Twins lag behind single children in producing and using gestures like pointing and waving, according to new research.
Those gestures go hand in hand with first words, the researchers report.
Twins produce fewer gestures and gesture to fewer objects than other children, says principal researcher Şeyda Özçalışkan, an associate professor in the psychology department at Georgia State University. Language use also lags for twins, and language—but not gesture—is also affected by sex, with girls performing better than boys.
“The implications are fascinating,” Özçalışkan says. “It shows that gesture and speech go hand in hand in early development in twins. When one is lagging behind so does the other.”
The research found that a lag in gesture can reliably predict a lag in speech. At the same time, lots of gesturing suggests speech is on the way. Parents can help speed their child’s acquisition of language by naming the objects they gesture to.
The lag in gesture among twins may be due to lower parental input, Özçalışkan says. Parents of single children used a greater amount and diversity of gestures than parents of twins. It’s likely, Özçalışkan says, that parents caring for twins engage in shorter conversations with their children, including gesturing less, because their attention is divided and their labor is doubled.
Özçalışkan and her psychology doctoral students Ebru Pinar and Sumeyra Ozturk, along with her collaborator Nihan Ketrez in Istanbul conducted two studies, published in the Journal of Nonverbal Behavior and the Journal of Child Language. The two studies analyzed video data from Turkish families and included three groups of fraternal twins—males, females, and mixed sex twins, as well as two groups of single boys and girls, along with their parents.
Most kids catch up in language
Özçalışkan says she had grown curious about gesture because it had not yet been studied among twins, while language acquisition has been thoroughly researched.
“We’ve known for a long time that children’s early vocabulary shows sex differences,” says Özçalışkan, “with boys having smaller vocabularies than girls their age.”
Girls age 2-3 also produce longer, more complex sentences than boys. Twins are initially at a disadvantage where language is concerned, using fewer words than their singleton peers and forming complete sentences later than singletons. Boys lag the most, with girl-girl twins developing larger vocabularies and more complex sentences than boy-boy twins of comparable age.
Most of the time, these lags are within the normal range of differences, and nothing to worry about. Almost all children will catch up to each other by around age three and a half.
What about twin gestures?
“There was close to nothing in research on gesturing among twins in any language,” Özçalışkan says.
Infants start pointing around 10 months, a few months before they produce their first words. In other words, they point at a dog a few months before they actually say the word “dog.” Gesture helps them convey what they can’t yet communicate in speech and paves the way for children’s early words.
Though reduced parental input may largely explain the lag in gesture and language among twins, Özçalışkan says twins sometimes develop their own systems of communication, even their own “twin language,” which has been shown to delay language acquisition. “Perhaps it also delays the use of gestures,” she says.
On most occasions, a lag in gesture may mean a lag in the next linguistic milestone.
“However, in the event that you see the lag in gesture go on for a long time, it may be a marker of a potential developmental or language delay,” says Özçalışkan. On the other hand, if a child doesn’t talk much at an early age, but frequently uses gesture, a parent can be reassured that “language is on its way,” she says.
The more a parent engages with a child, using gesture and speech, the better the child’s acquisition of both. The two together form a closely integrated system in a child’s development, and a child’s first gestures often precede their first attempts at speech.
For parents who are intrigued by these connections, Özçalışkan suggests naming objects when children point to them, as in: “Yes, that’s a bottle, do you want your bottle?” Naming helps children learn new words earlier. Parents can also make a point of gesturing to objects themselves when naming.
“Gesture is a very powerful tool,” Özçalışkan says. “Pay attention to your child’s gestures, and then provide verbal descriptions to help their language development.”
Source: Georgia State University