In 2012, Lucia Jacobs, an animal behaviorist at Berkeley, proposed that the size of the olfactory bulb, the neural structure that helps all animals smell, was less about "odorant discrimination and acuity" and more about navigation. Her paper, published in the Proceedings of the National Academy of Sciences, suggested that this reasoning explained why there was a pattern in the scale of olfactory bulb sizes in animals, even those that relied more on their eyes than their noses to survive.

— Read more at Your sense of direction is intrinsically linked to your sense of smell at MNN.

Whenever we inhale, the receptors most closely matched to a particular scent will signal first.

But if you take a deeper sniff in that wineglass, you will inhale many more scent molecules, which can activate less specific receptors. Those added signals should dramatically change the scent, but they don’t, a riddle sensory neuroscientists call “concentration-invariance.”

— Read more at Fine-tuned Sense of Smell Relies on Timing: First impressions matter for precise scent identification at Duke Today.