XP from dialogue?

[Extreme Content]

I just started this game and I went through the opening bit once with John Shepard and then I made my own character. The first time I investigated in my talks with the navigator and the doctor, then chose neutral responses to the other dialogue. I got XP. The second time around I got Paragon points for choose good responses but I didn't investigate anything. I got no XP. So... you get XP for investigating, I take it?

[Xavier]

If you choose dialog options that open some backstories (IE Codex entries), then you get XP. Also, some dialog options are absolutely necessary to get the Historian Acheivement.

[StaTiC haVoc]

Yea if it opens new stuff in your codex, you will get some xp, very little though. Some options also will get you a few paragon/rengade points.

[Xavier]

Once you get the hang of the types of dialog options on the wheel, you can steer a conversation pretty quickly. Dialog options on the right side of the wheel generally lead to the close of dialog. Left side options keep it running, if possible. Top right choice is positive, middle is neutral, bottom right is negative, top left is charm, middle is neutral again and bottom left is intimidate.

[Extreme Content]

Thanks for the help.