but the mode of visual narrative used was...

does the highlighted sentence mean:

1. "its members tended to gravitate toward certain forms, which visual narrative was only one of those possible forms"

or

2. although its members tended to gravitate toward certain forms, they could choose the mode of visual narrative that was used, among a number of possibilities"

context:

With the slow advance of literacy through the classical world, a variety of more complex strategies for telling stories were devised. Though the examples here follow more or less a chronological order, there is no evolutionary pattern to these various forms of early narrative art. Once a society developed a certain degree of literacy, its members tended to gravitate toward certain forms; but the mode of visual narrative used was a choice among a range of possibilities.