Elizabeth Bishop structured “Exchanging Hats” in iambic tetrameter. Iambic refers to an iamb, a common metrical unit in English-language poetry. The iamb consists of two syllables, an unstressed syllable followed by a stressed one. A stressed syllable is where the word gets emphasized in speech. An iambic tetrameter has four iambs in a single line. For example, the first three lines go:

Unfun|ny un|cles who | insist

in try|ing on | a la|dy’s hat,

—oh, ev|en if | the joke | falls flat (Lines 1-3),

Bishop amplifies the strong beat of the iambic tetrameter by using an enclosed rhyme scheme (ABBA) for each stanza. As seen in the excerpt below, each stanza possesses a unique enclosed rhyme scheme:

in spite of our embarrassment. [A]

Costume and custom are complex. [B]

The headgear of the other sex [B]

inspires us to experiment. [A]

Anandrous aunts, who, at the beach [C]

with paper plates upon your laps, [D]

keep putting on the yachtsmen's caps [D]

with exhibitionistic screech [C] (Lines 5-12).

Scholar Rachel Trousdale said rhymed iambic tetrameters are frequently used in light and humorous verse (Trousdale, Rachel. “'I Take off My Hat': Elizabeth Bishop's Comedy of Self-Revelation.” Reading Elizabeth Bishop, edited by Jonathan Ellis, Edinburgh University Press, Edinburgh, 2019.