Table 2. Humor Coding Scheme Applied to 10-s Intervals of Sibling Interaction Containing Laughter.

Humor categories	Examples
Note. Categories could co-occur. FC = focal child.
a. Performing incongruities: Enacting a conflict between what is normal/expected and reality with an object. For example, placing an object in a wrong location or making a toy perform a wrong action.	FC puts teacup on head. FC throws their own hat against the wall.
b. Word play: Nonsense words, rhyming words, riddles, jokes, label-based humor. Making deliberate mistakes in language or changing words in well-known songs.	FC says, “Wait a minute, this is hotsie totsie.” FC “A pirate goes nee-nor-nee-nor!”
c. Preposterous statements and humorous anecdotes: Creating absurd or unusual stories, anecdotes, or making announcements, nonsense sentences, deliberate falsehoods (identified by conflicting statements).	FC “I’m arrested for eating cake!” FC “[Robbers] steal money and jewels and… bears!”
d. Sound play: Over exaggerated vocalizations or speech, exaggerated gasps, animal noises, using a very deep or gruff voice in a silly or unconventional way (e.g., fast or slow), or using silly accents, chanting, bursting into exaggerated song.	FC (Singing) “Oh a-ding-ding!” FC (Squeaky voice while waving) “Hello hello!”
e. Taboo: Disgusting noises, such as blowing raspberries, fart noises, burp noises, using taboo words or discussion and/or enacting taboo themes. Includes violent themes of play, like stabbing, shooting, or terms like “die!” Any play that is rule breaking (yet playful) in nature.	FC pretends to pour into a teacup, then “throws” the tea in younger sibling’s face. FC uses play knife to “saw” sibling’s arm off.
f. Playful teasing: Light-hearted, playful, mischievous behavior directed to play partner. Includes light-hearted insults and playful rough and tumble. Must be coupled with playful cues (smiling, laughter, playful tone of voice).	FC “[Sibling name] gets the saucer and I get the teapot so [Sibling name] can’t have any tea!” FC, smiling, steals hat from sibling.
g. Clowning: Silly or over exaggerated body movements, dancing, posing or pulling funny faces.	FC pokes tongue out at sibling. FC jumps around the room like a frog.