An ecological origin of the asymmetry of human color discrimination: evidence from psychophysics, MEG, and deep neural networks
- 1Department of Psychology, Justus-Liebig-University Giessen, Germany; Department of Experimental Psychology, University of Oxford, Oxford, UK
Abstract
Hue is a powerful cue for object discrimination, but human color discrimination is anisotropic: hue thresholds are lower than chroma thresholds for orangish colors, but nearly equal for purplish colors. Here we show that this asymmetry reflects environmental color statistics rather than being a fixed consequence of cone-opponent architecture. Across fifteen image and reflectance databases, orangish hues accounted for 62.5% of chromatic samples, compared with 5.3% for purplish hues. We replicated the hue-chroma asymmetry psychophysically in 44 participants. Magnetoencephalography revealed a corresponding neural asymmetry, with superior decoding of orangish hue differences emerging around 250 ms after stimulus onset. Deep neural networks trained on naturalistic image datasets reproduced the human-like asymmetry without explicit color supervision. Critically, training on hue-inverted images reversed the asymmetry, producing greater hue sensitivity for purplish than for orangish colors. These results suggest that the geometry of color discrimination is shaped by ecological chromatic structure.
Related
- An exploratory fNIRS study on directional asymmetry in segmental discrimination: Lateral–rhotic (/la–ra/) and labial–dorsal (/ba–ga/) contrasts tested in 5- and 9-month-old Japanese infants
- Metabolic Cost Asymmetry as a Structural Regulariser for Recurrent Spiking Neural Networks
- Multilayer interaction networks reveal multidimensional ecological strategies and context-dependent competition in soil actinobacteria
- Associations between social network characteristics and daily social experiences in later life: evidence from ecological momentary assessment
- Correlated traits generate the structure and stability of multiplex ecological networks
BibTeX
@misc{hedjar2026ecological,
title = {{An ecological origin of the asymmetry of human color discrimination: evidence from psychophysics, MEG, and deep neural networks}},
author = {L. Hedjar and T. Morimoto and A. Akbarinia and M. V. Bartsch and H. Strumpf and J.-M. Hopf and K. R. Gegenfurtner},
howpublished = {bioRxiv},
year = {2026},
month = jun,
doi = {10.64898/2026.06.16.732654},
url = {https://www.biorxiv.org/content/10.64898/2026.06.16.732654v2},
note = {CC BY},
}
RIS
TY - UNPB
TI - An ecological origin of the asymmetry of human color discrimination: evidence from psychophysics, MEG, and deep neural networks
AU - L. Hedjar
AU - T. Morimoto
AU - A. Akbarinia
AU - M. V. Bartsch
AU - H. Strumpf
AU - J.-M. Hopf
AU - K. R. Gegenfurtner
PY - 2026
DA - 2026/06/16
PB - bioRxiv
DO - 10.64898/2026.06.16.732654
UR - https://www.biorxiv.org/content/10.64898/2026.06.16.732654v2
AB - Hue is a powerful cue for object discrimination, but human color discrimination is anisotropic: hue thresholds are lower than chroma thresholds for orangish colors, but nearly equal for purplish colors. Here we show that this asymmetry reflects environmental color statistics rather than being a fixed consequence of cone-opponent architecture. Across fifteen image and reflectance databases, orangish hues accounted for 62.5% of chromatic samples, compared with 5.3% for purplish hues. We replicated the hue-chroma asymmetry psychophysically in 44 participants. Magnetoencephalography revealed a corresponding neural asymmetry, with superior decoding of orangish hue differences emerging around 250 ms after stimulus onset. Deep neural networks trained on naturalistic image datasets reproduced the human-like asymmetry without explicit color supervision. Critically, training on hue-inverted images reversed the asymmetry, producing greater hue sensitivity for purplish than for orangish colors. These results suggest that the geometry of color discrimination is shaped by ecological chromatic structure.
ER -