wp_list_pages configure problems

I want to list my pages without the pages title, like so:
wp_list_pages(‘title_li’)

but I also only want to go to a depth of 1, i.e. only show the first parent pages, not child pages.

I have tried
wp_list_pages(‘title_li=’,’depth=1′)

and
wp_list_pages(‘title_li=,depth=1’)
and
wp_list_pages(‘depth=1,title_li=’)

this doesnt seem to work, any idea how to fix this?