(Functional shift) happens when one part of speech is suddenly transformed into another with a different function but hardly any change of form. It sounds dull but in performance is almost electrically exciting in its sudden simple reach for a word. For example: an adjective is made a verb when in The Winter's Tale heavy thoughts are said to 'thick my blood'. A pronoun is made into a noun when Olivia in Twelfth Night is called 'the cruellest she alive'. Prospero turns adverb to noun when he speaks so wonderfully of 'the dark backward' of past time; Edgar turns noun to verb when he makes the link with Lear: 'He childed as I fathered.' As Abbott says, in Elizabethan English 'You can "happy" your friend, "malice" or "foot" your enemy, or "fall" axe on his head.' Richard II is not merely deposed (that's Latinate paraphrase): he is unkinged."The Shakespeared Brain" (Thanks, Mumbles Mumbach!)
This mental instrument of fresh linguistic coinage, which Shakespeare used above all, holds in small within itself three great principles. Namely: the creative freedom and fluidity of the language at the time; the economy of energy it offered for suddenly compressed formulations; and the closeness of functional shift to metaphor - that characteristic mental conversion that Shakespeare so loved - in the dynamic shifting of senses.
Functional shift was small and tight enough for experimentation. Up until now the main cognitive research done on the confusion of verbs and nouns has been to do with mistakes made by those who are brain-damaged. But hardly anybody appears to have investigated the neural processing of a 'positive error', such as functional shift in normal healthy people. We decided to try to see what happens when the brain comes upon these sudden new formulations in Shakespeare.