The Flanker Effect In Somatosensory And Pain Perception

The flanker task is a popular paradigm to study perception interference. In this task, subjects have to respond to a central target flanked by destructors, usually arrows or letters. When the target arrow and the flanking arrows all point to the same direction (when they are congruent:>>>>>or<<<<<), reaction time is shorter and performance is more accurate than when the target arrow points to a different direction than the flanking arrows (>><>>or<<><<), that is, they are incongruent. However, in the traditional flanker studies, applied materials were graphics, text, or emotional facial expressions, the body sensory stimulation was seldomly used. In addition, whether the flanker effect exists in pain stimulation remains as an open issue.The purpose of this study is to explore the flanker effects in tactile and pain field, consisting of two major researches.Study1investigates the flanker effect in tactile field. Twenty-five healthy adults were recruited for this study. In this study, both target and flanker have high (H) and low (L) levels of intensities. Participants were requested to the intensity of targets in3conditions as follows:1.target-only condition;2. Congruent condition:target and flankers were stimulated synchronously with the same intensity;3. Incongruent condition:target and flankers were stimulated synchronously with the different intensities. The results were as follows:1. In comparison with target-only condition, the intensity of target would be significant lower when target and flankers were stimulated synchronously with the same intensity.2. The target intensity would be significant lower in the congruent condition than that in the incongruent condition.3. The accuracy rate in the congruent condition was significant lower than that in the incongruent condition when the target was low intensity; when the target was high intensity, the result was opposite.4. As for the reaction time, we found no obvious flanker effect. Study2investigates the flanker effect in pain field.34healthy adults were recruited for this study.The experimental design is the same with study l.We find that:1. When the targets were low level of intensities, verbal ratings in target-only condition were significant higher than those in congruent conditions, the results were opposite when targets were high level of intensities.2. Accuracy rates of congruent condition were significant higher than those of incongruent condition when the targets were low level of intensities,3. As for the reaction time, we found that when targets were high level intensities, the reaction time of congruent condition was significant shorter than those of incongruent condition, this results was consistent with that in visual field.In summary, flankers influence target in body sensory field. There exist flanker effects in tactile and pain fields, however, their flanker effects are different, and has some inconsistence with that in visual field.