Though few of us are aware of it, subtle cues in our environment have a striking effect on the decisions we make, the opinions we form, the actions we take—and on those of the people in charge of our fates. Just ask Adam Alter. As he points out in his new book, Drunk Tank Pink: And Other Unexpected Forces that Shape How We Think, Feel, and Behave, even something as simple as the color of a room can affect our behavior. In the late 1970’, Canadian psychologists discovered that a Pepto-Bismol hue known as Drunk Tank Pink had a miraculous ability to calm down hyperactive school children; after investigating further, they found that adults who merely looked at the color were rendered virtually incapable of aggressive behavior, at least temporarily. And when a Seattle jail painted its cells—or “drunk tanks”—the same color, rates of prisoner violence plummeted. So guess what football coaches who heard about these findings decided to do to visiting locker rooms?

Alter, an assistant professor of marketing at New York University’s Stern School of Business, talked to Medium about how the world around us, um, colors what we think and do in all sorts of ways that call into the idea of free will into question.

Q: As a former dating columnist, I found one of the most striking things in your book your discussion of the color red—which has a remarkable effect on the romantic brain. One study found that men spend more money on women who wear red on a date, for instance. Why does red make us feel so lusty? Does it have something to do with being the color of blood?

A: Yes, red seems to derive much of its power from its association with blood. When we’re attracted to someone, our blood vessels dilate and our skin blushes red—but red clothing, lipstick, rouge, and other forms of reddening make-up also subtly convey the message that we’re romantically interested.

Lower order animals show the same effect—the dominant members of many bird and ape species have particularly red faces or especially striking red feathers or facial features.

Red is a sign of virility, strength, and romantic interest.

As you mentioned, there’s plenty of evidence that men and women find potential mates more attractive when those people are wearing red—or even when they appear in a photograph with a red border. Men indicate that they’ll be more willing to spend more on a date when the women in the picture is wearing red than when she’s wearing a shirt of another color. In one experiment, female hitchhikers were more likely to be picked up by male drivers, but not female ones, when they were wearing red t-shirts rather than shirts of one of several other colors.

Q: So colors that other people wear informs our impressions of them. But what other people are wearing—and doing and announcing on Facebook—also informs our impressions of ourselves. In your book, you talk about how much our estimations of our own happiness and self-worth depend upon our perceptions of how happy and successful others are. It’s an instinct that works against me, personally—I’m always thinking about how I don’t measure up. But in your book, you talk about how the tendency to compare help us to prosper and evolve beyond the small, self-contained tribal groups of our early ancestors to the free agents connected to 18,000 Facebook friends that we are today. Can you explain how that process of evolution, so to speak, works? Was there one tribe of cave people who saw that another tribe had a cool new tool—a fork or a rake, perhaps?—that made them say to themselves, “We must have that luxury too!”?

A: Look at the space race. In the 1950s and 1960s, the U.S. and U.S.S.R. were simultaneously striving to send a man to the moon. The U.S.S.R. had sent the first man into space and President Kennedy was adamant that the U.S. would be the first country to land a man on the moon. Had both countries approached the task in isolation, without considering the other country’s achievements, the blistering pace at which space technology advanced during those decades might have slowed to a relative crawl. The same is true of rival corporations—Steve Jobs at Apple competing with Bill Gates at Microsoft, for example—where our tendency to compare ourselves to others drives competition and hastens advancement.

Q: That seems to be true when it comes to the creative arts, too: Had Herman Melville not been friends with Nathaniel Hawthorne, or Van Gogh with Gaugin, maybe their output would have been less spectacular.

But another question: How does the comparison instinct play out in today’s world, possibly in a negative way? So much of the information we get about our peers these days is out of context: On social media, people tend to only talk about their successes and happy experiences, so that we may not see the full, um, picture. (We get to see the vacation photos from Turks and Caicos; we don’t see the argument during the dinner party.) Plus, Facebook makes it painfully easy for us to compare ourselves to others all through the day. Does the instinct to compare largely work against us now, in a moment that is so dominated by social sites?

A: I don’t think social media platforms have heightened our tendency to compare—that’s something we were doing long before Facebook, Twitter, Instagram, and Pinterest arrived—though they have made it easier, in large part because they present us with so many clear metrics of comparison. In contrast to trying to measure your happiness, wealth, or success against that of another friend, it’s very easy to see how many Facebook friends you have, how many Twitter followers you have, and to find out plenty about the richness of other people’s lives based on the photos, tweets, and status updates they share online.

We’re presented with a huge menu of opportunities to compare ourselves to other people that weren’t available even ten years ago.

Q: People on every rung of the ladder—no matter how successful or rich—seem to compare themselves to others. I’m sure Ben Affleck is always measuring himself up against Brad Pitt, that the Koch Brothers are envious of Rupert Murdoch. Not too long ago, New York magazine ran a profile of the (relatively!) very successful novelist Claire Messud—who nonetheless seemed disappointed that she wasn’t more successful. A few of my novelist friends thought, “Who does Claire Messud think she is? She thinks she has it tough? Puh-lease!” And yet my response to some of those friends—who have multiple novels under their belts and have published in all sorts of rarefied realms!—was, “You think you have it tough?”

My point is this: Comparing ourselves to others makes us so miserable so much of the time—so why do we still do it? I think we have believe, in perhaps a vague way, that it will help propel us forward, help motivate us. And yet the end goal is, ostensibly, happiness—and we sure aren’t getting happier when we compare ourselves to others. I’m not, anyway. I never seem to notice those lower on the totem pole; only those higher up.

A: There are two forms of social comparison: upward and downward. You’re referring to upward social comparisons, in which people compare themselves to others who are more successful than they are. People do that all the time for many reasons. First, it’s aspirational: by comparing ourselves to superior others, we’re more likely to focus on how they became successful, and to focus our own pursuits on attaining a similar level of success.

It’s difficult to move up the ladder of success if you don’t consider how other people made their way up the ladder before you.

We also compare ourselves to superior others because it’s comforting to believe that we’re playing in the same league—if we are, as in the case of Ben Affleck relative to Brad Pitt. But the same approach would offer little psychological comfort to an actor scraping by with a string of extra credit. Upward social comparisons only do their best work when the aspirational target—the person you’re looking up to—isn’t too far ahead of you.

The other form of social comparison, which you glossed over, is actually very common: the tendency to look down on people who are below us on the ladder of success. People do this all the time because it makes them feel better about themselves, and they do it in every imaginable domain, from wealth to physical attractiveness to success at work. We don’t always make these comparisons explicitly, but we constantly puff ourselves up by focusing on the areas in which we’re doing slightly better than our peers.

Q: In your book, you talk about how being surrounded by trees—or even just having a view of a single tree—can have a dramatic effect on our psyche, much like certain colors can. I was shocked by some of the studies you described—like the one about how much a view of trees can help hospital patients.

A: The extent to which nature can improve our health and wellbeing is striking. People recover more quickly from surgery when their hospital rooms look out on natural views: One study of patients recovering from routine surgery found that those who faced a brick wall needed an extra day to recover before returning home—and that they were also far more depressed and experienced more pain.

Q: I think about that study every day, when I’m trying to decide whether I should go for a run in the park or hit the gym.Nature benefits kids who are going through difficulties too, doesn’t it?

A: Children who experience stressful events are more likely to bounce back if their homes are set among natural settings, too. In one study, those who experienced hardship growing up—because their parents divorced or because they were bullied, for example—were far more resilient when their homes were set amidst natural views, and even when they happened to live in homes with potted plants. In another study, children with ADHD were happier and healthier when they played in natural rather than manmade environments.

Although I wasn’t surprised that the natural world has benefits, I too was surprised by just how profound those benefits can be. In one of the surgical recovery studies, patients needed half as many painkillers during recovery if they looked out onto a small stand of trees rather than a brick wall in the distance.

The basic idea is that natural views restore our mental sharpness and physiological functioning because they stimulate our senses without demanding much from us in return.