I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "The latest study using magnetic resonance imaging (MRI) to humans and dogs together proved that dogs have same response to voices and use the same parts of the brain as humans to do so. This gives dogs the ability to recognize emotional human sounds, making them friendly social pets to humans."? 

What is the main idea of the passage?