When we make decisions we think we’re in control, making rational choices, using our logical, analytical left brain, but actually that’s not so. According to a new book, Predictably Irrational by Dan Ariely, we are anything but rational beings. Most decisions are based on highly irrational influences, which are all relative. We estimate the value of things according to how they compare with other things.

Most of what we consume from the world around us comes through our sight. We visually compare one option against another. In the diagram above, the green circle on the right is the same size as the one on the left, but the context is different and influences our perception.

Brands that have a real dedication to the value of visual aesthetics, like Target, Apple and Starbucks, dramatically influence how their brand is perceived. Brand guru, Marty Neumeir says that aesthetics is “the language of feeling, and in a society that’s information-rich and time-poor, people value feeling more than information.”

Aesthetics is so powerful it can turn a commodity into a premium product. How did Starbucks differentiate itself from Dunkin’ Donuts ten years ago? How was it able to change the accepted price of a cup of coffee? Dan Ariely, tells us that a decade later, Starbucks has actually changed our very understanding of coffee and its value, whether you get it from Dunkin’ Donuts, McDonald’s or the grocery store.

The irrational nature of the human psyche may be the best reason yet to influence your brand perception by managing the aesthetics.