[mattkrause]

This implicitly "punishes" subfields that move more slowly. It can take over a year to train a monkey to perform complicated behavioral tasks. In the same time period, you could breed 50+ generations of fruit flies, or ~25,000 generations of bacteria. Furthermore, the monkey researcher will have fairly little interim data, whereas the bacteria or fruit fly work may have something interesting within a few weeks.

This could be normalized within fields, but in practice it's not. For example, the NIH K-awards have a fixed eligibility period, which seems to keep shrinking.