What aspect of New Orleans jazz primarily influenced later jazz styles?

The influence of collective improvisation in New Orleans jazz on later jazz styles is significant. In this early form of jazz, musicians would often play together in a spontaneous manner, creating complex musical dialogues. Rather than performing in silos, they contributed individually to a shared musical experience, which enhanced the unity and richness of the sound. This practice laid the groundwork for many future jazz genres that embraced improvisation as a core component, such as bebop, cool jazz, and free jazz.

New Orleans jazz's focus on collective improvisation allowed for a unique blend of voices and instruments to interact in real time, fostering creativity and spontaneity. As jazz evolved, this emphasis on collaborative musical expression became a hallmark of the genre, influencing musicians' approaches to composition and performance.

The other options highlight elements of jazz that, while important, do not encapsulate the defining characteristic that has had such a lasting impact on subsequent jazz styles. For instance, strict adherence to written scores would tend to limit improvisation, while a sole focus on vocal performances and the use of microtones are more specific to certain styles or traditions rather than the broad influence of New Orleans jazz.