The map is not the territory.
This quote from philosopher Alfred Korzybski refers to the idea that an abstraction or reaction about something is not the thing itself. While Korzybski is making a statement about confusing representation and reality, it can be directly related to human perception as well.
Take, for example, color. How does one know that the color they perceive is actually the color they are seeing? Someone who is color deficient doesn't know that. Everyone around them tells them a certain "color" is red — and they may believe that to be so — but the color their brain actually perceives is something closer to green. Is that distorted perception (as the majority of the populace may believe) or is that simply their "truth"? The matter of perception is extremely complicated.
Would it be a stretch to say that every single event in human life affects perception? Even if one small experience does not directly affect my perception, it is a collection of experiences that has an indirect affect.
Taking a look at daily mundane practices, such as a trip to the grocery store, I would imagine it has no direct impact on anything other than my budget or amount of empty space in my refrigerator. However if I have a negative encounter with a cashier, it is highly likely I will avoid that cashier's lane the next time I am at the store because I perceive that he is careless. The reality of the situation could be that he just learned some bad news and was simply distracted. He didn't pack my eggs in the grocery bag upside-down intentionally but my perception of his ability as a cashier is altered.
We do not see things as they are, we see them as we are.
Anais Nin wrote this beautiful, slightly stinging, but very true statement that raises a bigger question in my mind; do these differences in perception matter? Or are those nuances in perception what make us human?
I wonder, were there no differences in perception, would there be need for design research?