Fig. 1
The six trial types in the BST for which the participant must sort the shape, but not the color, of the stimulus. Rows show congruent, neutral and incongruent trials; columns show circle versus square stimuli.
Fig. 2
Depiction of the steps used to run the BST via the PEBL Launcher. First (top panel) the BST folder must be selected and opened by clicking twice from within the battery\ folder. Next (bottom panel), the BST.pbl file must be selected, and the test launched using the ‘Run selected script’ button. Other experimental parameters, such as participant code, screen resolution, etc. can be controlled via the launcher.
Fig. 3
Example instruction, stimulus, and completion screens of the Bivalent Shape Task (BST).
Table 1
Files included in the BST package. Image and sound files can be replaced to adapt the task for other purposes.
| Filename | Description |
|---|---|
| BST.pbl | PEBL source code file |
| LICENSE | Copy of GPLv3 |
| BST.pbl.png | Screenshot of test for launcher |
| README.md | Description of test |
| blackcircle.png | Stimulus image |
| blacksquare.png | Stimulus image |
| bluecircle.png | Stimulus image |
| bluesquare.png | Stimulus image |
| redcircle.png | Stimulus image |
| redsquare.png | Stimulus image |
| beep.wav | Auditory feedback for correct trials |
| buzz.wav | Auditory feedback for correct trials |
Table 2
Variables that control basic experimental properties.
| Variable | Values | Impact |
|---|---|---|
| gUseRandom | 0 (not random) or 1 (random) | Each run uses either an identical (0) or unique (1) order. |
| gResponseOffset | 100 | Left/right offset from center of response targets. |
| gResponseY | screenheight/2+150 (default) | Distance, in pixels, from top of screen, of response targets. |
| gResponseTimeLimit | 3000 (default) | How long (in ms) a response must be before trial is aborted. |
| gUseVisualFeedback | 0 (default) or 1 | Always use visual feedback. |
| gUseAudioFeedbackAlways | 0 (default) or 1 | Always use auditory feedback. |
| gUseAudioFeedbackPractice | 0 or 1 (default) | Use auditory feedback during practice trials. |
| numtrials | default is 20 | Baseline number of trials per block. |
| gUseMouse | 0 (default; keyboard) 1 | Determines whether mouse or keyboard should be used for response collection and instructions. |
Fig. 4
Example Report from the BST, showing mean response time (in ms) and accuracy for each of six conditions.