My understanding is that “psychologizing” is a much more broad than an ad hominem argument. Instead of a simple insult, it is an attempt to dive into someone’s psychology (usually in an adversarial context) and make wild and speculative comments about someone’s state of mind -- rather than address specific content of behavior. At least that's how I understand it. It's very inappropriate, in my opinion, to make broad generalizations about someone's character prior to having adequate information.
Here is a text-book case of psychologizing from another thread in this forum that was directly at me by Reginald Firehammer:
Reginald says: “Don's post reveals a certain kind of personality--the kind of personality that is both easily offended itself and believes the solution is to offend others. That brow-beating method probably works with the kind of people Don is used to dealing with. My response to Don was to demonstrate, it does not work with everyone, that there are people in this world whose relationships with others are based on reason, not emotional manipulation.” [Reginald Firehammer, May 18, 2004, Post 26 of the “Problem of Interaction” thread in the Objectivism Q&A Forum.]
Of course, you would have to go do the “Problem of Interaction” thread to see the full context of his comments… You can read Reginald’s comments (notably: Post 14, Post 24 and Post 25) and decide for yourself. My only comment was Post 23.
In any case, regardless of whether 1) he is was rude to me or 2) I was somehow inappropriately angry at him -- the FOCUS here is on his psychologizing of me. I point out to those who are reading that I have NEVER met Reginald Firehammer in my life. I have no idea who this guy is… I just barely arrived here. Yet how does he portend to know so much about me?
- Notice how Reginald seems to know “the kind of people I am used to dealing with!” How does he know how I am “used to” dealing with others!? From only one post?! Wow.
- Notice how Reginald very directly implies I rely on “emotional manipulation” when I deal with others. Wow, I didn’t even know that about myself. From only one post he knows me well enough to say this?! To the contrary, I thought I was very direct! Where am I “manipulating” him?
You can further break down a wide range of his comments further...but, I'm sure you get the drift.
He bases these deep insights into my psychology from only one post (Post 23)!
This is an important topic because it's very disconcerting when somebody makes such baseless personal attacks at you [although, of course, on the Internet nobody really knows your real name anyhow].
The goal of intellectual discussion, in my view, is to share ideas. It's pretty obvious that psychologizing does not facilitate this process. Good topic for discussion...
I'm sure Reginald will be able to help you out from here.