Human and Animal Communication
Human Language and Animal Communication
Every species communicates in some way, from the alarm calls of vervet monkeys to the song of birds. But is animal communication really the same thing as human language? Aitchison’s criteria of language features gives psychologists a checklist for comparing communication systems across species. If a system meets most of the criteria, it can be called a language; if it only meets a few, it is a more limited form of communication.
Aitchison’s criteria include semanticity, displacement, arbitrariness, productivity, cultural transmission, spontaneous usage, turn-taking, duality and structure dependence. Human language meets all of these; most animal communication systems only meet a few.
The Criteria Explained
Semanticity means that words carry a specific meaning that both speaker and listener understand. Displacement means language can refer to things that are not right in front of you — the past, the future, or things that may never happen at all. Arbitrariness means there is no natural link between a word and what it stands for — the word ‘dog’ does not look, sound or feel like a dog; the connection is agreed by convention.
Productivity (sometimes called creativity) is the ability to combine a limited number of words and grammar rules to create brand new sentences that have never been said before, and to understand sentences you have never heard. Cultural transmission means language is learned from the community around you rather than being fixed at birth — a child raised in a French-speaking home learns French, not an instinctive ‘human language’.
Spontaneous usage means humans can start a conversation whenever they choose, rather than only communicating as an automatic reaction to a stimulus such as danger. Turn-taking means conversation follows a pattern of one person speaking while the other listens, then swapping roles.
Duality (sometimes called duality of patterning) means language works on two levels: small, meaningless sounds combine into meaningful words, and those words combine into sentences. Structure dependence means sentences follow grammatical rules about word order — ‘the cat sat on the mat’ means something different from ‘the mat sat on the cat’, even though the words are identical.
Similarities Between Human and Animal Communication
Animal communication is not meaningless. Vervet monkeys use different alarm calls depending on whether the threat is a snake, a leopard or an eagle, allowing other monkeys to respond appropriately — this shows a basic form of semanticity, because each call maps onto a specific meaning. Bees perform dance movements inside the hive to indicate roughly where a food source is, and many bird species sing to attract mates or defend territory. In these examples, animal communication and human language share the basic function of passing meaningful information from one individual to another.
Animal communication can show semanticity (specific calls for specific dangers) and can serve social functions such as attracting mates or marking territory — but this does not mean animal systems meet all of Aitchison’s criteria.
Differences Between Human and Animal Communication
Most animal communication systems are missing several of Aitchison’s criteria. A vervet monkey’s alarm call cannot describe a leopard that was there yesterday, or one that might arrive next week — there is no displacement. Animal signals are usually a fixed, limited set that cannot be recombined into new meanings, so there is little or no productivity. Cultural transmission is also limited: many animal calls appear to be largely instinctive and consistent across the species, rather than learned from a particular community the way human languages differ from country to country.
Duality and structure dependence are also generally absent from animal communication. A bird’s song or a monkey’s call functions as a single, whole signal rather than being built from smaller meaningless units that combine according to grammatical rules. This is one of the clearest differences between animal signals and human sentences, which can be broken down into sounds, words and grammatical structures.
A strength of using Aitchison’s criteria is that they give psychologists a clear, structured way to compare very different communication systems, rather than relying on a vague impression of what counts as ‘language’. This makes the comparison more objective.
A weakness is that the criteria may be too strict, judging every animal system against a human standard. Some researchers argue this is unfair — an animal signal that meets only two or three criteria may still be a highly effective, sophisticated system for that species’ needs, even if it is not a full language by Aitchison’s definition. Comparing animal communication to human language may not always be a fair, like-for-like comparison.