Native American cookbooks and college directories have not had much impact on the Senate race in Massachusetts.

A new poll from Suffolk University/7NEWS finds Sen. Scott Brown (R) and Harvard Law Professor Elizabeth Warren (D) in a dead heat, 48 percent to 47 percent. Suffolk last polled the race in February and found Brown had a nine-point lead.

Only five percent of voters are undecided.

Democratic Senate candidate Elizabeth Warren speaks to area residents while at a campaign event in Roxbury, Massachusetts, Tuesday, April 17, 2012. (Melina Mara/THE WASHINGTON POST)

Seventy-two percent of likely voters were aware of the controversy concerning Warren’s heritage and whether she used it to advance her career. Brown’s campaign has been hammering the issue for weeks, calling on Warren to release her academic records.

Of those who were aware of the story, 49 percent said Warren was telling the truth about being part Native American; 28 percent said she was not telling the truth; and 23 percent weren’t sure. Forty-one percent thought Warren benefited by listing herself as a minority in law school directories, while 45 percent said she did not.

But 69 percent of likely voters said that Warren’s Native American heritage listing is not a significant story, while 27 percent said that it is.

Voters were similarly unmoved by Warren's push to tie Brown to Wall Street. Only 33 percent agreed that a vote for Brown is a vote for Wall Street. They were split on whether her should return campaign donations from JP Morgan Chase employees.

That echoes the presidential race, where Obama’s gay marriage support and allegations that Romney bullied another student as a teen have had little impact.

Brown’s popularity went up from 52 percent to 58 percent over the past few months while his unfavorable rating stayed steady at 28 percent. Warren’s favorability jumped eight points, from 35 percent to 43 percent, but her unfavorable rating also went up, from 28 percent to 33 percent.

Warren has been on television longer than Brown, but the senator has been airing regular radio ads. A ban on outside ads has kept negative ads at bay — something that may have helped Warren in particular this past month.