What Designers Should Know About Visual Perception and Memory

15 Mar

Closeup of an eye

A very interseting post on a blog by Steven Bradley on Monday, March 7th, 2011 at:


Here are some excerpts:

When a visitor lands on your web page and begins to look around you hope your message is communicated clearly and understood. On the surface this may seem like a simple one way transmission of ideas from your design to the viewer’s eye. The reality is more complex.

Visual perception is the result of complex interactions between external visual stimulus and prior knowledge, goals, and expectations. Understanding how we all perceive things visually will help designers communicate better.

This post will focus on the theory and science of visual perception and memory. Much of the information comes from the book Visual Language for Designers by Connie Malamed, which I recently read and recommend.

Visual Processing

Perception is the process of obtaining awareness and understanding of sensory data. We take in something visually and then need to process what we see in order to derive some meaning from it.

Our brains need to find meaningful patterns in our visual environment in order to make decisions about what to do and how to respond.

Human beings process sensory data in parallel as we interact with the world. Different regions of the brain are simultaneously activated through networks of neurons. This parallel processing allows visual perception to be both fast and efficient and it’s why designs can communicate quickly and efficiently as well.

Visual perception is a two way street. We see small details in the environment and take them all in to see the whole. We also bring to our environment knowledge and specific goals that determine where we look and influence our interpretation of sensory data.

How we perceive things is a combination of both bottom-up and top-down processes.

Schematic of the eye

Bottom-Up Processing

The bottom-up process is driven by external stimuli.

The human fovea can only focus on a very small area at one time and we see through a series of saccadic movements of the eye.

We fixate on one location for a moment and then move on to the next fixation. We take in little at each fixation and it’s through a pattern of saccades that we take in our visual environment.

This all occurs quickly and early in the visual process without any conscious effort or attention on out parts. It happens so quickly we’re not even aware it’s happening.

At a glance we detect the following without conscious awareness.

Each therefore can be used to attract attention to something in your design. As we process the above information our brains

This all occurs rapidly helping us to recognize and identify objects on the page. This information is quickly passed to other areas of the brain and influences where we place our attention next.

'Everything is a matter of perception' standing out as red words in a sea of white letters

Top-Down Processing

The top-down process is driven by prior knowledge and expectations as well as our specific goals of the moment. What we know shapes our interpretation of the things we see. The task at hand influences where we look next.

We tend to disregard anything that isn’t meaningful or useful at the moment. In the image above the red letters spelling out “Everything is a matter of perception” clearly stand out due to the contrast in color.

Your mind is looking for words in a sea of letters as we generally expect a pattern of letters to form words and sentences, etc.

Most of the other letters fade into the background as you read the sentence in red.

Suppose though, I asked you to find all the occurrences of the letter “P” in the image? Now as you scan the image the letter “P” should start to stand out a bit more and it’s possible that even the highly visible red letters start to fade into the background. At the very least you likely aren’t noticing the words they spell out.

The task at hand is affecting your visual perception. You see more of what you’re looking for and less of what you aren’t. This top-down process so affects our visual perception that some suggest we see more with our mind than with out eyes.

What we know, what we expect, and what we want to do influence what we see.

Abstract illustration representing free of thought


We hold information in different kinds of memory. Sensory memory records fleeting impressions that last a few hundred milliseconds. This is long enough to hold the prominent features of what we see long enough to further process them.

When sensory information is auditory we call this echoic memory and when the information is visual we call it iconic memory.

Please read in full and write a comment about how this migt affect your work/blog.


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