Shepard and Meltzer (1971) were looking for empirical evidence to shed some light on the mental imagery debate. Prominant debaters of this debate were Kosslyn with his mental map model and Pylyshyn with a more Fodorian Language of Thought approach. Shepard and Meltzer's experiment and the hundreds of subsequent studies on mental rotation are central elements in the empirical foundations of today's cognitive psychology. (Birch, 1998)
At AUBG, in the winter of 1993, my academic advisor and Philosophy professor, Tony Birch, was working on his PhD thesis along these lines and wanted to replicate Shepard and Meltzer's experiment. He told me that he was looking for someone to write a program to draw and rotate 3-dimensional objects and there I was, enthusiastically jumping in several months of TurboPascal coding. The result was PresentaTHOR
(DOWNLOAD: zip archive of v1.1- 59k:
NOT THOROUGHLY TESTED. MAY CRASH. USE AT YOUR OWN RISK, etc. etc.).
What it does is separated in several modules:
So why didn't we just use some commercial 3D image generator (I already knew Autocad!), for the stimuli and then some commercial experiment-design program (PsyScope had an early version at the time) to run the thing?? Here's why:
As you look at the program, please keep in mind that it was written when most programming and 3D packages (except for high-end graphic workstation software), used a command-line interface or text editors. You may find kinks and usability issues in the menu system I implemented, but I was trying to make the user interface friendlier (part of my work on computer-human interfaces). Also, all data and support files (except for the 2D image snapshots), are ASCII text, so users have the choice of using the interface for editing objects, or simply editing the object file.
Since the name is pretty cumbersome, we informally called this tool PREZ. I'll bring an archive of it online ASAP. Recently, a friend happened to do a similar experiment and I played around with the image output and the image generation interface. It's tough to see the difference on these images, but instead of "guessing" angles, scales and perspectives, like in the old, entry-type interface, now the user can also set an increment and press the arrow keys to adjust the needed parameters of the image: object used, scale, rotation, perspective.
Big THANK YOUs for PresentaTHOR go to:
If people are really interested (interested enough to fund my work on it), or if I get time to work on Prez (yeah, right, keep dreaming, Radu! :), there are some things I'd like to change or add:
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