I'm pleased to announce that development on OpenSesame has started. OpenSesame is a graphical experiment builder. Compared to existing software for creating psychological experiments, OpenSesame has a number of cool extra tricks up its sleeve.

OpenSesame is ...

• … free and open-source.
• … cross-platform. Windows and Linux packages will be provided, but if the required libraries are installed, OpenSesame should also run on Mac OS.
• … an extremely easy way to build experiments using a graphical user interface. You can even draw your stimulus displays using the built-in sketchpad!
• … compatible with Python. This means that you can combine the ease of the graphical interface with the full power of Python scripting.

You can expect a first version of OpenSesame to land in the software section of cogsci.nl in the near future. For now I have a couple of screenshots. So let's take a look! (Click on the screenshots to see the full size images.)

The screenshot below shows a “sequence” item. A sequence runs a number of other items in sequence (obviously). In the example below, the sequence consists of a fixation display, a cue display, a target display, a keyboard response collector, and, finally, a logger item (which logs the response to file). A typical experimental trial, in other words. One of the cool things of the sequence item is that you can use conditional statements. For example, depending on the value of the “cue” variable, either the “cue_left …

A colleague of mine just installed Zotero and he reminded me of a particularly nasty issue that affects Zotero on most modern Linux distributions. I believe it affects at least all recent versions of Ubuntu, Fedora and OpenSUSE. The problem stems from the fact that the Sun implementation of Java has been replaced with the open source OpenJDK kit, which does not play nice with Zotero. The symptoms are confusing error messages when you try to use Zotero from within OpenOffice.

The solution is to remove all OpenJDK packages and install Sun java. In Ubuntu you can do this by opening the Synaptic package manager under System → Administration → Synaptic package manager, searching for openjdk and icedtea and removing all matching packages that you have installed. Next you search for sun and install the following packages: sun-java6-bin, sun-java6-jre and sun-java6-plugin. Next, restart Firefox and OpenOffice and you should be good to go!

Update Jan 3 2011: In order to install Sun java you need to enable the Canonical partner repository in Ubuntu. If it isn't enabled already, you can do so by opening the Synaptic package manager (Menu → System → Administration → Synaptic Package Manager), opening the Software Sources (Menu → Settings → Repositories) and enabling the Canonical Partners repository (Other Software → Canonical Partners).

There are two experiments that you can participate in online, here at cogsci.nl. Both are cognitive psychology classics. Try it, it's kinda fun (for a little while)!

I just analyzed the data from the feature integration experiment, based on the classic study by Treisman and Gelade. In this experiment, you have to indicate whether a red “T” is present in the display. (Btw, you can still participate in the experiment.)

In the “color popout” condition the red “T” is presented among green “T”-s. In the “shape popout” condition, it is presented among red “X”-es. These conditions are relative easy, because the target differs from the other letters (the distractor stimuli) on a single feature. That is, the target is either the only “T” (easy) or the only red object (even easier). According to Treisman and Gelade, you do not need to search the display for the target in these trials—the red "T" just pops out! Therefore, it doesn't really matter how many distractors there are. In the graph, you can see that, indeed, the “search slopes” for the popout conditions are relative flat: People do not respond much slower or make many more errors, if the red “T” is presented among many green “T”-s (large display size), relative to only a few green “T”-s (and analogously for the shape popout).

The situation is radically different for the conjunction condition. In the conjunction condition, the red “T” was presented among green “T”-s, green “X …

Update Nov 16, 2010: If you have trouble getting Zotero/ OpenOffice to work on Linux, please see this post.

If you've ever written a paper or a thesis you will no doubt agree that reference management can be a daunting task. You have to make sure that every reference in the text appears in the reference list, and, conversely, that every item from the reference list actually appears in the text. There are also many style guidelines that you're supposed to adhere to.

For example, according to the publication manual of the American Psychological Association (APA), the first time that you cite a paper you have to list all authors (unless there are more than five authors), like “(Author1, Author2, & Author3, 2010)”. In subsequent citations, you should name only the first author, like “(Author1 et al., 2010)”. In itself, this is a sensible rule, but it means that you have to keep track of where in the text you cite a paper for the first time. This also means that you have to update your citations whenever you shuffle around paragraphs. These are precisely the types of trivialities that you do not want to bother with while writing a manuscript!

Fortunately, there are software packages available that help you manage your references. The most famous of these are BibTeX (which is actually a format used by multiple tools), EndNote (widely used, but proprietary) and Zotero. If you want to cite a paper, you simply tell the reference manager to insert …

In a recent study in Biology Letters, Vahed and colleagues measured the size of testes in a number of bushcricket species. They found that in species with slutty females (i.e., a high level of polyandry), the males have larger testes. Somewhat surprisingly, however, larger testes do not lead to larger ejaculations, but instead to more frequent ejaculations. Clearly, the males are quite promiscuous as well.

Source: Wikimedia Commons

However, the real reason for mentioning this study is that Vahed and colleagues found a particular species of bushcricket, in which the testes account for a whopping 13.8% of the males' total body weight! The most ballsy animal ever found.

References