Is the rise of hedging language in scientific papers correlated in time with the rise in peer review?
In a talk at FORCE2016 (https://www.force11.org/meetings/force2016), Steven Pinker discussed bad writing in science, and mentioned how it had changed over time. One of his statements was that scientists hedge (for example, using hedge words such as "generally" rather than making stronger points; see http://www.uefap.com/writing/feature/hedge.htm) more than they used to. Some of this may just be style, due to the changing preference and practice of the scientific community, but it also would be interesting to see if this change is related to the rise of peer review (which has become standard relatively recently; see, for example, http://theconversation.com/hate-the-peer-review-process-einstein-did-too-27405). Perhaps authors now try to be less definitive to avoid giving reviewers grounds to reject their work.
This hypothesis could be examined by measuring the use of hedging language (for example, through natural language processing) in articles in a particular domain (physics, for example) and seeing if it is correlated in time with the rise in peer review (which could be obtained through research into the history of science writing, or which may have already been collected.) If this were true for multiple domains where peer review became standard at different times, it would be a strong argument for the hypothesis to be true. This also could be done for specific journals, rather than domains.