You know that guy at work; the one who comes in early, leaves late and never eats lunch because he is just so driven? Well, maybe he can't help himself, likewise for your colleague who hardly works at all.

Researchers at Vanderbilt University say that when it comes to how hard somebody works to earn a living (or not), the difference may be — at least in part — a matter of brain chemistry. Writing in the Journal of Neurosciences, Vanderbilt scientists used imaging technologies to determine that an individual's willingness to work hard to earn money is strongly influenced by the chemistry in three specific areas of the brain.

Hard-charging, go-getters, they say, had high levels of dopamine, a neurotransmitter known to play a role in reward and motivation, in the striatum and ventromedial prefrontal cortex portions of the brain. Conversely, slackers had high dopamine levels in the anterior insula, a part of the brain associated with emotion and risk perception.

The fact that dopamine appears to produce opposing effects in different parts of the brain complicates things, but the scientists say it might eventually help them improve or tease out new treatments for neurological conditions characterized by decreased motivation, such as attention-deficit disorder, depression and schizophrenia.

BODY OF KNOWLEDGE

The average duration of a single blink of the human eye is 0.3 seconds. The average person blinks 25 times per minute, or about 13,140,000 blinks per year.

GET ME THAT. STAT!

When it comes to smoking weed, New Zealand tops the list, according to the OECD. Just over 22 percent of the population reportedly smokes marijuana. Australia is second at 17.9 percent, followed by the United States (12.3 percent), United Kingdom (9 percent), and Switzerland (8.5 percent)

LIFE IN BIG MACS

One hour of sitting or singing in church burns 102 calories (based on a 150-pound person) or the equivalent of 0.1 Big Macs.

DOC TALK

Domino transplant — an organ transplant in which a donor's heart and lungs are transplanted into a second person whose heart, in turn, is transplanted into a third person

PHOBIA OF THE WEEK

Kopophobia — fear of fatigue.

NEVER SAY DIET

The Major League Eating speed-eating record for rice balls is 20 pounds in 30 minutes, held by Takeru Kobayashi.

BEST MEDICINE

During a physical exam, a doctor remarked on a new patient's extraordinarily ruddy complexion. The patient replied, "High blood pressure, doc. It comes from my family."

"Your mother's side or your father's," asked the doctor.

"Neither," replied the patient. "My wife."

OBSERVATION

"A doctor's reputation is made by the number of eminent men who die under his care."

— Irish playwright George Bernard Shaw (1856-1950)

CURTAIN CALLS

Robert Williams, a worker at a Ford Motor Co. plant, became the first known human to be killed by a robot when, in 1979, he was struck in the head by a swinging arm of a one-ton factory robot.

To find out more about Scott LaFee and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.