Final answer:
Producer Jimmy Miller encouraged The Rolling Stones to incorporate elements of African American music into their sound, which helped blur racial lines.
Step-by-step explanation:
Producer Jimmy Miller encouraged The Rolling Stones to embrace and incorporate elements of African American music into their rock and roll sound. This was a significant shift that helped blur racial lines and bring together both black and white audiences. Miller's production style and influence can be heard in their albums like 'Sticky Fingers' and 'Exile on Main St.', which featured blues, soul, and funk influences.