Do publications outside your primary field of study help or hinder your early career? I'm an interdisciplinary PhD student and I've heard conflicting reports on your publication record in your early career. Some members of my host department say that you should stay focused while others outside the department say it can help. Given that my dissertation is by publication and I've got one core field and two secondary, what would a hiring committee expect my CV to look like? Would publications in tertiary field (as primary author) be looked upon negatively?
If you have 5 publications in 5 different areas, I would be concerned that you might become the eternal prodigy or that you are not willing to perform some long term research. However, if you have a clear focus and can document that you are working continuously on one project, then activities outside your core area indicate that you are able to work together with very different people. So you won't be hired because you have many publications, if there is no area where you are really convincing. But among applicants, which are similar in the area the position is aiming at, other activities become a significant advantage.