Well both, but I suspect that just as the need to be published in high impact journals is growing for PhDs and Post-docs, the need to be published with new discoveries is also growing. I think in biology (and particularly in pharma), competition for good thinkers is increasing. I think it is not uncommon to consider 8 or 10 candidates seriously for a position at that level. Maybe it would just put more pressure on the scientist to publish in a post-doc position.