Suddenly I thought of a short story or perhaps feature film idea where the protagonist’s brain is wired so that whenever he sees someone, their clothing, hairstyle, jewelry, all magically revert back several generations to their original ‘ethnicity’.
In this case the Indian man would have on skins, possibly war paint. The girl of what appeared to be Spanish descent walking by us with the ass-enhancing pantware would instead have on some kind off Medieval gown. My wife (of Swiss, German descent), would be sporting an Oktoberfest maiden’s beer serving apparel and Teutonic braids. That sort of thing.
Of course even as I was visualizing all of this I realized that (a) trying to apply any kind of reductionism to one’s ethnic lineage seemed dubious and deluded and borderline dangerous, (b) presenting people this way was far less interesting and life-affirming than seeing their ‘real’ reality right at present time, ground level, (c) part of this idea occurred surely because I have a tendency to reduce people this way myself, say 14% of the time–not appearance-wise, but more a form of cultural / behavioral stereotyping, and (d) the beleaguered protagonist could be played by Ashton Kutcher in a ‘breakout’ production which somehow involved Twitter, Larry King, and the first ever “real-time major motion picture experience with live social media back chat.”
Actually I just invented that last one. By the third or fourth step past the Mapuche man I’d already given up on the idea.
Instead of contriving a story arc wherein Kutcher’s character learns to ‘see people for themselves’ (the payoff of which would surely hinge on a make-out scene with someone ambiguously ‘ethnic’ (but definitely hot)), I began to think about ways of seeing people that can sabotage your writing. Here’s what I have so far:
1. Romanticizing someone else’s life (Ex.: A mountain guide in Ecuador.)
2. Appropriating someone else’s problems / struggle as your own. (Local people being displaced by newer, wealthier immigrants or tourism.)
3. Believing that someone is a “father / mother / brother / sister figure”
4. Making assumptions based on cultural heritage.
5. Isolating people from time / place / family relationships so that they become, essentially, symbols or simply props for the narrator or author’s ego.
6. Attributing the emotions someone made you feel (especially if you’re observing them from a distance instead of interacting) back to them. (Ex. “The carefree Cuban woman.”)
7. Dismissing material / economic connections between yourself and others (The “incredibly affable taxi drivers,” in Costa Rica.)
8. Seeing people exclusively through the filter of strictly-held philosophical, religious, or artistic beliefs / aesthetics.
For travel writers moving quickly through a place, it’s easy to fall into the trap of writing quick notes or impressions, which by default tend to reduce people to symbols or caricatures.
More difficult, more time consuming, is digging for the people’s voices and stories over time and finding common ground in spite of cultural differences, language, and geography.
Finally, how to ‘overcome’ problematic ways of seeing people? The first step is obviously recognizing when you’re doing it. Just being self aware–knowing that you have certain ways you look at things and being as transparent about it all as you can–goes a long way. 
*The travel writing course from MatadorU gives you access to freelance leads for paid travel writing, travel jobs, and press trips, as well as connections to travel editors at Matador and beyond.