pavlovian response to food

In anticipation of eating it.

1) "The production of saliva is stimulated both by the sympathetic nervous system and the parasympathetic. The saliva stimulated by sympathetic innervation is thicker, and saliva stimulated parasympathetically is more watery." Source and further information: http://en.wikipedia.org/wiki/Saliva Further information: http://www.lib.mcg.edu/edu/eshuphysio/program/section6/6ch4/s6ch4_7.htm http://en.wikipedia.org/wiki/Salivary_gland 2) "Secretion of saliva is under control of the autonomic nervous system, which controls both the volume and type of saliva secreted. This is actually fairly interesting: a dog fed dry dog food produces saliva that is predominantly serous, while dogs on a meat diet secrete saliva with much more mucus. Parasympathetic stimulation from the brain, as was well demonstated by Ivan Pavlov, results in greatly enhanced secretion, as well as increased blood flow to the salivary glands. Potent stimuli for increased salivation include the presence of food or irritating substances in the mouth, and thoughts of or the smell of food. Knowing that salivation is controlled by the brain will also help explain why many psychic stimuli also induce excessive salivation - for example, why some dogs salivate all over the house when it's thundering" Source and further information: http://www.vivo.colostate.edu/hbooks/pathphys/digestion/pregastric/salivary.html

It's your body's natural way of preparing itself for the digestive process which begins with saliva. Similar to when a guy gets a boner when he sees a hot chick.