Environmental cleanliness: what is cognitively fresh? The concept of freshness has developed over the last century to involve a range of sensations and responses to tastes, smells and feelings associated with foods, the environment and cleaning products. But what is it that contributes or tells us that something is fresh from a neurocognitive perspective? It seems unlikely that freshness be merely the absence of negative stimuli that promote a disgust response, as freshness is often associated as a positive response. 

I know this is a wide ranging question, however there is surprisingly little research on a concept that advertisers use daily, to promote cleaning products. Its unusual that such a important perception and its associated behaviour has so little academic research. Funny how merely watching the adverts between TV shows can make you curious!

EDIT:

The exact questions are...


What are the cognitive factors that make humans or animals perceive something to be fresh/clean?
What are the neurocognitve mechanisms underlying these processes?
Freshness is a term which is widely used to identify odors. The olfactive stimuli which is trigerred by fragrant materials like citruses, aromatics( lavender, rosemary), peppermints or green materials (like leafs or grass) these are more volatile groups they are light molecules and usually refer to freshness. But the cool or fresh sensation not just come from the olfactive perception or identification it is because of the trigeminal nerve fibers which are responsible of sensing temperature and irritating substances. It is both temperature and the identification why there is a common freshness perception.

EDIT: All the cleansing products which are perfumed, tested durig the wet and dry stages to examine power and hedonic scales. So perfumes inside the product need to be percieved during wet and dry stages and fragrant materials need to diffuse quickly to create a first impression: here something is about to be all clean. These kind of diffusion only obtained with the volatilest chemicals which are mostly triggered trigeminal nerves and creating a fresh or cool sensation.

Doty RL. Intranasal trigeminal detection of chemical vapors by humans.

Interactions between Olfaction and the Trigeminal System: What Can Be Learned from Olfactory Loss