Flanker task

In cognitive psychology, the Eriksen Flanker Task is a set of response inhibition tests used to assess the ability to suppress responses that are inappropriate in a particular context. The target is flanked by non-target stimuli which correspond either to the same directional response as the target (congruent flankers), to the opposite response (incongruent flankers), or to neither (neutral flankers). The task is named for Barbara. A. Eriksen & Charles W. Eriksen, who first published the task in 1974, and also for the flanker stimuli that surround the target. In the tests, a directional response (usually left or right) is assigned to a central target stimulus. Various forms of the task are used to measure information processing and selective attention.

In an Eriksen Flanker Task there are three types of stimuli used:

In the original test described by Eriksen and Eriksen in 1974, letter stimuli were used. Subjects were instructed to make directional responses to certain letters, for example a right response could be associated to the letters H and K, and a left response to S and C. Each stimulus consisted of a set of seven letters, with the target stimulus placed in the central position. Examples of congruent stimuli would be HHHKHHH and CCCSCCC, where both the target stimulus and the flankers correspond to the same directional response. Examples of incongruent stimuli could be HHHSHHH and CCCHCCC , where the central target letter and the flankers correspond to opposite directional responses. Choice reaction times (CRTs or RTs) were then recorded and compared between congruent and incongruent conditions.

Other variants of the Eriksen Flanker Task have used numbers, color patches, or arrows as stimuli. Also, although most Eriksen Flanker Tasks show the flankers on the left and right of the target, they can also be placed above or below the target, or in other spatial orientations.These examples all use an arbitrary mapping between the stimulus and the response. Another possibility is to use a natural mapping, with arrows as stimuli. For example, Kopp et al. (1994) used left and right arrows, with flanker stimuli above and below the target. The flankers could be arrows pointing in the same direction as the target (congruent) the opposite direction (incongruent) or squares (neutral). More commonly, flankers have been arranged in a horizontal array, as with letter stimuli, so <<<<< would be a congruent stimulus, <<><< an incongruent stimulus.

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