New research from Duke University shows that visual cues -- such as images of people smoking -- may promote relapse among those trying to quit, MSNBC reported Jan. 6.

Scientists looked at scans of smokers' brains before and 24 hours after participants stopped smoking and were exposed to images of others smoking. Researcher Joseph McClernon and colleagues found increased brain activity in the dorsal striatum of subjects, which is responsible for automatic responses. This suggests that smoking cessation may be hampered by brain activity beyond a person's conscious control.

The brain becomes more sensitive to smoking cues after a person quits smoking, which helps explain why many ex-smokers relapse, McClernon said.

(How can I quit once and for all?)

"Only five percent of unaided quit attempts result in successful abstinence," McClernon said. "If we're really going to help people quit, this emphasizes the need to do more than tell people to resist temptation. We also have to help them break that habitual response."

The study was published online in the journal Psychopharmacology.