Your project intrigues me, but without further details, I am not sure how to tailor my proposal. You state that there are two tasks, but do not elucidate on them. All that is clear is that you need someone with a strong command of the English language, knows how to write "scientific papers" (I take this to mean academic/peer reviewed journal articles), and has some familiarity with psychology. I may or may not be the person you need.
I have a PhD in communications, so I am familiar with writing academic papers (though not necessarily in the "science" fields as I am more of a "social scientist"). I believe I have a strong command of the English language in terms of writing, grammar, etc. If you need help with researching, providing summaries, annotated bibliographies, proofreading, etc. I might be the person for you. But if you are looking for someone to write a formal 20-35 page psychology article for you, I am not the one.
Please message me if you think our goals may align and I may be of some use. I would be happy to edit my bid/proposal to better suit your objectives once I understand your needs better.
Thank you for your consideration,
Courtney