Spatial compatibility · Inhibition

Simon Task

The Simon effect was first reported by Simon & Rudell (1967): irrelevant spatial position influences your response. Respond by color while position tries to mislead you.

DifficultyExpert = strict academic parameters

Age band (for scoring reference)Not signed in (scores won't count toward profile)

Intermediate: 48 trials, 2s per stimulus.

A circle appears on the left or right of the screen. Respond by COLOR only — ignore the position. Red = press the ← key (or the "Left" on-screen button). Blue = press the → key (or "Right"). One key per trial.

History

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References: Simon & Rudell (1967); Simon (1969); Lu & Proctor (1995).

Scientific basis

Simon Task · scientific basis

Spatial compatibility & inhibition

Simon effect was first reported by Simon & Rudell (1967): irrelevant spatial location interferes with responding. Lu & Proctor (1995) provide the canonical review; Hommel (2011) offers theoretical framework.

Expert-mode parameters

These are the standard parameters from the canonical paradigm (used by the "Expert" difficulty).

Parameter	Standard value	Source
Stimulus duration (Expert)	Until response (1500ms deadline)	Simon 1969
ITI	500 ms	Common
Trial count	96	Common standard
Compatible:Incompatible	50:50	Standard balance

Healthy-population norms (by age)

Simon effect = RT_incompatible − RT_compatible. Thresholds derived from Van der Lubbe 2002, Davidson 2006 (children/teens) and Pick & Proctor 1999 mean/SD by age band; 'excellent' corresponds to mean − 1 SD. The Simon effect is largest in children, smallest at 18-34 y, and rises markedly in older adults (especially 65+). Assessment mode matches your actual age.

Limitations： Peer-reviewed Simon norms are scattered. Primary sources: Simon & Rudell 1967 (original paradigm), Hommel 2011 (theoretical review), Van der Lubbe 2002 (adults), and Davidson 2006 (developmental, ages 4-13). Bands 14-17, 35-44 and 45-54 y are mostly interpolated from neighbours (flagged est in norms.ts); 65+ leans on Pick & Proctor 1999 and Van der Lubbe 2005 aging studies. Simon effect is sensitive to parameters (visual vs. auditory, stimulus location, response window). This module uses the visual version with 50:50 ratio — consistent with standard literature but still expect 5-15 ms variability. Cross-reference with Flanker or Stroop (also spatial/conflict-inhibition paradigms in this app).

Age band	Simon effect Excellent (ms)	Accuracy mean	Simon effect mean (ms)	Evidence
Age 8-9	≤ 25	~94%	~60	medium
Age 10-11	≤ 17	~96%	~45	medium
Age 12-13	≤ 15	~97%	~40	medium
Age 14-15	≤ 13	~97%	~35	weak (interp.)
Age 16-17	≤ 10	~98%	~30	weak (interp.)
Age 18-24	≤ 8	~98%	~26	strong
Age 25-34	≤ 8	~98%	~26	strong
Age 35-44	≤ 10	~97%	~30	weak (interp.)
Age 45-54	≤ 15	~97%	~40	weak (interp.)
Age 55-64	≤ 23	~96%	~55	medium
Age 65+	≤ 40	~95%	~85	medium

Standard output metrics

·Mean RT per condition — Compatible / incompatible separately
·Simon effect (ΔRT) — Incompatible − compatible
·Accuracy per condition —
·Post-error slowing — Optional

Citations

Simon, J. R., & Rudell, A. P. (1967). Auditory S-R compatibility. J Appl Psychol, 51(3), 300-304. DOI
Simon, J. R. (1969). Reactions toward the source of stimulation. J Exp Psychol, 81(1), 174-176. DOI
Lu, C.-H., & Proctor, R. W. (1995). The influence of irrelevant location information on performance. Psychonomic Bulletin & Review, 2(2), 174-207. DOI
Hommel, B. (2011). The Simon effect as tool and heuristic. Acta Psychol, 136(2), 189-202. DOI

All reference ranges come from published peer-reviewed literature. For personal training reference only — not a medical diagnosis. Full methodology: docs/PARADIGMS.md.

This tool is for educational and entertainment purposes only and does not constitute medical advice or a clinical diagnosis.