The data on pajama-donning and -doffing is scant. What is available suggests that nightwear is, indeed, somewhat of a sartorial Potemkin: Worn to give the appearance of propriety before bed, then cast off as soon as most of its wearers hit the sheets.
In 2004, ABC News conducted a telephone poll of 1,501 American adults and found that, contrary to my theory, a nightgown or pajamas were the most common sleepwear option. But just a slight majority of women chose this option, and only 13 percent of men did. Most men said they slept either naked or in their underwear.