Cardinality of human olfactory perceptual space

Determine the cardinality of human olfactory perceptual space and reconcile the widely varying estimates of the number of discriminable human odors.

Background

The paper identifies the dimensionality and structure of human olfactory perception as a foundational unresolved issue for computational olfaction. Unlike vision or audition, olfaction lacks a widely accepted low-dimensional set of perceptual primitives, making it difficult to define the target space for odor prediction and generation.

The authors specifically note that estimates of the number of discriminable odors differ by many orders of magnitude. Resolving this uncertainty would provide a more principled basis for representing odor perception and for developing systems that map molecular compositions to perceptual experiences.