Emotional Dot-Probe Task – PsyFlow Version

This task implements an emotional dot-probe paradigm to measure attentional bias towards emotional versus neutral stimuli. Participants respond to the location of a target dot that appears after the brief presentation of two face stimuli. The task is built using the PsyFlow framework.

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Task Overview

Participants first view a fixation cross, followed by a brief presentation of a pair of face images (e.g., positive vs. neutral, negative vs. neutral). After a short interval, a small target dot appears on either the left or right side. Participants must quickly indicate the location of the dot by pressing the left or right arrow key.

This task assesses attentional biases toward emotional stimuli and is widely used in studies of anxiety, depression, and emotional regulation.

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Task Flow

Step	Description
Instruction	A textbox (instruction_text) presents task instructions in Chinese. Participant presses the space bar to start.
Fixation	A fixation cross "+" is shown at the center of the screen.
Cue Pair	A pair of face images (left and right) are displayed briefly.
Interval	A short blank screen or fixation is shown after the faces.
Target	A dot appears either on the left or right side; participant responds via arrow keys.
Block Break	After each block, performance feedback is presented and participants rest.
Goodbye	A final thank-you screen ends the session.

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Configuration Summary

All key settings are stored in the config/config.yaml file.

Subject Info (subinfo_fields)

Participants are registered with:

• Subject ID (3-digit number from 101–999)
• Session Name
• Experimenter Name
• Gender (Male or Female)

Localized prompts are available via subinfo_mapping.

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Window Settings (window)

• Resolution: 1920 × 1080
• Units: deg
• Fullscreen: True
• Monitor: testMonitor
• Background color: black

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Stimuli (stimuli)

Stimulus Name	Type	Description
fixation	text	Central fixation cross "+"
left_stim, right_stim	image	Face stimuli dynamically assigned per trial
left_target, right_target	circle	Target dots shown left or right
block_break	text	Mid-task break message
instruction_text	textbox	Task instructions in Chinese
good_bye	textbox	End-of-task thank-you screen

Stimulus images are dynamically assigned based on trial conditions using an asset_pool.

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Timing (timing)

Phase	Duration
Fixation	0.3 seconds
Face Cue	0.5 seconds
Interval	0.4–0.6 seconds (randomized)
Target Response Time	1.2 seconds

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Conditions (task.conditions)

Each condition represents the combination of:

• Emotion pair (Positive-Neutral, Negative-Neutral, Neutral-Neutral)
• Gender of faces (Female, Male)
• Target side (Left, Right)

Example condition codes:

• PN_F_L – Positive (left) / Neutral (right), Female faces, Target Left
• SN_M_R – Negative (left) / Neutral (right), Male faces, Target Right
• etc.

There are 18 conditions in total.

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Triggers (triggers)

Each condition has a full set of triggers:

Event	Trigger Code Example (for PN_F_L)
Fixation Onset	11
Cue Onset	12
Target Onset	13
Key Press	14
No Response	15

General experiment and block onset/end triggers:

• Experiment Start: 98
• Experiment End: 99
• Block Start: 198
• Block End: 199

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Running the Task

python main.py