What is the Flanker Effect?

The Flanker Effect is the phenomenon where reaction times are slower and errors increase when the central target and surrounding flankers point in different directions (incongruent condition). This demonstrates how irrelevant information interferes with cognitive processing.

What cognitive abilities does it measure?

The Flanker Task primarily measures selective attention (focusing on relevant information), interference control (suppressing irrelevant information), processing speed, and conflict monitoring. These are key components of executive function.

How is it different from the Stroop Test?

The Stroop Test measures conflict between linguistic (word meaning) and perceptual (color) information, while the Flanker Task measures spatial interference. The Flanker Task is language-independent, making it more universally applicable.

How can I improve my score?

Focus only on the central arrow and use peripheral vision for the flankers. Stay relaxed and respond quickly. The 4-direction mode is harder, so practice with 2-direction mode first.

Flanker Task Explained: The Science of Selective Attention [2026 Guide]

Q: What is the Flanker Task?

The Flanker Task is a cognitive test where you identify the direction of a central target stimulus while ignoring surrounding distractors (flankers). It was first published in 1974 by Barbara A. Eriksen and Charles W. Eriksen. It measures selective attention and interference control.

What is the Flanker Task?

The Flanker Task is a classic psychology experiment that measures selective attention and cognitive control. A target (such as an arrow) is displayed in the center of the screen, flanked by distractor stimuli called "flankers" on both sides. Participants must ignore the surrounding flankers and quickly identify the direction of the central target.

For example, if "←←→←←" is displayed, the correct answer is "right (→)." Because the flankers point left, you might be tempted to answer left, but you need to focus only on the central arrow.

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Scientific Background

Discovery by the Eriksens

In 1974, American psychologists Barbara A. Eriksen and Charles W. Eriksen published "Effects of Noise Letters upon the Identification of a Target Letter in a Nonsearch Task" in Perception & Psychophysics.

In the original experiment, letter stimuli were used. Participants were instructed to make directional responses to certain letters (e.g., respond right to H and K, left to S and C). Each trial displayed seven letters, with the target in the central position.

Congruent condition example: HHHKHHH (center and flankers indicate the same response)
Incongruent condition example: HHHSHHH (center and flankers indicate different responses)

The Flanker Effect Mechanism

The Flanker Effect is the phenomenon where reaction times increase and errors become more frequent in incongruent conditions. This is explained by "response competition." The flankers suggest a different response, creating competition with the correct response to the target.

The Two-Phase Model of Attention

The Eriksens proposed the "Two-Phase Model of Spatial Selective Attention." In the first phase, attention is broadly distributed, and flanker information is also processed. In the second phase, attention narrows to the target, and interference is suppressed. This model remains widely supported today.

Brain Mechanisms

Neuroscience research has identified the following brain regions involved in the Flanker Task:

Anterior Cingulate Cortex (ACC): Conflict detection and monitoring
Dorsolateral Prefrontal Cortex (DLPFC): Cognitive control and attention modulation
Parietal Cortex: Spatial attention allocation
Primary Motor Cortex: Response selection and execution

The anterior cingulate cortex plays a particularly important role in adjusting cognitive control between trials. Greater conflict on one trial leads to enhanced control on the next trial.

Cognitive Abilities Measured

Selective Attention

The ability to focus on relevant information (target) while ignoring irrelevant information (flankers).

Interference Control

The ability to suppress interference from distractors and maintain accurate responses. Related to impulse control.

Conflict Monitoring

The ability to detect conflicting information and resolve cognitive conflicts.

Processing Speed

The ability to quickly process visual information and convert it into accurate motor responses.

How to Play

Start the Game
Click the "Start" button to begin. Aim to answer as many correctly as possible within the time limit.
Identify the Center Arrow
Five arrows appear on the screen. Quickly identify the direction of the center arrow (highlighted in yellow).
Press the Direction Button
Click the button for the direction the center arrow points, or use the keyboard arrow keys.
Score Points
Correct answers add to your score. Consecutive correct answers earn streak bonuses.

Game Modes

2-Direction Mode (Default)

Uses only left and right directions. Suitable for beginners and basic training.

4-Direction Mode

Uses all four directions (up, down, left, right). Requires more complex cognitive control.

No Highlight Mode

Turns off the center arrow highlighting. You must identify the center on your own, increasing difficulty.

Score Guide

Score	Level	Description
Under 20	Beginner	Strongly affected by the Flanker Effect
20-29	Intermediate	Developing selective attention
30-39	Advanced	Shows high interference control ability
40+	Expert	Excellent selective attention and processing speed

Understanding Your Flanker Effect

The "Flanker Effect" shown at the end of the game represents the difference in reaction time between congruent and incongruent trials.

Under 10ms: Very efficient interference control
10-30ms: Average Flanker Effect
Over 30ms: Strongly affected by flanker interference

A smaller difference means you're responding without being distracted by the flankers.

Tips and Strategies

Fix Your Gaze on the Center - Keep your eyes fixed on the screen center to avoid looking at surrounding arrows. Using peripheral vision for flankers increases interference.
Maintain a Rhythm - Responding at a consistent rhythm stabilizes reaction speed. Rushing leads to more errors on incongruent trials.
Start with 2-Direction Mode - Practice in 2-direction mode first, then try 4-direction mode once your accuracy is stable.
Use the Keyboard - Arrow keys allow faster responses than button clicks.
Take Short Sessions - Short sessions (15-30 seconds) repeated before focus fades are more effective.

Research Applications

The Flanker Task is used in various fields:

Developmental Psychology

Research on children's cognitive control development
ADHD diagnosis and assessment
Studies on age-related cognitive changes

Neuroscience

Brain activity research using fMRI and EEG
Understanding neural mechanisms of conflict monitoring
Studies on cognitive control networks

Clinical Psychology

Assessment of attention disorders
Measuring cognitive rehabilitation effectiveness
Research on cognitive function in mental disorders

Combining with Dual N-Back

The Flanker Task and Dual N-Back target different cognitive functions.

Feature	Flanker Task	Dual N-Back
Primary Target	Selective attention & interference control	Working memory
Cognitive Load	Spatial interference suppression	Information retention and updating
Time Frame	Momentary decisions	Sequential memory (N steps back)
Session Length	15-60 seconds	15-20 minutes

Combining both allows you to comprehensively train different aspects of executive function.

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FAQ

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Conclusion

Since the Eriksens' 1974 research, the Flanker Task has been widely used as a standard experimental paradigm for measuring selective attention and cognitive control. Though the task is simple—responding to a central target while ignoring surrounding distractors—it reveals how our attention control systems work.

As a language-independent visual task, it's accessible regardless of age or language. Experience the Flanker Effect and test your selective attention abilities!

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