Although taste aversion learning is regarded as a kind of Pavlovian conditioning, what is learned in this preparation seems to differ from other Pavlovian paradigms. For example, animals learn to shift the hedonic value of a target taste stimulus followed by toxin in the aversive direction. However, after the pairing taste-CS and shock-US, a taste can acquire a signaling function for the upcoming electric shock, without hedonic shifts. We propose that taste stimuli employed as conditioned stimuli have two properties, i. e., sensory and emotional properties. Accordingly, animals learn relationships between a target taste and another stimulus by two different types of learning, the if-then strategy or the hedonic shift. This assumption is supported by physiological findings and the effects of specific hunger on taste aversion.