Published: October 9th, 2009
Rhesus macaque monkeys communicate with their mothers by certain facial expressions and lip smacking, and a new study suggests the meaning behind these signals. Recently, evidence has come to pass that illustrates how early facial expressions and lip smacking can prepare a young macaque for the adult social world. Pier Ferrari and his colleagues of the University of Parma in Italy have collected the bulk of the data.
Indicators begin very overstated, almost play-like, with the adult mother leading the way for her young. A mother macaque will gently touch her baby’s face with her lips and nod her head to signal the start of eye contact and lip-smacking related communication. The babies, even as young as two days old, are quick to pick up on this signaling and will imitate their mother’s lip smacking behavior, or even perform it independently for attention. Interestingly enough, after about a month of life young macaque stop this sort of communication as they become more and more mobile.
Ferrari thinks that, like humans, macaques can use facial expressions and other gesticulations to communicate the meaning of behaviors, emotion, and experiences. To test his hypothesis, Ferrari studied 28 macaques, 14 mothers and their corresponding infants, for 15 minutes a day every day for two months, and recorded their behaviors. Though it was previously known that macaques use lip smacking and eye contact to communicate, Ferrari’s study was the pioneer in recording frequency and environment of the behaviors. The results show a strong correlation between modern interactions and ancient ones known to have evolved over 30 million years ago in Old World monkeys. Think of a human mother over-exaggerating her facial expressions and voice inflection when talking to her child – a mother macaque seems to follow the same basic guidelines.
Other similar mother-baby communication discoveries have been made in chimpanzees. Like the macaques, young chimps will learn communication basics from the over-exaggerated signals their mothers send. However, chimps take part in joint attention, whereas macaques do not. Joint attention involves making inferences about what others are thinking, like a baby chimp following a mother’s gaze towards a particular object. Joint attention seems only to have evolved in animals with long stretches of early dependency on others, especially parents, and thus need to develop a more complex pattern of communication.
Link to article: http://dsc.discovery.com/news/2009/10/09/macaque-mama-baby-02.html
Posted by Bethany Rappleyea
Blog Revision
The article actually did mention that there was an evolutionary correlation. Human mothers often exaggerate their voice inflection/facial expressions in a way that very closely resembles the rhesus macaque and other old world monkeys. The general consensus of the scientific community states that humans evolved from old world monkeys.
The babies stop following the mother because they are more independent as they become more mobile, and are physically separated from their mother’s side. They have learned what they can from their mothers and use their knowledge to communicate with others. Chimps remain dependent on their mothers for a longer period then the macaques, and so they end up imitating the mother for a longer time.
The mother macaques exaggerate expressions of emotion, though because this study is in such a new field, I have been unable to find exactly which types of expressions they exaggerate. It seems implied that the emotions are pretty much of the positive reinforcement type, but I imagine they let their babies know when they are threatening or responding to some other negatively associated behavior.
It is interesting that as the young macaque become mobile, they stop this communicating with their mothers. Is this because at this time, they are basically independant and do not need parental care anymore?
ReplyDeleteIt is also interesting that mothers overexaggerate their expressions, just like humans do with babies. Is this an evolutionary connection?
Humans and monkeys are more alike than most people think!
-Tricia Carlson
This article is very interesting. Since I work in a lab with rhesus monkey's I have seen behaviors between a mother and her babies. The babies in the lab are older so they don't rely on their mother any more. They often communicate, but don't need to follow what the mother is doing. I wonder what stops them from following the mother?
ReplyDeletePosted by Samantha Babcock
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ReplyDeleteI think this is really interesting. I have observed rhesus macaques communicating with their mother, and they seem to be aware of extremely intricate facial signals. Which facial expressions did the monkeys make that were exaggerated? Did she also exaggerate different vocalizations, or threats?
ReplyDeletePosted by Heather Gore