For animals that operate in packs – such as wolves (Canis lupus) and, ancestrally at least, their close relatives, dogs (Canis familiaris) – cooperation is an important trait. However, its evolutionary origin is obscure.

Researchers led by Rachel Dale from the University of Veterinary Medicine in Vienna, Austria, decided to investigate whether dogs – the product of thousands of years of domestication – had retained, or even improved, the ability to consider the needs of pack members.

In play were two competing hypotheses. One suggested that wolves need to be cooperative – “prosocial”, in the jargon – because of their wild, pack-hunting lives, while domestic dogs, dependent on human agency, do not.

The other held that traits such as intelligence and cooperation with both humans and other dogs are precisely the things that have been deliberately amplified by the domestication process, and so dogs should be more prosocial than their wild relatives.

To find out which idea was right, Dale and colleagues conducted a series of experiments.