Displaying only excerpts on index page

I upgraded to 2.1 and at the same time am trying to build a new site (my 4th WP site) that uses excerpts on the index page. I saw the post here: https://www.ads-software.com/support/topic/36593?replies=3#post-206972

but that doesn’t seem to work for 2.1; both the excerpt and the full content of the post both display, in order, for each entry.

Because I haven’t tried to use this feature prior to now, I can’t say for certain that it’s a 2.1 problem, but signs seem to be pointing that way.

There aren’t any radio button settings I may be forgetting, are there?

If not, any help someone might be able to provide would be much appreciated.