“I got the wrong color can of Axe,” Ms. Swedelson said. “Holy cow.”

Each bottle signifies something to tweens, who are excruciatingly aware of brand image. George Carey, head of Just Kid Inc., a market research firm, said, “More of the brands that market to kids are doing so by trying to own a human value or characteristic.”

LIKE the Sorting Hat from the Harry Potter books, the bottles and cans telegraph how a boy can sort and identify himself. Old Spice advertisements for its Swagger line featured the rap star LL Cool J as a nerd in school, then being transformed into his fabulousness by you-know-what. Anthony’s Body Essentials are available in Energy, Strength, Spirit and Courage. Abercrombie & Fitch’s popular cologne: Fierce.

Why does Jake Guttenberg, a Manhattan seventh grader, use an Axe spray? “I feel confident when I wear it,” he said.

Lyn Mikel Brown, a psychologist at Colby College and an author of a new book, “Packaging Boyhood,” said the products gave boys the mere illusion of choice. In fact, she said, they often preach an extreme, singular definition of masculinity — at a time developmentally when boys are grappling uneasily with identity.

“These are just one of many products that cultivate anxiety in boys at younger and younger ages about what it means to man up,” Ms. Brown said, “to be the kind of boy they’re told girls will want and other boys will respect. They’re playing with the failure to be that kind of guy, to be heterosexual even.”

Even when advertisements are supposed to be crudely humorous or satiric about masculinity — approaches recommended by market researchers to reach high school boys — younger boys take them more literally, Ms. Brown said.