Multi-authors view own posts only on dashboard

I manage a multi-author website on WordPress 2.8.4 with the Atahualpa theme. I’m looking for a way to limit each author’s view of posts in the edit post screen to only their own posts. Each of the 80 authors can now see everyone’s post in the edit post screen of the dashboard, though they can only edit their own posts.

I use the role manager plugin but don’t see any options for authors viewing only their own posts.