Overtly Intentional Communication
Ostensive communication plays an especially pivotal role in the pervasiveness of human culture.
From Biological adaptations for cultural transmission? by Thom Scott-Phillips:
Why is culture so much more pervasive in humans than in other species? On this social minds and epidemiological view, the distinctive, overtly intentional character of human communication plays an especially pivotal role. In overtly intentional communication—sometimes called 'ostensive' communication—communicators actively reveal their informative intentions to their intended audience. This aligns the interests of communicator and audience. Even if they are otherwise in conflict, such as in a heated argument, individuals engaged in overtly intentional communication share the high-level goal of identification of the communicator's informative intention. This opens up, or 'unleashes', the domain of human communication, and hence allows humans to communicate about any available topic, to make salient what would otherwise be opaque, to express abstract ideas, to help others learn and more broadly to facilitate the flow of ideas and practices on a grand scale.
