Okay, fine. But is there a visual knowledge?
This paper says yes, and suggests we're missing a lot with our traditional measures of what people know.
The less educated, for example, do better on tests of visual political knowledge. What's that mean, visual? We can test this by randomly assigning some folks to a verbal only question, some to a visual only, and some to a mix. So in the verbal only, you'd get a question asking what office does John Kerry hold. In the visual only, you'd be asked to identify his office from a photograph. And the third group would get words and a pic. All would have identical multiple choices, four of them, with one having the correct answer of U.S. Secretary of State.
In summary, Marcus Prior notes:
Visual political knowledge is different from verbal political knowledge and represents a previously unmeasured element of political involvement. This study has shown that adding visuals to otherwise identical all verbal knowledge questions significantly increases correct responses. This finding strongly suggests that some people with substantive knowledge of political figures respond incorrectly to knowledge questions about them just because they lack a phonological representation of the person (the politician’s name). Allowed to draw on a visual representation (the politician’s face), they are able to report accurate conceptual knowledge about the politician.
So there are "visual people" out there, especially when it comes to how we measure political knowledge. I'd argue that the more you rely on TV for news, the more "visual" you are and the better you'd do on tests like this.