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Intro Bio Psy
Introducing OpenSesame: A Graphical, Open-Source Experiment Builder
Update Nov 30, 2010: OpenSesame has been released and can be found here!

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 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” or the “cue_right” display is shown.

The sequence item (click here for the full size version)

In the screenshot below you can see a “loop” item. A loop item repeatedly runs another item, using different values for the variables each time. A typical use for a loop is to create a block of trials. For example, in the screenshot below, the loop item runs the trial sequence four times. In other words, this loop corresponds to a block of four trials.

The loop item (click here for the full size version)

One of the really cool features of OpenSesame is that you can easily draw stimulus displays, using the “sketchpad” item.

The sketchpad item (click here for the full size version)

And this is how the sketchpad item looks under Windows XP. (Actually, this screenshot is of a slightly newer version than the screenshots above, see the update of Nov 24.)

The sketchpad item under Windows XP (click here for full size version)

Well, I hope you're as excited about OpenSesame as I am! I will put a first version online, as soon as I've smoothed some of the roughest edges.