Mental Rotation Task
This example implements a mental rotation experiment inspired by the classic study by Shepard & Metzler (1971).
1. Experimental Task
The participant is shown two 2D asymmetrical shapes side-by-side. The task is to determine if the right-hand shape is:
- A rotated version of the left-hand shape (“Same”).
- A mirrored and rotated version of the left-hand shape (“Different”).
Stimuli
- Shapes: Asymmetrical 2D polygons (L-shaped).
- Angles: The right-hand shape is rotated by 0, 40, 80, 120, or 160 degrees relative to the left-hand shape.
- Conditions: “Same” (rotated) vs “Mirrored” (reflected then rotated).
2. Procedure
- Instructions: An initial screen explains the task.
- Fixation: A fixation cross is displayed throughout the experiment (during the 500ms fixation period, stimulus presentation, and inter-trial interval).
- Stimulus: Two shapes appear alongside the central fixation cross. The participant responds as quickly as possible.
- Feedback: Negative auditory feedback is provided for incorrect responses (Buzzer). Correct responses do not trigger a sound.
- Data Logging: Accuracy and Reaction Time (RT) are recorded. Typically, RT increases linearly with the rotation angle for “Same” pairs.
3. Controls
- ‘S’: Press to indicate the shapes are the SAME.
- ‘D’: Press to indicate the shapes are DIFFERENT (mirrored).
- ‘ESC’: Quit the experiment.
4. How to Run
From the Mental-Rotation directory:
go run main.go -d -s [subject_id]
Or from the repository root:
go run examples/Mental-Rotation/main.go -d -s [subject_id]
- -d: Developer mode (windowed display).
- -s: Subject ID (default is 1).
5. Notes on 3D Implementation
The original Shepard & Metzler study used perspective drawings of 3D cube assemblies. This implementation uses 2D polygons as a programmatic proxy. To reproduce the exact 3D stimuli, you can replace the stimuli.Shape calls with stimuli.Picture calls using pre-rendered images of the 3D objects at various rotation angles.
References
- Shepard, R. N., & Metzler, J. (1971). Mental rotation of three-dimensional objects. Science, 171(3972), 701-703.