HUMAN · NERVOUS SYSTEM

REACTION TIME

Test yourself, then watch your own reaction travel through a body — and find the one reflex that never asks the brain.

where this comes from

Measured: your times, in this browser, from the first frame after the green was drawn to your tap's own timestamp. Nothing is sent anywhere. Estimated: how your total splits along the path. The body and brain are the BodyParts3D scan, scaled to a 1.75 m adult; the nerve routes are drawn to follow the real pathways. Education only, not medical advice.

Visual vs auditory reaction time (visual ≈ 250 ms, auditory faster). Jain A, Bansal R, Kumar A, Singh KD. Int J Appl Basic Med Res 2015;5(2):124–127.
Browser reaction-test median ≈ 273 ms. Human Benchmark, reaction time statistics (humanbenchmark.com).
V1 responds ≈ 56 ms after a visual stimulus. Foxe JJ, Simpson GV. Exp Brain Res 2002;142:139–150.
Conscious seeing: EEG signatures ≈ 150–250 ms. Förster J, Koivisto M, Revonsuo A. ERP and MEG correlates of visual consciousness: the second decade. Conscious Cogn 2020;80:102917.
Central motor conduction to the hand ≈ 5–8 ms; hand MEP ≈ 20 ms. Rossini PM et al. Clin Neurophysiol 2015;126:1071–1107 (IFCN TMS guidelines).
Median nerve motor conduction ≥ 49 m/s in healthy adults. Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders, 3rd ed., 2013.
Electromechanical delay ≈ 10–50 ms. Cavanagh PR, Komi PV. Eur J Appl Physiol 1979;42:159–163.
Patellar reflex latency ≈ 20 ms, longer in taller people. Frijns CJM, Laman DM, van Duijn MAJ, van Duijn H. Clin Neurol Neurosurg 1997;99:31–36.
False start: reaction under 0.100 s. World Athletics Technical Rules, TR 16.6.

Path lengths used: eye to finger 1.56 m of nerve; knee to cord 0.69 m, cord back to the quadriceps 0.48 m.