Emotional Dot-Probe Task (EmoDot)

Field	Value
Name	Emotional Dot-Probe Task (EmoDot)
Version	main (1.0)
URL / Repository	https://github.com/TaskBeacon/EmoDot
Short Description	A task for assessing attentional bias toward emotional facial stimuli
Created By	Zhipeng Cao (zhipeng30@foxmail.com)
Date Updated	2025/06/22
PsyFlow Version	0.1.0
PsychoPy Version	2025.1.1
Modality	Behavior/EEG
Language	Chinese
Voice Name	zh-CN-YunyangNeural

Note

The emotional expression stimulus are not publicly available due to potential copyright issues.

1. Task Overview

The Emotional Dot-Probe (EmoDot) task assesses attentional biases toward emotional stimuli. Participants are briefly shown a pair of face images—one emotional (positive or negative) and one neutral—followed by a target (a white circle) appearing on the left or right side. Participants must quickly respond to the target’s position by pressing a corresponding key. The emotional valence, facial gender, and target location are all experimentally manipulated. The task also incorporates trial-by-trial stimulus randomization from a categorized image pool to ensure balanced and unpredictable face pairings.

2. Task Flow

Block-Level Flow

Step	Description
Load Config	Load task configuration, subject info schema, stimuli, triggers
Collect Subject Info	Capture ID, name, age, gender
Setup Triggers	Initialize trigger sender via serial port
Initialize Window/Input	Set up PsychoPy window and keyboard
Load Stimuli	Build static stimuli (shapes, text, etc.), preload and convert instructions
Load Assets	Retrieve image files from asset folder and organize by category
Initialize Stim Pool	Create randomized per-category pools for sampling stimuli
Show Instructions	Display instruction text and synthesized voice
Loop Over Blocks	Run 3 blocks × 60 trials (with stimulus pairing + response logging)
Show Block Feedback	Display summary (accuracy) after each block
Show Goodbye	Display thank-you message
Save Data	Save full trial data to CSV
Close	Close serial connection and PsychoPy window

Trial-Level Flow

Step	Description
Fixation	Present fixation cross (0.8–1.0s) with trigger
Cue Display	Show pair of face images (left/right) for 0.5s with trigger
Interval	Brief fixation interval (0.4–0.6s)
Target	Show white circle target on left or right; collect response (up to 1.0s)
Response Logging	Record accuracy, RT, and target location

Other Logic

Component	Description
AssetPool	A class that manages condition-specific stimulus pools using shuffle-on-depletion logic
get_stim_list_from_assets()	Scans the assets/ directory for .bmp images and categorizes them by prefix (e.g., HF, SAF)
assign_stim_from_condition()	Given a trial condition string (e.g., PN_F_L), selects appropriate stimuli and target side
Condition Encoding	Each condition encodes emotion pairing (PN, SN, etc.), gender (M/F), and target side (L/R)

These logic components collectively ensure:

• Dynamic, trial-specific face assignment per condition

• Balanced sampling across categories

• Prevention of stimulus repetition until category depletion

• Flexible extensibility for new emotion/gender pairings

3. Configuration Summary

a. Subject Info

Field	Meaning
subject_id	Participant ID (101–999)
subname	Participant name (pinyin)
age	Age (5–60)
gender	Gender (Male/Female)

b. Window Settings

Parameter	Value
size	[1920, 1080]
units	deg
screen	1
bg_color	black
fullscreen	True
monitor_width_cm	59.7
monitor_distance_cm	72

c. Stimuli

Name	Type	Description
fixation	text	White “+” central fixation
left_stim	image	Face image on the left (dynamic)
right_stim	image	Face image on the right (dynamic)
left_target	circle	White circle target (left side)
right_target	circle	White circle target (right side)
block_break	text	Summary screen with accuracy between blocks
instruction_text	textbox	Multi-line instructions on cue-target mapping
good_bye	textbox	Final message post-task

d. Timing

Phase	Duration (s)
fixation	random 0.8–1.0
cue display	0.5
interval	random 0.4–0.6
target	1.0

e. Triggers

Event Type	Example Code
Task Start	98
Task End	99
Block Start/End	198 / 199
Fixation Onset	11–201
Cue Onset	12–202
Target Onset	13–203
Key Press	68
No Response	69

Note: Each condition (e.g., PN_F_L) has unique fixation/cue/target onset and response triggers.

4. Methods (for academic publication)

Participants performed a computerized emotional dot-probe task designed to probe attentional biases toward emotional facial expressions. Each trial began with a fixation cross (0.8–1.0 seconds), followed by a pair of face stimuli (one emotional—positive or negative—and one neutral), presented side by side for 0.5 seconds. After a brief inter-stimulus interval (0.4–0.6 seconds), a target dot appeared on either the left or right side of the screen. Participants were instructed to respond as quickly and accurately as possible by pressing the “F” key for left and “J” for right.

The experimental conditions conterbalanced the emotional content (positive, negative, or neutral), the gender of the faces (male/female), and the target location (left/right). A pool of facial images was pre-organized by emotion and gender categories and dynamically sampled to prevent stimulus repetition. Each image pair was randomly drawn per trial while satisfying the specified emotion/gender constraints.

The experiment consisted of 3 blocks with 60 trials each, totaling 180 trials. Trial types were fully randomized using a blocked condition design. At the end of each block, participants received feedback about their hit rate (i.e., correct target detections).

5. References

MacLeod, C., Mathews, A., & Tata, P. (1986). Attentional bias in emotional disorders. Journal of Abnormal Psychology, 95, 15–20.

Van Rooijen, R., Ploeger, A., & Kret, M. E. (2017). The dot-probe task to measure emotional attention: A suitable measure in comparative studies?. Psychonomic bulletin & review, 24, 1686-1717.

A study that seems worth paying attention to

Xu, I., Passell, E., Strong, R. W., Grinspoon, E., Jung, L., Wilmer, J. B., & Germine, L. T. (2025). No evidence of reliability across 36 variations of the emotional dot-probe task in 9,600 participants. Clinical Psychological Science, 13(2), 261-277.