Fig 4. Individual differences in aversion to CO2, arranged from the least to the most tolerant rat.
Bigger and solid shapes indicate the mean and error bars show the standard error for each individual rat within each age. Smaller and transparent shapes represent observation from each rat at each age. Each age is presented with a different shape (circles: 3 months, triangles: 9 months, squares: 16 months) and each color represents an individual rat.