Communication with Babies: The Evolution of Language and the Power of Social Bonds
Why do we change our voices when talking to babies, and what’s with those nonsensical syllables? Do you think babies understand what we’re saying? Real-time communication is complex and requires processing multi-dimensional stimuli moment by moment. Babies, as the newest and youngest learners, need time, experience, and neural development to understand the structure of speech. So how do caregivers (parents or others responsible for the baby’s care) speak to help babies focus their attention on speech?
Have you noticed how our tone of voice and the way we speak change when we talk to babies? Why is it crucial to use this simple language, filled with exaggerated and emphasized phrases like “ma-ma” or “pa-pa,” while communicating with infants?
This special form of communication is commonly referred to as “motherese,” “baby talk,” or more formally, “child-directed speech (CDS).” It is characterized by a higher pitch, wider pitch range, and longer pauses, differing from adult communication. Linguistically, this speech pattern is simpler and features easier expressions, frequently asked questions, and repeated single words. However, this special form of communication is not just an odd collection of simple words or cute expressions; it is also a critical tool for bonding, attracting attention, and promoting early language acquisition. When parents lean over the crib and whisper, “Who’s this cute baby? It’s you! Yes, you are!” they are not only expressing love but also laying the foundation for their child’s linguistic future.
Research proves that using motherese is highly effective in expanding babies’ vocabulary and developing their language skills. Babies learn more words during interactions involving motherese and can attach meanings to these words much faster.
Motherese helps babies distinguish sounds and understand the rhythm of speech. Furthermore, establishing such close communication with babies strengthens bonds and provides them with a safe environment. This enables babies to be more receptive to learning new words and developing their language skills.
The evolution and significant benefits of this special speech style have been explored for various reasons. While some theories suggest that this form of speech may help babies learn to speak (by emphasizing vowel sounds), other theories propose that it may help babies regulate their emotional states, while also facilitating their socialization and behavior control by shaping social interactions. This supports the emotional and social development of babies, allowing them to grow into healthy individuals within society.
Researchers from Harvard Music Lab collaborated with about 40 anthropologists worldwide to gather recordings of people speaking to babies, from small-scale communities with lifestyles different from those in Western societies. Published in Nature in 2022, the study documented changes in tone and rhythm while speaking to babies. Even in communities like the Nyang’atom people of East Africa and the Hadza, who live in groups of 30-40 people and are almost entirely isolated from the internet, radio, or television, the tone of voice was observed to be higher while speaking to babies, and the speech was always more rhythmic. Interestingly, the Hadza language is an isolated language, with no known linguistic relatives.
You can listen to recorded conversations with children and adults in various languages from different regions on the study’s related website.
Around 51,000 people from 187 countries listened to recordings collected during the study and were asked to guess which ones were directed at babies. The results were statistically significant. Despite language barriers, participants were able to make accurate guesses. These findings provide significant insights into the psychological functions and evolution of human communication.
Evidence of this phenomenon is commonly seen in various cultures and many languages, while evidence in non-human species is extremely limited. In one study, adult male zebra finches (Taeniopygia guttata) were found to change their songs when near their young, compared to those they sing when alone or near females. Other studies have shown that adult squirrel monkeys (Saimiri sp.), rhesus macaques (Macaca mulatta), and female greater sac-winged bats (Saccopteryx bilineata) alter their sounds when communicating with young conspecifics. However, it is important to note what that these species are doing is different from what we see in humans. They are not simply using different tones of the same sounds but, in fact, produce entirely different sounds (except fort he zebra finches).
Another study published in the Proceedings of the National Academy of Sciences adds a new species to literature, showing that mother bottlenose dolphins (Tursiops truncatus) change their tone of voice and use a high-pitched “baby talk” when addressing their young. This significant discovery was made by Laela Sayigh from the Woods Hole Oceanographic Institution and her colleagues. For about 40 years, researchers have been conducting studies on dolphins in Sarasota Bay, Florida, where they take recordings of dolphins during brief captures.
The study recorded the signature whistles of 19 wild bottlenose dolphin mothers living in Sarasota Bay. These whistles were captured with special microphones, both when the mothers were near their young and when they were apart. Signature whistles are unique and significant signals that help dolphins recognise each other, with each individual having a distinctive sound.
The unique whistles of dolphin mothers may serve an additional communication function as part of their broad and dynamic social networks. Female dolphins, frequently interacting with their conspecifics, may use subtle changes in signature whistles to target their calves or help the calves detect calls directed from their mothers. This contributes to strengthening and maintaining the bond between mother and calf.
However, the research team emphasises in the article that it may be too early to make definitive interpretations. Laela Sayigh, one of the lead authors of the study, highlights the limitations of their findings despite their significance. One alternative scenario, the team suggests, is that this communication facilitates language acquisition and strengthens the bond between the calf and its caregiver, similar to humans. Moreover, it is possible that these changes in whistles are used to specify the target. Sayigh says, “By making these subtle changes, they might be enabling the calf to think, ‘Okay, this was meant for me.'”
The role “motherese” plays in the development of dolphin calves is not yet fully understood. It remains unclear whether it helps the calves comprehend “speaking” or “learning vocal production” as it does in humans.
In summary, the use of “motherese” not only helps human infants develop language skills but also strengthens our bonds with them. This may also be true for other species. For example, the special whistles of mother dolphins for their calves might facilitate communication in their social worlds and strengthen the mother-calf bond. Although there is no definitive picture yet, future studies may provide answers to many questions and offer different perspectives. However, thinking that dolphins coo to their babies sounds absolutely delightful.
REFERENCES
- 1. https://www.pnas.org/doi/10.1073/pnas.2300262120
- 2. https://pubmed.ncbi.nlm.nih.gov/37364108/
- 3. https://www.pnas.org/post/podcast/motherese-bottlenose-dolphins
- 4. https://www.sciencedirect.com/science/article/pii/S0273229722000375
- 5. https://www.npr.org/2022/07/23/1113206642/baby-talk-parenting-language-research
- 6. https://www.nature.com/articles/s41562-022-01410-x
- 7. https://www.popsci.com/science/baby-talk-language-development/