Table 1.

Number of dimensions of various spaces involved in sensory discrimination

DOI: http://dx.doi.org/10.7554/eLife.07865.007

	Toy microbe	Ring model	Human color	E. coli smell	Human smell
Stimuli	∞	∞	∞	∞	∞
Receptors	∞	∞	3	5	∼400
Percepts	1	1	3	1	1–20?

The symbol ∞ stands for ‘very large or infinite’.