Stimulus presentation error


I had a paradigm working on a old MacBook in SuperLab 4.5. However, when I tried to use it on a newer MacBook there were errors. On the new MacBook the program doesn’t present certain stimuli and when I attempt to click on them in the main SuperLab window to get a preview I get an error saying “Unable to open stimulus file. The file could not be read”. The program also gets to a certain point (after skipping various images) and crashes with the following error “This file is not supported by the selected presenter”. The files are in the right folder and the files that are skipped in SuperLab can be opened with a standard image previewer outside SuperLab. The image type ‘.pct’. Here is some technical information on the two computers:

Newer MacBook Pro
• Processor 2.3 GHz Intel Core i5
• Memory 4 GB 1333 MHz DDR3
• Graphics Intel HD Graphic 3000 384 MB
• Serial Number C02GH198DRJJ
• Software OS X 10.9.5 (13F34)

Older mac
• Processor Intel Core Duo 1.83 GHz
• Memory 2 GB 667 MHz
• Serial Number 4H6351P2U9D
• Software OS X 10.5.8 (9L31a)

Hope you can help,


It is difficult to tell what’s going on without seeing the experiment. Can you post it as an Experiment Package (from SuperLab’s File menu, click on Create an Experiment Package).

A SuperLab developer just tried using a sample PCT file with SuperLab 4.5 and SuperLab 5, both on a 10.9 computer – and everything worked fine. So the problem might be specific to certain files.

The PCT file format, also known as the Mac PICT format, was introduced with the original Mac in 1984 and has been deprecated by Apple when Mac OS X was introduced in 2001. Not many programs still support it. It would make sense to consider using a different file format.

Experiment package

Hi Hisham,

I’ve attached the Experiment package (in both formats).

We would really like to use a different file format so we can start using the experiment on a PC rather than a mac. However, since we are new to Superlab we don’t know how to efficiently modify the script. The only method we know would be to manually go through each image event one at a time and modify the file extension. There are a lot of image events in the experiment so this would be highly time consuming. Is there a way to do this more quickly?

CONTR UP faces A_orig.tgz (5.59 MB)

CONTR UP faces (5.59 MB)

I tried using Mac OS’ Preview app, but to my surprise, it allows conversion only to a PDF. I was even more surprised when neither Acorn nor Pixelmator were able to open the files.

Finally, I purchased GraphicConverter 9. It was a batch conversion feature and can open file formats from companies that are no longer even around, e.g. Sun Microsystems. :slight_smile: The converted files are attached.

Converted (11.8 MB)

Hi Hisham,

Thank you for converting the image files. Is there a quick way to modify the SuperLab procedure so that it looks for .jpg files rather than .pct? I would rather not have to go through each event and change the file extension manually.



Replacing all the PCT files with JPG ones is a lot easier when using stimulus lists. (Version 5 places ever more emphasis on lists.)

I took a closer look at the experiment. It looks like at one point, someone in your lab clicked on the Experiment menu and chose Expand Events That Use Lists. I can tell from all the event names that are followed by a file name, e.g. “SNAP Adapt Exp 50 Stim 1 (1, 1912_-70.pct)”.

This feature is useful when the intention is to see how SuperLab will expand a list and use it at run-time, but in most cases the expanded experiment should not be further saved and edited. Unfortunately, at this point you will need to change the files names for each event. In the Event Editor, make sure to use the OK, Next button (instead of just OK) to edit faster.