What makes us human?

Communication, culture, and cooperation is not only seen in humans. These exist also in other animals but in different forms and degrees.  

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Meaningless sounds to meaningful stories 

All living beings communicate. However, human language is arguably the most complex form of communication. Language can be spoken, written, and signed and allows both complex cooperation and the transmission of culture across time (generations) and space (cities, countries, continents).  

Complexity of vocalization/language 

Many animals can also name things from their environment with calls. Humans can also name foreign and abstract things such as dinosaurs, satellites, or time.

Songs and stories 

In some species meaningless sounds can also be combined into larger meaningful complex structures – such as songs. Songs are common in birds, whales, but also in some primate species such as gibbons. 

A growing number of species have also been shown to combine meaningful calls, such as alarm calls or food calls, together into larger mini-phrases. However, the capability to form long and complex sentences as in human language is currently absent. 

Chimpanzees for example can combine 2-calls communicating the presence of a threat and the need for help into a larger meaningful structure:

• Call A: "Watch out"
• Call B: "Come here"
• Call A + B: "Watch out" + "come here"

Culture and tools 

Culture is innovations spread and maintained between generations by social learning, e.g. tools, customs, language, art… 

Human culture is cumulative …

… which means that more complex traditions arise by elaboration on earlier ones. There is only minimal evidence for cumulative culture in nonhuman species, but it characterizes humans. Examples of cumulative culture:  smart phones, spaceships, motorways/traffic… 

Learning and teaching 

Cumulative culture requires more precise social learning mechanisms involving teaching and language.

Chimpanzees and other non-human apes have been shown to learn their cultural skills, such as tool use, by observing skilled individuals. 

Common benefit 

Cooperation is when multiple individuals work together for common benefits. It is widespread across the animal kingdom.

Cooperation can take place within species...  

…or between species...   

In some cooperative tasks multiple individuals can benefit immediately. 

Whilst other tasks rely on reciprocity - one individual benefits now and the other is likely to benefit in the future. This type of co-operation requires more complex cognitive processes, such as a good memory, and is therefore rarer in the animal kingdom. 

Having strong and reliable social relationships can help facilitate a broader range of cooperative activities as it increases the chance of reciprocity in the long-term. These delayed benefits can also take on a different form e.g. receiving protection or social support from past grooming partner.

Range of cooperation 

Cooperation in humans is particularly unusual because of the wide range of cooperative activities we engage in. Almost everything we do involves cooperation, and these activities are facilitated by the diverse kinds of relationships we have. 

It is not only the range of cooperative activities that makes human cooperation unusual but also their spatial and temporal scale. 

Our communicative abilities and complex social relationships are believed to have been hugely important in enabling the range and scale of cooperation found in humans. 

Researchers at the University of Zurich have been studying human evolution for over 125 years. The focus of research has changed over the years but the drive to understand the uniqueness of our own species and to protect other species that help us in this endeavour never has.