It s almost the end of June. Have you taken a vacation yet? Are you putting it off? Well, don t. I don t mean to alarm you, but science is pretty clear on this point: It s time you got the hell out of town.

We don t have time to go through every reason vacations are good for you. So, let s just take a look at the top five:

You ve Already Procrastinated

If there s one thing we know about humans, it s that they procrastinate. I should have written this column weeks ago. What we ve also learned, though, is that they procrastinate not just when it comes to negative things, but when it comes to positive things, as well.

In a study of this phenomenon forthcoming in the Journal of Marketing Research, Suzanne Shu of UCLA and Ayelet Gneezy of UC San Diego found that people will delay even visiting local landmarks of the very cities in which they live. The researchers stopped 199 passing pedestrians on the street in London, Chicago and Dallas (some locals, some tourists), and asked them which local landmarks, and which landmarks in seven international cities, they had visited. What they found was that the average two-week visitor to a city has seen more of the local landmarks than someone who has lived in that city for a year.

If they were about to move away, 2) If a friend or relative was in from out of town (60% of visits to landmarks, according to the city residents, occurred in the presence of out-of-town guests).

Much as with a gift card, it sometimes takes a deadline to make us have fun. So, treat the world like your city and pretend your cousin is in from Des Moines.

You ll Regret Not Having More Fun

While being too reluctant to indulge our impulses is not particularly well-known as a modern malady, there are still those who suffer from it and there are still researchers who study it. Being too short-sighted, in the economic sense, is called myopia; the opposite condition, focusing too much on the future, has been dubbed hyperopia (the medical term for farsightedness).

To test people for behavior consistent with hyperopia, Ran Kivetz of Columbia University and Itamar Simonson of Stanford University looked at how college students felt about how they had spent their winter breaks. Specifically, they asked students at an East Coast university how they felt about the balance of work versus play over their breaks. Right after break, the students chief worry was that they hadn t done enough studying, done enough work, or saved enough money. A year later, though, students were more worried that they hadn t traveled enough or had enough fun over their breaks. The effect was magnified for alumni returning for their 40th reunion: When posed the same question about how they d spent their breaks, they were really ticked off they d wasted any time on books.

Now, this doesn t mean everyone should evaluate every decision as if he or she were on his or her deathbed. (You may never regret that you didn t spend more time taking out the garbage, but you will regret when a herd of rats starts conducting military exercises on your couch.) But it should at least remind you that your priorities today won t necessarily be your priorities tomorrow and the memories of a vacation will probably mean a lot more to you than whatever s going on at the office.

Vacation Breaks the Stress Cycle

At least in rats. Experiments in rats published last year in Science found that chronic stress (for rats, that s getting shocked a lot and, depending on where you work, maybe that s the case for you, too) caused the parts of the rats brains involved in executive decision-making and goal-oriented behavior to shrivel, while regions related to habit formation grew. It s thought this stress response may behave similarly in humans with stress making us more likely to rely on habit.

Good news, though (at least for the rats): Four weeks vacation brought their brains back to normal. Too bad not too many people in the United States have that many vacation days.

Nature Is Restorative

Even without a full four weeks, though, it seems that nature has some pretty significant effects on how we feel and how we treat our fellow members of the rat race.

In a study published in Psychological Science in 2008, researchers found that exposure to nature such as a walk in the woods increased cognitive processing on what s called a backwards digit-span task (listening to a list of digits, as long as nine numbers, and then repeating the numbers backwards).

In another study, published in 2009 in the Personality and Social Psychology Bulletin, researchers at the University of Rochester reported the results of a study in which they found that mere exposure to images of nature made people more generous with money in a laboratory trust experiment.

Travel Boosts Creativity

Of course, you don t have to head to the country, if you re more of a city rat. The simple act of traveling, especially abroad, has been found in numerous studies to enhance creativity. For instance, one recent study found that students who ve traveled abroad are about 20% more likely to solve a standard creativity test (a problem where participants are asked to fasten a candle to a corkboard) than students who haven t.

So, get on a plane. Your brain needs it.