Our mind doesn't like to (or can't) pay attention to the details easily, you have to force it to get focused. This is why we can read words have a typo, especially those had correct start and end, we may even don't understand they have spelling errors. Do you think that the brain is that fast when you pass the streets it scans any people, cars, and ... finds out the shape of them. I don't think so, it has a history of how a human or car looks like, and just by discovering some signs assumes that this is a car and that is a pedestrian. Just think about this example, when you seat in a car, looking out the window how fast you brain should be to process all the things you see in detail?
We human were viewer very long before we get reader
This is not just a journalism title, there is truth in it. Look at the following part of the timeline from the "Timeline of evolutionary history of life" page of the Wikipedia, it is interesting:
- Simple cells: 3.6 billion years ago
- Complex cells: 2.0 billion years ago
- Simple animals: 600 million years ago
- Fish & Proto-Amphibians: 500 million years ago
- Land plants: 475 million years ago
- Reptiles: 300 million years ago
- Mammals: 200 million years ago
- Birds: 150 million years ago
- Great Apes: 20 million years ago
- Homo: 2.5 million years ago (modern human)
- Anatomically Modern Human: 200,000 years ago
From the time fishes or any other creatures used to live in oceans developed eyes to get better use of sunlight, animals started to see things. So this must not be strange why we have a saying:
"Are pictures worth a thousand words?"
Picture gets our attention faster
Pictures instantly get our attention, because our mind is so faster in recognizing shapes than reading words and looking up for their meaning and the give a whole meaning to all. Looking at a glance to a road sign while driving, like the school zone is enough for us to understand than reading a text. Looking at the trend of incomes vs outcomes easily shows us what is going on in the company ...
Reading texts to describe things sometimes is impossible
Consider you want to describe how to change a part in a device. For example a hard disk in iMac (I've done it before) or replacing the injection pump in a car engine. Looking at a couple of pictures is faster, easier and more understandable than reading pages of text to know how to do these replacements.
Remembering is faster when it is visual
We can recall memories, events, things, and ... much faster if we have them correlated to a picture or scene. We even learn things when learning visually, as an English learner, I never forget a word if I see someone uses it in the real world.
Left & Right parts of the brain
Everybody knows this when you use pictures to help better understanding as well as texts, the left side of the brain which is responsible for paying attention to details helps to read and the right side of the brains pays attention to visualization stuff you provided. This is the way you increase your brain usage efficiency.
You can bring so many reasons why a graphical presentation can be more useful than text presentation especially when texts are too long and the reader doesn't have time or power to read and digest all of them (this is why nowadays everybody looks for data-visualization of big data) but if you use both text and picture you'll give better understanding material to your customers.
What I mean is that reading is like bottom up or detail to the whole process, while looking a picture is a top-down process, at a glance you get much information but not that detail reading can get. So using both together can surely reduce the problems we talked about ambiguity in language.