Using brain scans to measure blood flow, British researchers discovered that a brain region known as the ventral striatum was more active when subjects chose unusual objects in controlled tests.

The ventral striatum is involved in processing rewards in the brain through the release of neurotransmitters like dopamine.

Scientists believe the existence of this age-old reward mechanism indicates there is an evolutionary advantage in sampling the unknown.

"Seeking new and unfamiliar experiences is a fundamental behavioral tendency in humans and animals. It makes sense to try new options as they may prove advantageous in the long run," said Bianca Wittmann of the Wellcome Trust Centre for Neuroimaging at University College London.

Being daring, however, also carries risks. Some choices could be dangerous and, in the modern world, selecting the new may, for instance, make consumers susceptible to marketing hype.

The positive feedback system in the brain could also contribute to some common vices.

"In humans, increased novelty-seeking may play a role in gambling and drug addiction, both of which are mediated by malfunctions in dopamine release," said Nathaniel Daw, now at New York University, who also worked on the study.

The findings were published online in the journal Neuron.

At the "Buns and Guns," the chefs wear military helmets, the food is wrapped in camouflage paper and the advertising slogan is "a sandwich can kill you."

The fast food eatery with a tongue-in-cheek military theme opened three weeks ago in Beirut's Hezbollah-dominated southern suburbs and is drawing in residents proud of the Shiite militant group's battlefield successes.

Done up like a military outpost, the restaurant is located in the heart of a neighborhood heavily pounded by Israel during its 2006 war with Hezbollah, which fought the Israeli military to a standstill.

Neatly stacked sandbags cover the exterior, while the inside is festooned with camouflage nets, defused mortar shells and live ammunition. Employees in military uniforms serve meals to the taped sounds of gunfire as "background music."

"We thought at the beginning that it was a weapons store but later we discovered that it was actually a fast food restaurant," said customer Amr Nahas as he ordered a "magnum," a grilled chicken sandwich, with a side order of "grenades" or potato wedges.

"The sandwiches are really delicious," he added.

The restaurant's founding comes during a particularly tense period in Lebanese politics. Fighting between supporters of the government and the Hezbollah-led opposition in May killed 81 people and raising fears of a renewed civil war. It ended only after a political deal that gives Hezbollah and its allies a strong portion of a unity government.

But the restaurant's owners say the military motif has nothing to do with the security situation in Lebanon, but is meant to attract customers.

"The idea came before all the clashes that happened in Lebanon," co-owner Ali Hamoud told Associated Press Television News on Tuesday. "But in the end, (the fighting) helped in advertising the restaurant."

While many Lebanese have been sickened by the renewed fighting — including clashes Monday in the north that claimed another eight lives — many in the Hezbollah strongholds of south Beirut express pride in the movement's strength and gains.

"Establishing a military restaurant is a new fancy idea — there are people who like anything that deals with weapons," said one employee, who declined to give his name because his boss hadn't given him permission to speak to the media.

He said the restaurant had no direct connection with Hezbollah. But it could not operate in the heart of Hezbollah's south Beirut stronghold, where the guerrilla group's word is law, without its blessing — and Hezbollah's Al-Manar TV ran a story about the restaurant, a sign of the movement's support.

Customers enter the restaurant under a sign bearing the restaurant's name — in English — and the slogan, "a sandwich can kill you," a reference to the large portions.

The glossy camouflage menus feature burgers with names like "the mortar" and "the 155 mm howitzer," while grilled chicken sandwiches can be a "magnum" or a "rocket-propelled grenade." Lebanon's most common and popular weapon, the AK-47 Klashnikov assault rifle, is a beefsteak sandwich served in long baguette-style bread.

A pizza topped with peppers, onions, mushrooms, olives, corn and tomatoes is rather disturbingly named Claymore, referring to the devastating anti-personnel mines.