Visual Search Sample Guide

This guide walks you through customizing a Visual Search Task in SightLab VR, where participants locate a target among distractors using gaze-based detection. The script records reaction time per trial and allows for either feature or conjunction search.

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⚙️ Editable Parameters

Customize these settings at the top of the script:

# Enable conjunction search (target shares features with distractors)
CONJUNCTION_SEARCH = False  

# Set how many distractors per trial
NUM_DISTRACTORS = 11

# Total number of trials in the experiment
TRIALS = 3

# Choose your environment
ENVIRONMENT = 'sightlab_resources/environments/RockyCavern.osgb'

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🎯 Target & Distractor Models

By default, this script uses .osgb models for objects:

• If CONJUNCTION_SEARCH is False:
• Target: Red cube
• Distractors: Blue cubes
• If True:
• Target: Red sphere
• Distractors: Red cubes and blue spheres

You can swap models using:

TARGET_OBJECT  = vizfx.addChild('path/to/your_model.osgb', color=viz.RED)

You can also adjust distractors via:

DISTRACTOR_FACTORIES = [
    lambda: vizfx.addChild('your_model_path.osgb', color=viz.BLUE)
]

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🗺 Object Placement Settings

Objects spawn randomly in a 3D volume defined by:

X_RANGE = (-2.0, 2.0)   # left/right
Y_RANGE = (1.2, 2.0)    # up/down
Z_RANGE = (-2.0, 3.0)   # forward/back
MIN_DISTANCE = 0.5      # minimum distance between objects

This ensures spatial separation between target and distractors.

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✅ Gaze-Based Detection

Gaze is automatically tracked on the TargetCube and distractors. The trial ends once the participant looks at the target long enough.

sightlab.addSceneObject('TargetCube', target, gaze=True)

Gaze events are handled with:

def gazeOnTarget(e):
    if e.object == sightlab.sceneObjects[GAZE_OBJECTS]['TargetCube']:
        # Save reaction time and end trial

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🔁 Trial Flow

The script sets up trials like this:

1. Show instructions: "Find the red cube!" (customizable).
2. Wait for trigger press.
3. Randomly place objects.
4. Wait for gaze detection on the target.
5. Log reaction time.
6. End trial.

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🧪 Output & Summary Data

After each trial, the time to locate the target is saved:

sightlab.setExperimentSummaryData('Time to Find Target', time_to_find_target)

SightLab automatically logs this to CSV under your project’s data folder.

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🧱 Extending It

You can expand this experiment in several ways:

• Add target-absent trials
• Vary the number or type of distractors
• Include a rating scale after trials (see SightLab's showRatings() in the rating scale doc)
• Use sightlab.showInstructions() for multi-step instructions

Visualizations

Use the Session Replay to replay gaze paths, walk paths, heatmaps and more using SightLab’s built-in tools.

Biopac Integration**

Send markers using:

sightlab = sl.SightLab(gui=False, biopac = True)

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