Why Humans Have Thousands of Tools and Other Animals Do Not

You may be familiar with the debate. Some biologists, anthropologists, and psychologists claim that several nonhuman animal species have culture. They point to two kinds of evidence to support their claim of animal culture.

First, some animals communicate with each other—and language is a cultural product. Bees perform a waggling dance to indicate the location of a food source. Humpback whales emit feeding calls. Some apes have learned to communicate with humans using sign language. A grey parrot named Alex had a vocabulary of 100 words and could identify simple objects.

Second, some animals use tools—and tools are cultural products. The best-known examples of animals using tools are chimpanzees that use twigs and sticks to “fish” for tasty crawling treats, sea otters that use rocks to crack open shellfish, and dolphins that use sea sponges to protect their beaks as they search for food along the seabed.

I’ve never understood why scholars have invested so much time and effort arguing over the existence of animal culture. I feel like they’ve walked right past the main event and gotten lost in a relatively meaningless sideshow.

Mind the Gap

The crucial question is not whether some animals use tools and communicate with each other. They do. The crucial question stems from the fact that there’s a huge gap between humans and other animals when it comes to language and tool use.

To the extent that some animals communicate, they do so in a very simple way that lacks syntax and grammar, two hallmarks of language. Humans, on the other hand, lead lives that overflow with language. We know and use thousands of words every day. We easily add new words to our vocabulary—and some of us speak more than one language.

Humans use language to ask questions. (No other animal has ever asked a question.)[1] We invent new terms: brat summer, bromance, rizz, sick burn, twerking, and more. Most importantly, we use symbolic versions of language to read and write books, tweets, instruction manuals, and posts like this one. (No other animal has ever read or written anything.)

Much the same can be said of tool use. Humans don’t have just one or two tools at their disposal. We have thousands of tools—hammers, jackhammers, can openers, can crushers—the list is almost endless. Some of our tools are so complex and technologically sophisticated that we don’t even think of them as tools anymore. Consider automobiles, televisions, submarines, and spaceships.

All of this leads to a conclusion that seems self-evident: If animal culture exists, it is an extremely limited, intellectually and technologically impoverished version of what we call human culture. The evidence is everywhere we look. Universities, symphonies, and supermarkets. Book clubs, hospitals, and art galleries. Other animal species have none of these.

In my view, the existence or nonexistence of animal culture is not a very interesting question. A much more interesting question is this: Why do humans have hundreds of millions of cultural products and other animals have hardly any?

Let’s ask a narrower, more manageable version of the question. Why do humans have thousands of tools and other animals have only a few?

One approach is to focus on the relevant physiological differences between humans and other animals. Humans, for example, have large brains and opposable thumbs. Most animals do not, which puts them at a disadvantage. Thinking of the issue in that way seems fine, as far as it goes, but I believe a better answer comes to us from comparative psychologist Michael Tomasello at Duke University.

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Cultural Learning and the Ratchet Effect

At the risk of oversimplification, Tomasello and his colleagues (1993, 2001, 2009) argue that humans are unique in their ability to create cultural products such as tools. Compared to nonhuman animals, we are exceptionally talented at learning from one another, in part because we can take the perspective of another person and recognize their intentions. Other animals cannot do this.

Humans are also able to transmit cultural products with high fidelity. In other words, we’re gifted imitators and replicators. We can see something (a gesture or diagram) or hear something (a new word or melody) and produce an exact or nearly exact copy. High fidelity is necessary for the successful accumulation of cultural knowledge. A cultural product that is replicated with low fidelity—a joke that’s mangled in the retelling, for example—usually ends up in the dustbin of history.

Tomasello’s theory of cultural learning includes another key concept called the ratchet effect. Cultural innovations can be shared with others. When a person makes a better mousetrap or some other technological improvement, the advance can leap from one human mind to another by means of language, imitation, and social learning. As a result, technological progress does not slip back to an earlier stage. It moves up and forward, one small step at a time.

Instances of the ratchet effect can be found throughout human history. The first hammer was a handheld rock, then a rock tied to a stick, and eventually, a molded piece of steel fitted to the end of a sculpted wooden or plastic handle. The first recorded music was inscribed on metal cylinders, followed by vinyl records, magnetic tapes, and eventually digital files in computers.

To my knowledge, no instance of the ratchet effect has ever been observed among nonhuman animal species. Chimpanzees have used twigs to fish for termites and ants, but they haven’t made any lasting improvements to the tool itself or how the tool is used.

In short, humans have created and accumulated a huge store of cultural knowledge and products because they (we!) are superb imitators and high-fidelity replicators. Other animals are not.

[1] The grey parrot Alex’s trainer, Irene Pepperberg, reported that Alex once asked, “What color?” when he saw himself in a mirror.