mushaboom

I just did a lab where we tested the relative reactivities of hydrogens by radical brominating ethyl benzene, toluene, methyl cyclohexane, cyclohexane, and t-butyl benzene. One set of reactions was done under bright light and the other was done under our weak fume hood light. In my report, I'm supposed to talk about how only some of the reactions needed light while others didn't. This is tough because all of the reactions took place in light, and all of them reacted at least to some extent. I assume that toluene and ethyl benzene are the ones that didn't need light, but I can't explain why. I looked this up online and read that aromatic compounds can only be substituted in the presence of an aluminum or iron catalyst, which we did not use. Are there other ways as to why the reactions occurred the way they did?