Your example is needlessly bleak, but in general: yes, we're a social species and being able to process multiple speech streams seems obviously pretty important in many social contexts involving more than two people.
And in general our brains differ significantly from that of a chimpansee. Human brains push neuron density to to absolute limit within the animal kingdom and have unique evolutionary adaptations that allow for it. As a result our species also has mental health disorders unique to us that seem to be cause by the neurons being pushed past that limit.