In the years that followed I obtained a PhD and became a professor in the areas of cognitive science and neuroscience. I learned about perception and behavior, and about the neural circuitry that gives rise to those perceptions and behaviors. I learned about the incredible feats of which our brains are capable. I studied the evolutionary pressures that led to the development and refinement of our neural circuits.

One of the more fascinating things I learned is the way our brain, at the earliest level of processing, categorizes every stimulus that we perceive. This is perhaps the most fundamental capability for any living being: if I see a lion today and barely escape with my life, I want to learn very quickly that all four-legged, furry creatures with long claws and sharp teeth are best avoided.

Survival requires learning. Learning requires categorization. Categorization requires that things that are different be perceived as being the same.

A key observation is that, for most stimuli, perceptual categorization is learned through experience. As a result, the same stimuli will be categorized differently by different people. This is why the Eskimos allegedly have seven different words for “snow,” and why Italians like myself are so picky about what shape of pasta noodle should go with what sauce (spaghetti and meatballs was not invented in Italy).

It is also a known fact that the more we experience a given class of stimuli, the more neurons will be dedicated to processing those stimuli, and the finer our ability to discriminate between two things that may seem identical to less experienced people. Think about a sommelier discriminating between fine wines, or the way an artist can identify the most subtle differences in the shade of a color.

Conversely, when we are only exposed to a small number of exemplars (be they snow flakes, wine bottles, or paintings), it is hard for us to tell them apart, because our brains are wired to categorize based on similarities first, and to focus on differences later.

What does this mean? It means that to a bunch of Japanese kids who have only seen a few black people in their lives, all black people look very similar. Just as to a bunch of black kids who have only seen a few Asians, all Asians look alike.

With this, I do not mean to make excuses for myself, for the Japanese kids, for the black kids, or for anyone else. What I wish to do, is to point out some issues to ponder.

First, perceptual categorization is unavoidable, and the ability to tell the difference between stimuli that are very similar requires a lot of exposure to those stimuli. You simply cannot will yourself to become a wine connoisseur: you have to taste a lot of wines.

Second, there has been a lot of research on cognitive biases and how they impact our behavior. I have not seen nearly as much work on perceptual biases, but I suspect that many undesirable behavioral traits like prejudice, bigotry, xenophobia and racism, have their roots in perceptual biases. Some recent findings suggest that visual biases may in fact be at the root of racial biases.

Third, and most important in my opinion, we all need to realize that these perceptual biases exist, and that it is when they become associated with negative behaviors and social biases that the perceptual biases become harmful.

How do we counter the potential negative impact of perceptual biases? One way is to expose ourselves and our children to more people of more ethnicities more often: look for events in your area that are likely to be frequented by people of different ethnicities; invite people of different ethnicities to your home; make friends with people of different ethnicities at work.

Another way is to make a conscious effort to recognize that these perceptual biases exist, and to learn to recognize them in your daily life: when you see someone who looks different, force yourself to “see them” as an individual person, not as someone representing a category of people based on skin color; when you read an article or a news item, learn to spot the use of categorical labels such as “black,” “white,” “Asian,” “Latino,” “elderly,” “gay,” “poor,” “liberal” or “conservative,” and ask yourself whether the categorization is meaningful, useful, or justified.

A third way is to expose yourself to situations in which you are different: if you live in New York, go visit Harlem, the Bronx, Queens, Chinatown, Korea Town, Little India, Jackson Heights or the Upper East Side (to name a few of the myriad ethnic areas around the city); if you live somewhere else, find out where there are areas frequented by people of different races; and if you truly live in a racially homogeneous geographical area, go travel around your country or around the world.

Finally, try to educate yourself about these issues, and in particular try to learn about the points of view of those who are different from you: read their books, explore their online content, watch their TV shows, rent their movies, listen to their music, eat their food.

Only by understanding and acknowledging our differences can we learn that, fundamentally, we are all the same.

And this kind of learning is the best way to help us overcome the biases some of us did not even know we had.