Spartan 085

Best answer as chosen by Asker / Ratings
For the Hungerer of Knowledge achievement, you have to find 85% of the memory glitches in the game. During memories, you see actual cracks in the screen and if you press a button while it's on screen, you'll actually see additional scenes in the memory. I'm not sure how many there are but it's basically Ubisoft's way of making you watch the scenes.

For the Conversationalist achievement, you have to talk to Lucy at every opportunity. Just keep talking to her until she tries to end the conversation herself. Once again, I'm not sure how many different dialogs there are but if you do it every time you see her, you'll get the achievement.