(CNN) -

Here's a roundup of five medical studies published this week that might give you new insights into your health. Remember, correlation is not causation -- so if a study finds a connection between two things, it doesn't mean that one causes the other.

You'll eat less watching 'Charlie Rose'

Most of us eat mindlessly when we sit in front of the TV. But what we're watching may affect how much we eat, according to a research letter published in JAMA Internal Medicine on Monday.

Researchers selected 94 graduate students to participate in a small study. They gathered in groups of 20 to watch 20 minutes of TV. A portion of the students watched the fast-paced action movie "The Island," some watched "The Island" but without sound, and a third group watched the interview program "Charlie Rose."

All the groups were given M&Ms, cookies, carrots and grapes and told they could eat as much as they wanted. The researchers weighed the food before and after to determine how much had been eaten. They found participants watching "The Island" with sound ate 65% more calories than those watching "Charlie Rose." Even the group watching the movie without sound ate more than those watching the slower-moving talk program.

The study authors concluded that more distracting TV increases food consumption, though other factors like anxiety, agitation and stimulation may have played a role.

Americans are eating healthier, if they can afford it

As the rich get richer, they get healthier, too, a new study published in JAMA Internal Medicine this week suggests.

Scientists looked at the diets of 29,124 adults between 1999 and 2010. They found Americans' diets improved over that decade, especially if they were in a higher socioeconomic bracket.

The poor, though, ate poorly. That was due in large part to the fact that healthy food is expensive, and because they often lived in neighborhoods that didn't have a grocery store nearby.

While researchers found that American diets did improve in this period, all things are relative. People still didn't eat enough fruits and vegetables, no matter how much money they made. The biggest improvement in people's diets came from eating less trans fat. There has been a big push from the government to make manufacturers leave the substance off the menu.

Plants make us happier at work

Sleek modern design may not make you very productive, a new study from the Journal of Experimental Psychology finds.

Researchers looked at the impact of introducing plants into a "lean office." The employees worked in the United Kingdom and in the Netherlands.

Workers in the offices with the plants reported more general happiness on the job. They seemed to feel they could concentrate more. They reported feeling that their air quality was better.

Just by introducing the plants, observed productivity went up 15%.

Experiences make you happier than possessions

Money can buy you happiness if you spend your hard-earned cash on an experience rather than a possession, new research shows. The study, "Waiting for Merlot," ran in the journal Psychological Sciences.

Researchers looked at the overall happiness level of people who bought experiences like trips or concert tickets and found that they were a lot happier than people who bought things. Those people were happier at all phases of their purchase -- in anticipating the trip, at the concert, and afterward while thinking about the great night out that they had.

Even standing in line, scientists found people were happier waiting to get concert tickets than they were waiting in line to buy items.

The weed vs. alcohol debate continues

What's worse: alcohol or marijuana? Scientists wanted to know the answer to that question, particularly as it pertained to teens.

Looking at data in the Monitoring the Future Study, they examined the answers high school seniors gave to questions about the consequences of their drug and alcohol use.

The study, which ran in the American Journal of Drug and Alcohol Addiction, found that children who used marijuana had a harder time overall. Their drug use hurt their relationships with teachers and with managers at their after-school jobs.

Marijuana use made them less successful in school. It sapped their energy and interest in regular activities.