Again, if you're perceiving it strongly down the sides of the tongue, if it's causing a little bit of salivation, it's likely to be acidity.

同样，如果头两侧强烈地感觉到它，如果它引起了一点点唾液分泌，那很能是酸味。

In an investigative experiment, Pavlov was able to demonstrate in dogs that salivation could be started by non-food stimuli such as bells, buzzers, and tones.

一项调查性实验中，巴甫洛夫狗明了唾液以由非食物刺激物（如铃声、蜂鸣器和音调）开始分泌。