The Eriksen Flanker Paradigm measures the effect of conflicting information within a stimulus set. The subject must focus on a target stimulus while ignoring adjacent flanker stimuli. Besides the Stroop and Simon paradigm, the Eriksen Flanker paradigm is one of the three popular tasks to study effects of conflicting stimulus information.

To measure how conflicting information affects choice response speed, different conditions are introduced:

• Congruent
  All stimuli map to the same response.
• Incongruent
  The flanker stimuli map to a different response than the target stimulus.
• Neutral
  The flanker stimuli have no associated response.

In addition, costs of shifting instructions may be studied by asking the subject to switch focus between central and flanker stimuli depending on a cue.

Conflict scores are computed by subtracting the faster condition from the slower condition for each of the attention concepts:

• Inhibition: InCongruent – Congruent (response conflict)
  Shifting: Mixed Focus – Single Focus (task switching)

The executive subsystem in the Attentional Network Test corresponds to the Eriksen inhibition score.

This implementation uses arrows or fishes as stimulus material. The ladder is known as the children’s version of the flanker task.