I’m typing this blog on a Raspberry Pi, a £25 / €30 / $40 mini computer that is literally the size of a credit card.

The Pi is an adorable machine (if you’re into that kind of stuff): Just a small printboard with connectors for a monitor, mouse, keyboard, and an ethernet cable. The system boots from an SD card, so there is no hard disk. There is a choice of Linux-based operating systems, the most commonly used being Raspbian, a Debian spin-off that has been optimized for the Pi. This is also what I installed. And in case you’re wondering: I didn’t open the Pi up – It just doesn’t come with a casing!

Because the Pi is extremely cheap, some people have wondered whether it could be used to equip low-budget psychology labs. This is also how I came into the possession of this diminutive cutie: It’s a gift from Clayton, who wondered how well OpenSesame would fare on the Pi. Thanks Clayton!

If you promise to keep reading, I’ll give you the answer now: Moderately well, with a few caveats.

Snappiness, OpenGL, and v-sync

The operating system on the Pi does not support OpenGL, which is the library used for hardware-accelerated graphics by OpenSesame (or actually by Expyriment and PsychoPy, which are used by OpenSesame). This is a shame, because the Pi comes with a decent graphics unit, which is now essentially unused. However, OpenSesame’s non-hardware-accelerated back-end (legacy, which is PyGame based …

Based on (critical) responses that I received, and discussions that I had after this post, I have added some footnotes to elaborate on certain aspects. The main criticisms are that pre-registration is not necessarily as rigid as I depict it to be (which may be true), and that questioning statistical guidelines is dangerous (which is certainly true, but also a moralistic fallacy: something can be correct and dangerous to say at the same time). Also, see my (sort of) follow-up post The Black Swan and NeuroSkeptic’s response.

In response to the many recent cases of scientific fraud, a debate has ignited about how science can be made more transparent, and how some of the public trust can be regained. Suggestions include …

An evil scientist.

• making all research data publicly available, not just the summarized results.
• making all scientific papers publicly available (i.e. open access).
• investing more time in replicating results, those of others as well as your own (e.g., the reproducibility project).
• and pre-registering all studies.

A slightly mysterious, but influential voice in this debate is Neuroskeptic. In a recent post, Neuroskeptic interviews Jona Sassenhagen, a neurolinguist from the University of Marburg, who decided to pre-register his EEG study. So what does it mean to pre-register a study, and why would anyone do this?

The idea behind pre-registration is simple: Before you conduct your experiment, you publicly list exactly what kind of experiment you are going to conduct, how many participants you will test, and what the …

In the video below, you see Pac-man being chased by a ghost (again)¹. In the first part of the video, the maze scrolls so that Pac-man stays in the center of the screen (side-scroller perspective). In the second part, the maze stays put and Pac-man moves around (static perspective). Both perspectives are used in video games. The side-scroller perspective is used in many older platform games, such as Super Mario Bros, and is in many respects similar to the first-person perspective used in most action games today. The static perspective is used mostly in simple games and very old games, such as Snake and the original Pac-man.

So both perspectives offer perfectly acceptable gameplay. But the difference in your ability to detect changes is dramatic!

With the static perspective, you can see quite clearly that the maze is changing all the time: Except for a few tiles around Pac-man, the whole maze is randomly re-generated with each frame. However, with the side-scroller perspective these changes are much less noticeable, to the point that you may have failed to notice them at all, at least for a while.

So why does the perspective make such a big difference?

You might think that with the side-scroller perspective, there is already quite a lot of change going on, because the maze slides across the screen. The changing structure might simply get lost in the chaos. In contrast, with the static perspective, the maze structure is the only thing that changes, and is …

In the video below, you see an animation of the classic video-game Pac-man ¹. But there is something weird about Pac-man. Can you spot what it is? (For the best effect, play the video in full-screen!)

In fact, as you probably noticed after a while, Pac-man is not doing anything weird at all. It’s the maze that is continuously changing. And not just a wall being added or removed here and there! The whole maze, with the exception of the tiles around Pac-man, is completely randomized with every new frame.

How can it be so easy to miss these large changes that are happening right in front of your eyes?

This video is a somewhat unusual demonstration of a classic phenomenon called change blindness, which was first described by Ronald Rensink, Kevin O’Regan, and James Clark. A typical change blindness experiment is similar to a “spot the differences” game, in which two slightly different images are presented side by side, and you have to, well, spot the differences. This can be very difficult!

Source: Wikimedia Commons

But spotting differences becomes very easy when the same two images are presented one after another at the same location. Now differences correspond to unique changes in the image. These unique changes grab your attention, and therefore really “pop out”.

Source: Wikimedia Commons

However, by adding a blank in between the alternating images, the differences again become difficult to detect. The reason is that, because of the blank, the whole image changes …

Over the past month I ran a small poll on the OpenSesame website about the attitude of researchers towards open access (OA) in academic publishing.

I received 767 responses, where each question was answered only once per IP address. Questions appeared in random order, and the order of the answers was randomized as well. The usual caveat applies, though: Because I ran the poll on the OpenSesame page, most respondents are presumably early-career experimental psychologists, and not representative of the ‘average’ scientist. Nevertheless, I think it’s interesting to see how this particular segment of the research population feels about OA.

So here we go.

Let’s first take a look at the general attitude towards OA. Clearly, as you can see in the figure below, respondents overwhelmingly perceive OA as a good thing. A minority indicates that they are not too interested in the matter, and no-one expresses an outright dislike of OA.

Principles are one thing, but of course what really matters is what people will do in practice. Most respondents indicate that they are likely to submit to an OA journal. However, relatively few indicate that they have actually done so in the past, despite the fact that some well known OA journals (notably PLoS ONE) have been around for years. But then again, many respondents are probably early career academics with few publications on their name.

I think it’s also interesting to consider the reasons that people might have for (not) submitting to an OA …