References

The Chicken Head is a dance that was popularized by the video clip to Chingy's Right Thurr, which was a big hit back in 2003.

If you do the Chicken Head well, the flapping of your 'wings' makes you look a bit like a chicken. Another distinctly chicken-like aspect of the dance is that you need to keep your head more or less still, while swinging your body from side to side.

For this post I will elaborate a bit on this last point.

As you can see in the video above, chickens are remarkably good at keeping their head still while their body is moving. They are able to do this when someone else moves their body, as in the video, but also when they move themselves. This is why a chicken's head (or a pigeon's head, as in the video below) bobs back and forth during walking: The chicken keeps its head still with respect to the environment by moving it backwards to compensate for the forwards body movement. This continues until the head cannot move back any further, at which point it rapidly snaps forward, momentarily breaking the otherwise near perfect head stabilization (see note 1 below for a popular myth on head bobbing).

When you think of it, head stabilization is a remarkable feat: The gravitational (or vestibular) sense is required to keep the head up-right, regardless of the body's orientation. And you also need to take into account the position of the body parts relative …

I don't remember when I first saw a video of an octopus's amazing camouflaging abilities, but I know that I've been fascinated ever since.

Its not just the octopus that is a master of disguise, though. Pressured by the unique challenges of marine life, many marine animals have evolved elaborate forms of camouflage. Prime examples of this can be found in the twilight zone, the colloquial term for the oceanic zone that lies a few hundred meters beneath the surface. Because of the three-dimensional nature of their aquatic environment, it is extremely difficult for animals in the twilight zone to camouflage themselves properly: When viewed from below, they need to blend in with the (relatively) bright surface. When viewed from above, they must blend in with the dark ocean floor, or the equally dark depths. A singular form of camouflage will simply not do!

In response to this challenge, many "twilight fish" have evolved multiple, complementary forms of camouflage. To be hidden when viewed from above, they tend to have a darkly pigmented back that avoids standing out against the oceanic darkness below (a in the figure). Another, more ingenious form of camouflage is provided by silvery, reflective sides (b). These function as mirrors that reflect light from the surface, thus providing near invisibility when viewed from below at a slight angle. Obviously, having a dark back or reflective sides offers little protection when viewed from directly below. To be invisible from this angle as well, these fish employ a …

Over the past few months a lot of work has been done on OpenSesame, the graphical experiment builder. And, if all goes well, version 0.25 ("Dashy Darwin") will be released soon! For this release, the focus wasn't on new functionality, but on bug-fixes and adding polish to the user interface. Thanks to a large (and rapidly growing) amount of user feedback, 0.25 is looking to be a great release! Thanks to everybody who helped out, even if just in a small way by dropping a note and/ or giving some constructive comments.

At this point, the pre-release packages are pretty stable, but of course there's always the chance of bugs that have been overlooked. If you have some time to spare (or are starting a new experiment), I would encourage you to try the latest pre-release packages and let me know of your experiences (particularly bad ones). When 0.25 is officially released, you will receive a notification so you can immediately switch to the official, stable version.

Download (0.25-pre13 is the latest pre-release right now):

• [OpenSesame 0.25 has been released, pre-release builds are no longer available]