Grammar, Usage / Can I use "I" rather than "The author"? [6]

I am quite perplexed to hear some of the senior lecturers from where I am studying told me how, as a researcher, I shouldn't use the first person "I" and use instead, "The author" or The researcher". I believe it shouldn't be the case, and am wondering if you guys here might say otherwise.

Can someone here pinpoint me a precedent studies or guideline in the net that shows that I can use "I" in my thesis?

Thank you very much.

(By the by, I am doing Semiotics research in comics and films. Still in my Master degree.)