Previewing Your Trials
Experiments Surveys & forms
The **previewer** lets you run through your trial file in real time, one trial at a time, directly from the editor, without publishing the experiment or collecting data.Launching the previewer
Section titled “Launching the previewer”Open your experiment in the editor and click the Preview button. The previewer opens in a dedicated panel showing your trials exactly as participants would see them.
What the previewer shows
Section titled “What the previewer shows”- Stimuli in their configured format and position
- Response widgets (buttons, keyboard hits, sliders, etc.)
- Feedback text
- Fixation crosses, trial text, and other visual overlays
- Instructions and form trials
- Timer displays
The previewer reserves a 1280 × 740 px area to represent the participant’s screen. Elements outside this area may be cropped or repositioned at runtime.
Limitations
Section titled “Limitations”The previewer is intentionally simplified. Some features that appear at runtime are not active in the previewer:
| Feature | Previewer behaviour |
|---|---|
| Randomisation | Trials appear in file order |
subjectGroup | No group assignment; all rows shown |
| Breaks | Not inserted |
| Timers | May behave differently |
| Script column | May differ from runtime execution |
| Start screens | Not shown |
| Cross-trial audio | Audio from a previous trial does not continue |
Iterating quickly
Section titled “Iterating quickly”Use the previewer to check:
- Stimuli appear at the correct size and position.
- Response options and layout look right.
- Feedback text displays correctly.
- Instructions are readable.
Make edits in the trial file and reload the previewer to see changes immediately.
Next steps
Section titled “Next steps”- Create Your First Experiment: publish and run a live session
- Timing Parameters: verify timing looks right in context
- Define and Position Stimuli: adjust stimulus layout