Vocal development is extremely vital in any species, as it is something that is used throughout one’s lifespan. Vocal development is developed through a host of tactics. Human vocal development is partially dependent on learning by imitation through social feedback between parents and caregivers (Gultekin, 2017). There have been recent studies to show that this is true as well within Marmoset monkeys.
In a study, researchers recorded 13,582 vocalizations of five subadult Marmoset monkeys that were provided visual and auditory contact with potential caregivers. The monkeys were born from the same parents, but from two different litters. The first litter consisted of three monkeys that had direct contact with their parents within the first 3 postnatal months. These monkeys lacked direct parental feedback after the third month. The second litter consisted of two monkeys who were still grouped with their parents. Both of the litters were in similar conditions, but only differed when it came to direct or indirect parental feedback after three months. To test vocal development, the subjects were isolated in a small cage and were given direct visual and auditory contact with caregivers. In this condition all five of the monkeys showed a variety of adult call types. It was found that monkeys that had limited parental feedback around the age of 7 months still produced infant vocalization at the age of 13 months. Vocal behavior was quantified by comparing call distributions and the order of uttered calls within the recording session. It was found that limited parental feedback monkeys showed infant-specific distribution of call parameters. For example, higher peak frequencies and shorter durations in relation to normal raised monkeys.
The results showed that the vocal behavior of the monkeys with limited parental feedback differs from normal raised monkeys. This means that there was a role of social feedback on primate vocal development. The results mirror previous research that suggested that basic call structure is innate and does not have to be learned through auditory or social feedback. The results from this study show the vital role of parental feedback on vocal development after infancy. The limited parental vocal feedback may not have been the sole reason for changes in vocal behavior among the Marmoset monkeys. Environmental and psychological factors might have caused the vocal abnormalities in these animals. As we can see vocal behavior is important in infancy as well as beyond.
References
Gultekin YB, Hage SR. Limiting parental feedback disrupts vocal development in marmoset monkeys. Nat. Commun. 2017;8:14046. doi: 10.1038/ncomms14046.
Gabrielle Moore
November 13, 2017 — 5:20 pm
I think that this study is so interesting, as humans have learned that it’s important for human parents to give feedback to their offspring as well for their social development to be considered normal. I’d be curious to see whether other researchers have studied other factors of parental feedback such as nonverbal cues that play a role in infants’ behavior.