Simon Task

HED Task ID: hedtsk_simon

Also known as: Simon Effect Task, Spatial Compatibility

Non-spatial feature (e.g. color) dictates a left/right response while task-irrelevant stimulus location varies; RT cost on incongruent trials indexes spatial response conflict.

Description

The Simon Task measures the effect of spatial stimulus-response correspondence on performance. Participants respond to a non-spatial stimulus attribute (e.g., color: press left for red, right for blue) while the stimulus appears on either the left or right side of the screen. When stimulus location corresponds with the assigned response side (congruent), responses are faster and more accurate than when they do not correspond (incongruent). The Simon effect reflects automatic activation of a spatially corresponding response that must be overridden when incongruent. The task is a foundational paradigm for studying stimulus-response compatibility and dimensional overlap.

Inclusion test

Procedure

Stimuli varying on a non-spatial attribute (color, shape) appear on the left or right; participants respond with spatially mapped keys. On incongruent trials, stimulus location conflicts with response location.

Manipulation

Spatial congruency (stimulus side matches or conflicts with response side); stimulus eccentricity; proportion congruent.

Measurement

Simon effect (RT difference: incongruent − congruent); accuracy; delta-plot analysis of time-course of interference.

Variations

Variation

Description

Justification

Visual Simon Task (Standard)

Colored stimuli at lateral screen positions; button-press responses.

Canonical: respond to color/shape despite irrelevant spatial position

Auditory Simon Task

Tones presented to left/right ear; key-press responses.

Auditory stimulus location as irrelevant dimension; different sensory modality

Vertical Simon Task

Stimuli above/below fixation with top/bottom responses.

Vertical rather than horizontal spatial dimension; different axis of conflict

Simon Task with Accessory Stimuli

Irrelevant tones accompanying visual stimuli to study cross-modal Simon effects.

Non-response-relevant accessory stimulus added; tests alerting-compatibility interaction

Reversed Simon Task

Instructions to respond opposite to stimulus location; studies intentional override.

Stimulus-response mapping reversed; opposite compatibility mapping

Joint Simon Task

Two participants each handle one response key; social Simon effect emerges.

Two participants share one Simon task; tests social simulation of co-actor’s response

Hybrid Simon-Flanker Task

Combines spatial correspondence with flanker interference.

Integrates flanker conflict with Simon conflict; combined interference paradigm

Emotional Simon Task

Emotional stimuli presented at lateral locations.

Emotional content as irrelevant dimension; retained per §5.1 (EMOT retired)

Mouse-Tracking Simon

Continuous mouse trajectories reveal temporal dynamics of conflict resolution.

Continuous mouse trajectory as response; different response modality

Simon with Proportion-Congruent Manipulation

Varying congruent/incongruent ratios to study context-driven control.

Varies conflict frequency; adaptation context manipulation per §5.2

Cognitive processes

This task engages the following cognitive processes:

Key references

  • {‘authors’: ‘Simon, J. R., & Rudell, A. P.’, ‘year’: 1967, ‘title’: ‘Auditory S-R compatibility: The effect of an irrelevant cue on information processing.’, ‘venue’: ‘Journal of Applied Psychology’, ‘venue_type’: ‘journal’, ‘journal’: ‘Journal of Applied Psychology’, ‘volume’: ‘51’, ‘issue’: ‘3’, ‘pages’: ‘300-304’, ‘doi’: ‘10.1037/h0020586’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Simon, J. R., & Rudell, A. P. (1967). Auditory S-R compatibility: The effect of an irrelevant cue on information processing. Journal of Applied Psychology, 51(3), 300–304.’, ‘url’: ‘https://doi.org/10.1037/h0020586’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}

  • {‘authors’: ‘Kornblum, S., Hasbroucq, T., & Osman, A.’, ‘year’: 1990, ‘title’: ‘Dimensional overlap: Cognitive basis for stimulus-response compatibility–A model and taxonomy.’, ‘venue’: ‘Psychological Review’, ‘venue_type’: ‘journal’, ‘journal’: ‘Psychological Review’, ‘volume’: ‘97’, ‘issue’: ‘2’, ‘pages’: ‘253-270’, ‘doi’: ‘10.1037/0033-295x.97.2.253’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Kornblum, S., Hasbroucq, T., & Osman, A. (1990). Dimensional overlap: Cognitive basis for stimulus-response compatibility—A model and taxonomy. Psychological Review, 97(2), 253–270.’, ‘url’: ‘https://doi.org/10.1037/0033-295x.97.2.253’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}

  • {‘authors’: ‘De Jong, R., Liang, C., & Lauber, E.’, ‘year’: 1994, ‘title’: ‘Conditional and unconditional automaticity: A dual-process model of effects of spatial stimulus-response correspondence.’, ‘venue’: ‘Journal of Experimental Psychology: Human Perception and Performance’, ‘venue_type’: ‘journal’, ‘journal’: ‘Journal of Experimental Psychology: Human Perception and Performance’, ‘volume’: ‘20’, ‘issue’: ‘4’, ‘pages’: ‘731-750’, ‘doi’: ‘10.1037/0096-1523.20.4.731’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘De Jong, R., Liang, C.-C., & Lauber, E. (1994). Conditional and unconditional automaticity: A dual-process model of effects of spatial stimulus-response correspondence. Journal of Experimental Psychology: Human Perception and Performance, 20(4), 731–750.’, ‘url’: ‘https://doi.org/10.1037/0096-1523.20.4.731’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}

Recent references

  • {‘authors’: ‘Hommel, B.’, ‘year’: 2011, ‘title’: ‘The Simon effect as tool and heuristic’, ‘venue’: ‘Acta Psychologica’, ‘venue_type’: ‘journal’, ‘journal’: ‘Acta Psychologica’, ‘volume’: ‘136’, ‘issue’: ‘2’, ‘pages’: ‘189-202’, ‘doi’: ‘10.1016/j.actpsy.2010.04.011’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Hommel, B. (2011). The Simon effect as tool and heuristic. Acta Psychologica, 136(2), 189–202.’, ‘url’: ‘https://doi.org/10.1016/j.actpsy.2010.04.011’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}

  • {‘authors’: ‘Wiegand, K., & Wascher, E.’, ‘year’: 2005, ‘title’: ‘Dynamic Aspects of Stimulus-Response Correspondence: Evidence for Two Mechanisms Involved in the Simon Effect.’, ‘venue’: ‘Journal of Experimental Psychology: Human Perception and Performance’, ‘venue_type’: ‘journal’, ‘journal’: ‘Journal of Experimental Psychology: Human Perception and Performance’, ‘volume’: ‘31’, ‘issue’: ‘3’, ‘pages’: ‘453-464’, ‘doi’: ‘10.1037/0096-1523.31.3.453’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Wiegand, K., & Wascher, E. (2005). Dynamic aspects of stimulus-response correspondence: Evidence for two mechanisms involved in the Simon effect. Journal of Experimental Psychology: Human Perception and Performance, 31(3), 453–464.’, ‘url’: ‘https://doi.org/10.1037/0096-1523.31.3.453’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}

  • {‘authors’: ‘Proctor, R. W., Miles, J. D., & Baroni, G.’, ‘year’: 2011, ‘title’: ‘Reaction time distribution analysis of spatial correspondence effects’, ‘venue’: ‘Psychonomic Bulletin & Review’, ‘venue_type’: ‘journal’, ‘journal’: ‘Psychonomic Bulletin & Review’, ‘volume’: ‘18’, ‘issue’: ‘2’, ‘pages’: ‘242-266’, ‘doi’: ‘10.3758/s13423-011-0053-5’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Proctor, R. W., Miles, J. D., & Baroni, G. (2011). Reaction time distribution analysis of spatial correspondence effects. Psychonomic Bulletin & Review, 18(2), 242–266.’, ‘url’: ‘https://doi.org/10.3758/s13423-011-0053-5’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}

  • {‘authors’: ‘Salzer, Y., de Hollander, G., & Forstmann, B. U.’, ‘year’: 2017, ‘title’: ‘Sensory neural pathways revisited to unravel the temporal dynamics of the Simon effect: A model-based cognitive neuroscience approach’, ‘venue’: ‘Neuroscience & Biobehavioral Reviews’, ‘venue_type’: ‘journal’, ‘journal’: ‘Neuroscience & Biobehavioral Reviews’, ‘volume’: ‘77’, ‘issue’: None, ‘pages’: ‘48-57’, ‘doi’: ‘10.1016/j.neubiorev.2017.02.023’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Salzer, Y., de Hollander, G., & Forstmann, B. U. (2017). Sensory neural pathways revisited to unravel the temporal dynamics of the Simon effect: A model-based cognitive neuroscience approach. Neuroscience & Biobehavioral Reviews, 77, 48–57.’, ‘url’: ‘https://doi.org/10.1016/j.neubiorev.2017.02.023’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}