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In an effort to examine the intonational phenomenon of stylized intonation, knock-knock jokes were collected and phonetically analyzed. Results showed intonation that varied considerably from subject to subject but which was nevertheless constrained in a way that supports a hitherto unexamined supposition among musicologists and linguists: that stylized intonation is defined by the musical interval of a minor third. Results showed a preference for intervals approximating a minor third, as well as an unexpected "boundary" role for the minor third itself, which is interpreted as a consequence of physiology.
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Jeremy Day-O’Connell (2010) studied this question.