You are, of course, familiar with the five classic senses: vision, hearing, smell, taste and touch. But when you take an elevator you can readily feel that this list is incomplete. The queezy sensation that you get in an elevator is largely due to our vestibular system, which provides us with a sense for balance and acceleration. We also have relatively distinct senses for pain, temperature, various aspects of our internal organs (interoception) and the position of our body (proprioception). But even more interesting, I think, are those senses that are completely alien to us, specialized senses that are found only in a few species of animal.

The philosopher Thomas Nagel famously wondered what it's like to be a bat (Nagel, 1974). Although being a bat must be very different from being human in a lot of ways, Nagel referred specifically to the bat's sense of echolocation, which, he felt, is so different from anything that we can experience that we can only guess how a bat perceives the world. And he has a point. Unlike nocturnal birds, which simply have very sensitive eyesight, bats listen to the echoes of their screams (too high for us to hear) to navigate through the dark. The idea behind echolocation is pretty simple: The delay between the scream and the echo tells the bat how far away an obstacle is. If the echo is heard first with the left ear, the object is on the left. And more subtle clues, such as how …

If you rank animals by intelligence, you get a nice, orderly progression (leaving aside the question of what intelligence really is, assuming that I know it when I see it). Invertebrates show little intelligence to speak of, with the exception of arthropods, such as bees, cockroaches and spiders, who exhibit remarkably flexible behavior. Still, remarkable though they may be, they are not as smart as amphibians, fish and reptiles, who are, in turn, not as smart as birds. And at the top of the IQ-chain, of course, we find ourselves, the mammals.

But then there is the octopus, the nerdy cousin of the snail. Octopuses [1] are the only animals I can think of that are fairly intelligent, but are in no way part of the evolutionary axis-of-intelligence formed by the vertebrates. They have a kind of weird, alien intelligence, which is why I think the octopus is the single most fascinating species of animal. (I regret to say that I've never seen one in real life, because all the zoos that I've visited either did not have an octopus or it's aquarium was mysteriously vacant, as cages and aquariums in zoos tend to be.)

Let me give you some numbers, mostly taken from Hochner's delightfully accessible review (2008). An octopus has about 50,000 times as many neurons (brain cells) as a garden snail, which, like the octopus, is a mollusc (molluscs form a rather large phylum, but still). This may not sound terribly impressive, because 50,000 times …

Daniel Schreij reports that he's running OpenSesame, the open-source experiment builder, on Mac OS. Screenshot or it didn't happen (click for full version):

I'm very excited about this! The installation procedure appears to be quite daunting, but at least we know that it works, which brings the goal of providing a user-friendly Mac OS package that much closer. As soon as we have compiled a decent installation tutorial (for the tech-savvy Mac users), it will be posted here, so stay tuned.

More screenshots (click for full version):

Thanks Daniel!

A few days ago, a paper was posted at the arXiv, in which the authors looked at where the top 10% cited scientific papers come from. The distribution is not terribly surprising: Most papers come from Europe, North America and Japan, followed by Singapore, Hong Kong and Australia. But, looking at the maps, you notice a few interesting things. If you compare the maps for Physics, Chemistry and Psychology, you see that the US is dominant in Psychology, but less so in the exact sciences. This is even more apparent for Canada: Most of the green dots on the Psychology map are not even present on the Chemistry map. In Europe the difference between Psychology and the exact sciences doesn't appear to be as pronounced, and in Singapore and Hong Kong it's the other way around.

Image: Citation map for Psychology [source]

References

In Python you can choose whether you want to indent your code using spaces or tabs. However, mixing the two can cause problems. Therefore, I made a simple Python script to fix mixed indentation.

Download: fixindent.

Let's say that you want to change all tab-indents to space-indents (4 spaces wide).

fixindent -i my_input_script.py -s -w 4 -o my_output_script.py

Or, conversely, change all space-indents (8 spaces wide) into tabs. You also want to clean-up extraneous white-space etc. from the line-endings (-c):

fixindent -i my_input_script.py -t -w 8 -c -o my_output_script.py

You can also use pipelines (under Linux at least):

cat my_input_script.py | fixindent -t -c > my_output_script.py