Cognitive Dissonance Definition. Cognitive dissonance occurs when tension arises between a person's attitudes or beliefs and a decision that contradicts those pre-existing modes of thinking. The psychological phenomenon also occurs when a person chooses between two equally attractive or equally unappealing options. According to the Business Dictionary's website, the most common example of cognitive dissonance in the business world is the occurrence of buyer's remorse..
nursery rhyme. a short, simple poem or song for very young children, as Hickory Dickory Dock.
Ring-around-the-roses is, as mentioned in the OP, a nursery rhyme. It is also a common children's game, at least in the US. The exact words vary, as is true of all playground rhymes, but this is the version with which I'm most familiar.