A party hat is generally a playful conical hat made with a rolled up piece of thin cardboard, usually with designs printed on the outside and a long string of elastic acting like a chinstrap, going from one side of the cone's bottom to another to secure the cone to the person's head. Its name originates with its use: Party hats are worn most often at birthday parties, especially by the guest of honor, with a significant minority being worn for New Year celebrations. In Britain the hat is made of paper and is the shape of a crown, and is most typically worn during a Christmas dinner. The party hat has its origins in the dunce cap worn by misbehaving or poorly performing schoolchildren from the mid-19th century to the early 20th century, with its festive decoration and society's positive attitude toward the wearer indicating a relaxation, abrogation, or even reversal of certain social norms: During the occasion in question, the wearer is permitted or encouraged to engage, rather than discouraged from engaging, in frivolous and foolish behavior for which the required wearing of the dunce cap would in other situations constitute a punishment. Party hats have originated in England
Non-conical hats worn to signify an occasion's informal and festive status include decorated top hats, hats made from balloons, the beer hat or "beer helmet" (invented in 1983 by Buffalo Bills fan Jeremy Gumbo), and Mickey Mouse ears. In more extreme cases, partygoers may wear other objects such as lampshades or beer boxes, although the wearing of such objects often meets with social disapproval.
- Harbin, Robert (1997). Secrets of Origami: The Japanese Art of Paper Folding. Courier Dover Publications. p. 48. ISBN 0-486-29707-1.