The flanker task
Measure how much neighbouring arrows that point the other way slow your response to the arrow you are attending to.
Method
Procedure
- A cross appears, then a row of five items at the centre. Respond to the direction of the middle arrow only.
- The outer items point the same way as the middle arrow (congruent), the opposite way (incongruent), or are plain lines (neutral).
- There are 96 trials in a mixed order: 40 congruent, 40 incongruent and 16 neutral. Each display stays for up to 2 seconds.
Responses
- F
- the middle arrow points left
- J
- the middle arrow points right
- Touch
- the Left and Right buttons
Measures
Median reaction time and accuracy for each kind of flanker. The congruency (or flanker) effect, incongruent minus congruent, estimates how much irrelevant neighbouring information interferes with the response. The page also compares the effect after congruent and after incongruent trials.
Practice
Six practice trials tell you after each one which way the middle arrow pointed.
Terms
- Flankers: The items on either side of the target, which should be ignored.
- Congruent, incongruent and neutral: Flankers that match the target, call for the opposite response, or call for no response.
- Congruency effect: Reaction time on incongruent trials minus reaction time on congruent trials.
- Conflict adaptation: The finding that the congruency effect is often smaller after an incongruent trial than after a congruent one.
- Executive function: The processes that keep behaviour on track towards a goal, such as ignoring distracting information.
Experiment
Responses stay in this browser tab. Nothing is stored or sent, and everything is lost when the page is closed or reloaded.
Results
Interpretation
A positive congruency effect means that the flanking arrows were processed even though you tried to ignore them. If incongruent trials were also less accurate, the interference showed in errors as well as in speed. The neutral condition helps to tell whether congruent flankers helped, incongruent flankers hindered, or both.
Comparison with published studies
A positive effect follows the pattern reported by Eriksen and Eriksen (1974). They used letters, not arrows, so their times are not directly comparable.
Limitations
The sequential comparison (after congruent and after incongruent trials) rests on few trials and includes repetitions of the same display, which can by themselves speed responses.
The result comes from one person in one session, on a device whose timing and display are not calibrated. It describes this run, not a stable characteristic of the participant, and a second run could differ by chance alone. Research studies test many participants under controlled conditions and report the average with its variability. The experiment is educational; it is not a test of ability or health.
One row per trial: kind of flankers, direction of the middle arrow, your response, reaction time and outcome. In the file, 1 means yes and 0 means no. The file is created on this device and can be opened in a spreadsheet.
Background
Original findings
Eriksen and Eriksen (1974) asked people to identify a target letter flanked by other letters. Responses were slower when the flanking letters were associated with the opposite response than when they matched the target, even though the participants knew where the target would be. This version uses arrows, a common variant. The difference between incongruent and congruent trials is the congruency effect. Many studies also find that the effect is smaller after an incongruent trial than after a congruent one, which is often taken as a sign of adjustment of control; part of this sequential effect can reflect repetitions of the same display.
Neural basis
Brain-imaging and EEG studies link the conflict between the response to the central arrow and the response to the flankers to the medial frontal cortex, including the anterior cingulate cortex, as in the Stroop task.
References
- 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. https://doi.org/10.3758/BF03203267
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