Researchers studying bonobos have found that the closest living relatives of humans in the primate world are capable of communicating in a means similar to how human infants do it.
According to a study published in the journal Peer J, bonobos "peep," which are short, high-pitched sounds produced while the mouth is closed. Peeps are produced in various situations and can have positive, negative and neutral meanings depending on circumstances. Researchers looked into the acoustic structure of peeps and found that calls made under positive and neutral contexts are not that different from each other.
Because peeps made are similar regardless of the emotional context they were produced for, this is what led researchers to associate sounds bonobos make with those that human infants produce. Before language development unfolds, human babies turn to producing calls known as protophones regardless of their emotional state.
Having observed the similarities between bonobos and human babies, the researchers felt it was too early to conclude that peeps was a unique human ability, most especially when no studies have been carried out to observe the great apes. Rather, the type of communication can be considered as a transition from "functionally fixed animal vocalizations" to human vocalizations.
Linguists have long argued that language is a behavior belonging solely to humans. Though they may have similarities, animal communication still falls short of matching human language in a number of ways. For instance, humans are in possession of an innate universal grammar that only they can understand, readily demonstrated in similarities in languages across societies. Though all animals communicate, they do not share a common grammar that will facilitate understanding across species.
To quantify communication as language, various linguists have come up with lists of criteria to judge interactions with. Charles F. Hockett, an American linguist, also created a list of his own, running down 13 "design-features" that language must have. According to him, the following must be met for communication to be deemed as a language:
- Vocal-auditory channel (sounds released from the mouth and heard by the ears)
- Broadcast transmission and directional reception (requires a knowledge of where a sound is coming from)
- Rapid fading (short-term signals)
- Interchangeability (all sounds understood must be produced)
- Total feedback (the sender hears what they sent)
- Specialization (signal specifically produced for communication)
- Semanticity (sound and meaning have a fixed relationship)
- Arbitrariness (sound and meaning have an arbitrary relationship)
- Discreteness (discrete units can be used to build language)
- Displacement (communication involving events or topics distant in space or time)
- Productivity (language as an open system producing infinite messages)
- Traditional transmission (each generation learns the communication system from the ones before them)
- Duality of patterning (numerous meaningful signals)
No means of animal communication has been established to have met Hockett's criteria for language. Despite the similarities in how humans and apes communicate, human language remains unique based on the items on the list.
Photo: Tim Sheerman-Chase | Flickr
