How People See – Scanning Based on Past Experience and Expectations, and Selective Disregard & Change Blindness (Part 3)

Our vision trumps all our other senses. Half of the brain’s resources are dedicated to seeing and interpreting what we see. What our eyes physically perceive is only one part of the story. The images coming in to our brains are changed and interpreted. It’s really our brains that are “seeing.”

You think that as you’re walking around looking at the world, your eyes are sending information to your brain, which processes it and gives you a realistic experience of “what’s out there.” But the truth is that what your brain comes up with isn’t exactly what your eyes are seeing. Your brain is constantly interpreting everything you see.

In our third part of this article, we discuss about Scanning Based on Past Experience and Expectations, and Selective Disregard & Change Blindness.

Scanning Based on Past Experience and Expectations

People tend to scan objects based on past experience and expectations. For designing websites, it is important to know where online users will look first and to know where they will look afterwards.

How people look at objects will determine where to place our web elements. All this depends partially on what they’re doing and expecting. If they read in a language that moves from left to right, then they tend to look at the screen from left to right. If they read from right to left, it is the opposite. However, they don’t start in the topmost corner. Because people have gotten used to the idea that there are things on computer screens that are less relevant to the task at hand, such as logos, blank space, and navigation bars, they tend to look at the center of the screen and avoid the edges.


People have a mental model of where things tend to be on computer screens, and a mental model for particular applications or Web sites that they use. They tend to look at a screen based on these mental models. For example, if they are looking for information, they’ll likely look right at the search field when the screen loads. If there is an error or unexpected problem with the task people are trying to accomplish, then they stop looking at other parts of the screen and narrow their view to focus on the problem area.


Selective Disregard & Change Blindness

Our brain does a surprisingly good job of tricking us into thinking we absorb everything we see, but we often miss things that happen right in front of us. This phenomenon is called Selective Disregard and it happens out of the necessity as it’s impractical (and arguably impossible) to process every visual peripheral vision.

Just walking down the street, you are exposed to millions of visuals that could demand your attention. But unless they are necessary, your mind filters them out as if you never saw them. The most obvious example of selective disregard is banner blindness, where users have become so accustomed to ignoring online advertising they couldn’t tell if the website they surfed five minutes prior had as or not.

Selective disregard applies to more than just advertising. Users often gloss over anything that doesn’t appear to their task at hand. For usability, all element should be clearly labelled and follow conventions matching the user expectations. The more extreme brand of selective disregard is change blindness.

Change blindness occurs when the state causes blindness of large and obvious changes. Our mind does all it can to conserve energy. One way it conserves energy is assuming nothing has changed unless there is a clear indicator otherwise. So if something changes on your page, you better make it obvious. Small loading GIFs and flashing content might not be enough. When in doubt, make changes painfully obvious.


The “How People See” is a 4-part article. The next part will discuss more on The Meaning of Colors. Visit us again for the next part.

You can also read our previous parts here:

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