How do I display information about a node's author on the full node and not the teaser view?
Just pop an if ($page): condition around it:

&lt;?php if ($page): ?&gt;

  &lt;?php if ($display_submitted): ?&gt;
    &lt;?php print $user_picture; ?&gt;&lt;?php print $name; ?&gt;
  &lt;?php endif; ?&gt;

&lt;?php endif;?&gt;


In the context of node.tpl.php $page is defined on the docs page as a:


  Flag for the full page state.