Index: list.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/modules/list/list.module,v
retrieving revision 1.35
diff -u -r1.35 list.module
--- list.module	11 Oct 2010 19:57:00 -0000	1.35
+++ list.module	14 Oct 2010 17:41:03 -0000
@@ -242,7 +242,7 @@
     }
     // Otherwise see if we need to use the value as the key. The "list" type
     // will automatically convert non-keyed lines to integers.
-    elseif (!$position_keys) {
+    elseif ($position_keys) {
       $key = $value;
     }
     $values[$key] = (isset($value) && $value !== '') ? $value : $key;