Attention — Selective Attention
Flanker Test
Five arrows appear in a row. Respond to the center arrow only — ignore the flanking arrows. Congruent trials are easy; incongruent trials test selective attention under conflict. 30 trials.
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The Eriksen Flanker Task: Selective Attention Under Conflict
The Eriksen Flanker Task was developed by Barbara and Charles Eriksen in 1974 to study how irrelevant stimuli in the visual periphery interfere with identifying a target stimulus. The key finding — now called the flanker interference effect — is that responses are 80–120ms slower when flanking stimuli point in the opposite direction to the target (incongruent) versus the same direction (congruent).
This test directly measures selective attention: the ability to focus processing resources on relevant information and suppress the influence of irrelevant information. Like the Stroop test, it relies on conflict monitoring in the anterior cingulate cortex, but the Flanker task loads more heavily on spatial selective attention mechanisms in the posterior parietal cortex.
The flanker effect is robust across cultures, ages, and stimulus types. Researchers have used it with letters (H H H S H H H), arrows, fish, and even faces. Arrow versions like this one produce the most pronounced interference effects because arrow direction carries strong spatial-response mapping — your motor system starts preparing a response to the flankers before you've consciously identified the center target.
Congruent vs. Incongruent Performance
The power of the Flanker test lies in the contrast between your two RT scores. A well-functioning selective attention system minimizes the flanker interference effect. Elite performers show effects under 60ms; impaired populations show effects exceeding 200ms. Compare your results to population benchmarks below.
| Trial Type | Example | Avg RT | Error Rate |
|---|---|---|---|
| Congruent | >>>>> | ~420ms | ~4% |
| Incongruent | <<><< | ~520ms | ~21% |
| Flanker effect | Incongruent − Congruent | ~100ms | ~17pp |
Interpreting your flanker effect: Subtract your congruent RT from your incongruent RT. Under 70ms is excellent selective attention. 70–130ms is average. Over 160ms suggests significant executive control difficulty. Unlike simple reaction time, this difference score is largely independent of baseline processing speed.
Score Distribution
Overall accuracy distribution across 1.4 million Flanker test completions. The bimodal shape reflects two populations: those who successfully ignore flankers (~85%+) and those significantly impaired by them (under 70%).
Percentile Reference
| Accuracy | Flanker Effect (RT diff) | Percentile | Classification |
|---|---|---|---|
| 96–100% | <60ms | Top 8% | Exceptional |
| 88–95% | 60–90ms | Top 24% | Excellent |
| 78–87% | 90–130ms | 24th–62nd | Average |
| 65–77% | 130–180ms | 62nd–82nd | Below average |
| <65% | >180ms | Bottom 18% | Well below average |
ADHD, Executive Function, and Flanker Performance
The Eriksen Flanker Task is among the most widely used research tools for studying executive function deficits in ADHD. The flanker interference effect is reliably larger in ADHD populations, but the mechanism differs from what you might expect.
Flanker RT Profiles (ms)
The larger flanker effect in ADHD is partly explained by the alerting hypothesis: ADHD involves dysregulation of the locus coeruleus-norepinephrine system, which provides phasic arousal signals that help the cortex focus resources. Without this signal, irrelevant stimuli compete more successfully with the target.
Research note: Flanker performance is also impaired by sleep deprivation, anxiety, chronic stress, and fatigue — not just ADHD. A single poor night's sleep increases the flanker interference effect by 30–50ms in neurotypical adults. The test is sensitive to executive state, not just stable executive capacity.
How to Improve Your Flanker Performance
Focused attention training
Breath-focused meditation directly trains the attentional control circuits used in the Flanker task. A 2018 meta-analysis found that 8 weeks of focused-attention meditation reduced flanker interference effects by an average of 22ms, with effects transferring to other selective attention tasks. Even 10 minutes per day shows benefit within 3–4 weeks.
Reduce stimulus-response mapping load
Practice with compatible keyboard mappings: left arrow key for left target, right for right. The flanker effect is larger when the response mapping is arbitrary (e.g., pressing "Z" for left). Spatial-response compatibility reduces cognitive load, freeing up inhibitory resources to suppress flanker interference. The Processing Speed test measures this mapping efficiency directly.
Aerobic exercise — acute and chronic
A 2019 study published in Neuropsychologia found that a 20-minute moderate-intensity cycling session reduced flanker interference effects by 18ms in the subsequent hour. The mechanism involves exercise-induced increases in prefrontal dopamine and norepinephrine. Regular exercisers show persistently smaller flanker effects — 15–20ms smaller than sedentary matched controls.
Action video game training
Action video games (AVGs) — fast-paced games requiring rapid target identification amid distractors — are among the most effective interventions for reducing flanker interference. Green & Bavelier's research showed 50 hours of AVG training reduced the flanker effect by 25ms, with effects persisting for 6+ months. The games train the same spatial selective attention circuits without the difficulty ceiling of laboratory tasks.
Track Your Selective Attention
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