Senator Scott Brown campaigned door to door last month in Chelmsford.

His Democratic challenger, Elizabeth Warren, blazed onto the national consciousness as a Wall Street watchdog and consumer advocate and has emerged as a candidate with crowd appeal.

Warren talked with Rachel Majorowski in Boston.

Senator Scott Brown greeted shoppers outside a Stop and Shop in Attleboro in February.

Retail events like these are Brown’s forte, showcasing the approachability that helped propel him to an unlikely victory.

Brown dashed into the supermarket to make some purchases.

Warren visited Cafe Azteca restaurant in Lawrence in February.

Brown (left) met Tim Brennan, Charlie, 4, and Henry, 9 months, in Chelmsford.

Warren greeted Ralph Mazzeo and his dog, Mazy, on Castle Island.

As a candidate, Warren has emphasized her natural feel for people, and her modest upbringing in Oklahoma. “I am amazed when I meet some people in politics and I think: ‘You don’t actually like people. How did you end up in this business?’ " she said.