Flanker Task

Field	Value
Name	Eriksen Flanker Task
Version	v1.2.0
URL / Repository	https://github.com/TaskBeacon/T000004-flanker
Short Description	Arrow-based Flanker task for selective attention and interference control (behavior/EEG).
Created By	Zhipeng Cao (zhipeng30@foxmail.com)
Date Updated	2026-03-02
PsyFlow Version	0.1.9
PsychoPy Version	2025.1.1
Modality	Behavior/EEG
Language	Chinese
Voice Name	zh-CN-YunyangNeural

1. Task Overview

Participants judge the direction of the center arrow while ignoring flankers. The task includes congruent and incongruent conditions and measures RT/accuracy interference effects.

2. Task Flow

Block-Level Flow

• Load config, runtime mode, triggers, window, and stimuli.
• Show instruction screen.
• Run block/trial loops with condition scheduling from BlockUnit.generate_conditions().
• Show block summary screen and continue prompt.
• Save outputs and close runtime resources.

Trial-Level Flow

• pre_stim_fixation: fixation cross.
• flanker_response: flanker string display with response capture.
• inter_trial_interval: blank ITI before next trial.

Controller Logic

• Condition generation uses config-defined task.conditions with built-in balanced scheduling.
• Correct key is inferred from condition token suffix (left/right).
• No trial-level reward controller; block-level accuracy is computed from stimulus_hit.

Runtime Context Phases

Phase Label	Meaning
pre_stim_fixation	Fixation stage responder context in src/run_trial.py.
flanker_response	Response stage responder context in src/run_trial.py.

Runtime Modes

• Human (default): python main.py
• QA: python main.py qa --config config/config_qa.yaml
• Scripted sim: python main.py sim --config config/config_scripted_sim.yaml
• Sampler sim: python main.py sim --config config/config_sampler_sim.yaml

3. Configuration Summary

• config/config.yaml: base human profile
• config/config_qa.yaml: QA profile
• config/config_scripted_sim.yaml: scripted sim profile
• config/config_sampler_sim.yaml: sampler sim profile

a. Subject Info

Field	Type	Constraints
subject_id	int	3 digits, 101-999
subname	string	free text
age	int	5-60
gender	choice	Male, Female

b. Window Settings

Key	Value
size	[1920, 1080]
units	deg
screen	1
bg_color	gray
fullscreen	true
monitor_width_cm	60
monitor_distance_cm	72

c. Stimuli

Stimulus ID	Type	Role
fixation	text	fixation cross (+)
congruent_left	text	<<<<<
congruent_right	text	>>>>>
incongruent_left	text	>><>>
incongruent_right	text	<<><<
instruction_text	textbox	participant instructions
block_break	text	inter-block summary
good_bye	text	closing message

d. Timing

Timing Key	Human Config
fixation_duration	0.5
stim_duration	1.0
iti_duration	[0.8, 1.2]

e. Triggers

Event	Code
exp_onset	98
exp_end	99
block_onset	100
block_end	101
fixation_onset	1
congruent_stim_onset	10
incongruent_stim_onset	20
left_key_press	30
right_key_press	31
response_timeout	32

4. Methods (for academic publication)

Participants performed an Eriksen Flanker paradigm in which the center arrow direction was reported while flanker arrows were ignored. Each trial included a fixation period, followed by a flanker display with a bounded response window, then a jittered inter-trial interval. Conditions included congruent (<<<<<, >>>>>) and incongruent (>><>>, <<><<) displays with left/right target directions. Interference effects are quantified from reaction time and accuracy differences between congruent and incongruent conditions.

5. References

1. Eriksen, B. A., & Eriksen, C. W. (1974). Effects of noise letters upon the identification of a target letter in a nonsearch task. Perception & Psychophysics, 16(1), 143-149.
2. Ridderinkhof, K. R., van der Molen, M. W., Band, G. P., & Bashore, T. R. (1997). Sources of interference from irrelevant information: A developmental study. Journal of Experimental Child Psychology, 65(3), 315-341.
3. Botvinick, M. M., Braver, T. S., Barch, D. M., Carter, C. S., & Cohen, J. D. (2001). Conflict monitoring and cognitive control. Psychological Review, 108(3), 624-652.
4. Fan, J., McCandliss, B. D., Sommer, T., Raz, A., & Posner, M. I. (2002). Testing the efficiency and independence of attentional networks. Journal of Cognitive Neuroscience, 14(3), 340-347.