Background: Anthropologists believe the most significant benefit would have been the use of dogs' robust sense of smell to assist with the hunt. The relationship between the presence of a dog and success in the hunt is often mentioned as a primary reason for the domestication of the wolf, and a 2004 study of hunter groups with and without a dog gives quantitative support to the hypothesis that the benefits of cooperative hunting was an important factor in wolf domestication.
Question: What year was research completed to demonstrate humans benefited by having dogs hunt with them?
Answer:<extra_id_0>.
<extra_id_0> 2004<extra_id_1>