Republican presidential candidate Ben Carson said his campaign plans "alterations" to respond more aggressively to challenges to his life story and foreign policy expertise that have created a negative impression of him with some voters.
Carson, who earlier this year led some national polls among 2016 Republican hopefuls, said on the CBS "Face the Nation" broadcast on Sunday that his campaign needs to "forcefully inject" its responses to attacks that have harmed his standing.
"We have kind of taken a nonchalant attitude," Carson said. "That's the wrong thing to do, so you will see much more aggressiveness in that region."
Click through images of Ben Carson on the campaign trail:
Ben Carson on the campaign trail
Ben Carson vows campaign 'alterations' to defend against attacks
MT. AYR, IA - JANUARY 22 : Republican presidential candidate Ben Carson is introduced during his 'Trust in God Townhall' campaign stop January 22, 2016 in Mt. Ayr, Iowa. Carson, who is seeking the nomination from the Republican Party is on the presidential campaign trail across Iowa ahead of the Iowa Caucus taking place February 1. (Photo by Joshua Lott/Getty Images)
Ben Carson, 2016 Republican presidential candidate, speaks during a Liberty University Convocation in Lynchburg, Virginia, U.S., on Wednesday, Nov. 11, 2015. As retired neurosurgeon Carson has risen in the polls, media reports have revisited his accounts of acts of violence as a child, a key part of the redemption story he discusses on the campaign trail. Photographer: Andrew Harrer/Bloomberg via Getty Images
PALM BEACH GARDENS, FL - NOVEMBER 06: Republican presidential candidate Ben Carson speaks to the media before speaking at a gala for the Black Republican Caucus of South Florida at PGA National Resort on November 6, 2015 in Palm Beach, Florida. Carson has come under media scrutiny for possibly exaggerating his background and other statements he has made recently. (Photo by Joe Raedle/Getty Images)
DES MOINES, IA - AUGUST 16: Republican presidential hopeful Ben Carson (L) eats a piece of pizza while touring the Iowa State Fair on August 16, 2015 in Des Moines, Iowa. Presidential candidates are addressing attendees at the Iowa State Fair on the Des Moines Register Presidential Soapbox stage and touring the fairgrounds. The State Fair runs through August 23. (Photo by Justin Sullivan/Getty Images)
LAKEWOOD, CO - OCTOBER 29: Republican presidential candidate Ben Carson speaks during a news conference before a campaign event at Colorado Christian University on October 29, 2015 in Lakewood, Colorado. Ben Carson was back on the campaign trail a day after the third republican debate held at the University of Colorado Boulder. (Photo by Justin Sullivan/Getty Images)
WASHINGTON, DC - SEPTEMBER 25: Scenes around the the Value Voters Summit on September 25, 2015 in Washington DC. Republican presidential candidate Ben Carson takes the stage at the event. Dr Carson speaks to the media after the speach. (Photos by Charles Ommanney/The Washington Post via Getty Images)
Attendees wait for Ben Carson, 2016 Republican presidential candidate, not pictured, to arrive during a campaign stop at the birthplace of the Michigan Republican Party in Jackson, Michigan, U.S., on Wednesday, Sept. 23, 2015. Carson, the third candidate in the Republican race to have never held elected office, saw his numbers drop following the debate last week. Photographer: Luke Sharrett/Bloomberg via Getty Images
Ben Carson, 2016 Republican presidential candidate, listens as he attends a service at Maple Street Missionary Baptist Church in Des Moines, Iowa, U.S., on Sunday, Aug. 16, 2015. Carson will be speaking at the Iowa State Fair, which is expected to host 18 presidential candidates and runs until Aug. 23. Photographer: Daniel Acker/Bloomberg via Getty Images
CLEVELAND, OH - AUGUST 06: Republican presidential candidate Ben Carson participates in the first prime-time presidential debate hosted by FOX News and Facebook at the Quicken Loans Arena August 6, 2015 in Cleveland, Ohio. The top-ten GOP candidates were selected to participate in the debate based on their rank in an average of the five most recent national political polls. (Photo by Chip Somodevilla/Getty Images)
Ben Carson, 2016 Republican presidential candidate, eats a slice of pizza as he tours the Iowa State Fair in Des Moines, Iowa, U.S., on Sunday, Aug. 16, 2015. In a Sunday interview with Fox News, Carson doubled down on his assertion that a speech given by President Barack Obama intended to sell the American public on his nuclear deal with Iran contained 'coded innuendos employing standard anti-Semitic themes.' Photographer: Daniel Acker/Bloomberg via Getty Images
Discover More Like This
BACK TO SLIDE
Carson said he should have responded sooner to suggestions in the media of inaccuracies and embellishments in his 1990 autobiography, "Gifted Hands," which chronicled the candidate's path from inner-city Detroit kid to world-renowned neurosurgeon, as well as the characterization of his foreign policy understanding as limited.
Capitalizing on enthusiasm for political outsiders in this year's presidential campaign, Carson, 64, vied with billionaire Donald Trump for front-runner status throughout the summer and into fall. His momentum has ebbed in recent weeks, as Senator Ted Cruz of Texas has gained support among religious conservatives who form the core of Carson's support, and Trump continues to dominate headlines.
Trump leads the Republican field with 37 percent support, with Cruz second at 18 percent and Senator Marco Rubio at 11 percent, according to an average of recent polls compiled by Real Clear Politics. Carson was in fourth place, with 9 percent support. In states that will hold the nation's first two nominating contests, Carson is running fourth in Iowa and seventh in New Hampshire.