Real estate with ocean views, stunning mountain vistas, and wide-open green spaces sell at premium prices because humans find those settings pleasing [1-5]. Certain color combinations in fashion—such as brown and forest green—blend harmoniously, while others, such as hot pink and orange, clash. And our eyes like certain proportions in visual objects (like buildings and human faces) but not others.

These “facts” of visual aesthetics are so well established and obvious that we don’t stop to question them. But here we will, asking, “Exactly why is it that our eyes like what they like?”

The biology of aesthetics: The obvious

As with other dimensions of everyday experience, what we find aesthetically pleasing is not random but stems from our evolutionary history. Just as our innate preference for sweet, calorie-rich food helped our ancestors survive in environments where food was scarce, our preferences for certain visual stimuli reflect the survival imperatives that confronted our ancestors.

Let’s start with an easy one: toxic substances, such as those in rotting meat, tainted water, or feces. Although our noses are the primary defenders against such threats, our eyes also play a role. Rotting meat, moldy bread, and dirty water usually have a distinct, “ugly” look. According to ecological valence theory [6, 7], we generally prefer colors, such as green, that are associated with non-toxic substances and dislike those, such as brown, that are associated with objectionable substances. Similarly, color combinations that occur in welcoming environments—such as sky blue and light brown tree bark in forests—”match,” whereas color combinations that do not occur naturally “clash.” The color pair below on the left, coral and turquoise, evokes the southwestern desert, while on the right, hot pink/neon green evokes eyestrain.

Our preferences for faces and body proportions also arise from the evolutionary imperative to find a healthy mate with which to reproduce. Evolutionary psychologists [8-10] theorize that symmetric faces and well-proportioned bodies (following the model of Da Vinci’s Vitruvian Man, left) signify good nutrition and lack of disease during childhood, increasing the reproductive fitness of a potential mate.

Less obvious origins of visual preferences

It makes sense that visual signals of toxins should repel us and that signs of health should attract us, but why do we like ocean views, sweeping vistas of mountains and forests?

From a survival standpoint, oceans are an abundant source of food and are often fed by rivers of fresh water. Bodies of water also offer unrestricted sightlines, preventing nasty surprises, according to the “Refuge theory” of environmental preference [1]. The Savanah [2] and Park [3] theories of environmental preference echo the advantages of wide-open spaces for predator avoidance on the one hand, and for visibility of food on the other, especially when such spaces are rich in green vegetation, signifying abundant food and water. [5]

Consider the two cityscapes below:

The left image is a typical urban scene with little vegetation, whereas the right image depicts a more “natural” setting with an open sky, lush vegetation, and blue water. According to the principle of biophilia (attraction to nature) [5], most of us would choose to live and work in the city on the right.

But there’s more to the appeal of the urban setting on the right than vegetation and open sky. The cityscape on the left is cluttered and cacophonous, while the one on the right is open and harmonious, with scenic elements and color combinations found in nature. The scene on the left is jarring, while the one on the left more “restful.” The term “restful” is not random here, because it correlates with a much lower cognitive workload, in which we needn’t spend time and energy sifting out what’s important from what isn’t.[11] Cognitive psychologists describe the ease of processing information in a scene as “perceptual fluency,” where we tend to prefer simpler scenes that afford high fluency over complex ones with low fluency.[12]

Considering the options below, most people would prefer not to live in the space on the far right, preferring an environment that did not wear out our brain with cognitive/sensory overload.[12]

But research on visual complexity [11] reveals that our preferences for visual complexity are, well, more complex than the simple “less-is-more” approach. Too little complexity (above, left) is actually less preferable to most people than “optimum complexity” depicted in the middle room image. [11]

Similarly, the majority of viewers would find the scene on the right, below, more inviting than the scene on the left, because it is less boring. Evolutionary psychologists would also observe that the scattered trees offer shade and protection from predators.[2]

Conclusion

A major caveat is that beauty is in the eye of the beholder, so that there is no such thing as universal visual preference, just approximate rules of thumb.

If you’re wondering why the origins of visual preferences are worth discussing in the first place, my answer is: They aren’t—unless you care about trivial things such as where you live, the value of your house, what you wear, or with whom you mate.

Humans are, above all, visual animals: animals that evolved in primordial environments that shape who we are today.