“That’s not fair!” said George, my oldest. He was 4 then, and the injustice prompting his outcry was the arrival of two small cups of orange juice at the breakfast table, one for him and one for his younger brother, Henry. The problem was not that Henry’s cup contained more juice — God forbid I should make that mistake twice. I had mastered the art of doling out their servings with utmost precision, crouching eye level as I filled their cups. No, this morning’s crime was that I had set Henry’s on the table a moment before George’s.

Cucumber-Grape Gazpacho

His outburst made me laugh. Then, as the morning wore on, it made me puzzled — at the sheer impossibility of trying to parent fairly. When something as scientifically quantifiable as volume doesn’t cut it, what can a parent do?

The answer, of course, was to shift my own approach to fairness — away from a principle of how I should treat my kids (where fair=equal=interchangeable), toward an effort to be equally present with each of them, however they wanted and needed. It meant switching my brain onto a more curious and open-minded track — from a top-down attitude to an outside-in one.

In the 20 years since then, fairness never stopped mattering in our family, although the ways it mattered changed radically as we grew.

It turns out that fairness is written into our deepest animal instincts. Twenty years ago, Frans de Waal and Sarah Brosnan published a study in Science, one of the world’s leading academic journals. In their lab, capuchin monkeys were rewarded with pieces of cucumber for handing a researcher a pebble. Capuchins love fresh vegetables, so they delighted in the exchange.

Then the researchers began rewarding one monkey with a grape, while her neighbor still got the cucumber. Suddenly, the second monkey didn’t want her reward, and would even sometimes throw it back at the researcher. And when some monkeys were offered grapes for doing nothing at all, tantrums ensued.

Economists cite this study when discussing questions of fair pay. To them, it demonstrates that disparate pay leads to dissatisfaction and conflict in the workplace. To sociologists and evolutionary biologists, meanwhile, the study reveals that human beings did not invent notions of fairness and justice.

To me, it also points out the power of fairness to color even simple, day-to-day experiences. The flavor of the cucumber didn’t change from the first part of the experiment to the second, but how good it tasted changed dramatically.

One morning not long ago, I appeared to be meditating in my study. Suddenly, my brain came online and began to chide me for treating whole swaths of my life like those cucumbers. Days went by, even weeks, when I was submerged in nothing but cucumbers.

Do we all do this? If our body isn’t perfect, do we love it or resent it? If our career, marriage, house, garden, car or lucky breaks aren’t as grapey as someone else’s, do we walk around filled with appreciation or discontent? Try as I might to count my blessings, I had to admit that my perception often resembled that of a pissed-off capuchin. And even when I don’t measure my gifts against another person’s, I have a tendency to compare my life to how I thought it was “supposed to” turn out.

Oh sigh, I thought as I sat there with my eyes closed, impersonating a meditator. Maybe it’s time I learned how to love cucumbers again, as well as grapes. And while I’m at it, what if I tried loving them together? Like, in a cold soup! I stretched my legs, headed into the kitchen and whipped up this gazpacho. I’ve kept a jar of it in the refrigerator on and off ever since. It happily welcomes all kinds of vegetables, even — especially — cucumbers.

And George and Henry love it when I place cups of this soup in front of them, even if I don’t set them down simultaneously.

Cucumber-Grape Gazpacho

Note: You can substitute any green, leafy vegetable for the spinach (I’ve used beet greens, chard and baby kale). And you can substitute full-size cucumbers for the minis; simply peel and de-seed them before using. You can also vary the quantities of all the ingredients to suit your preferences and palate.

Put all the ingredients except the ice cubes in a blender and pulverize until smooth. Add half the ice and puree again. Taste for flavor, adding more vinegar, salt and pepper as needed. Serve with an ice cube and a drizzle of olive oil, if desired.