diff --git a/includes/environment.inc b/includes/environment.inc
index 94bcbca..c93498c 100644
--- a/includes/environment.inc
+++ b/includes/environment.inc
@@ -669,9 +669,9 @@ function _drush_bootstrap_global_options() {
   drush_set_context('DRUSH_VERBOSE',     drush_get_option(array('v', 'verbose', 'd', 'debug'), FALSE));
   drush_set_context('DRUSH_DEBUG', drush_get_option(array('d', 'debug')));
 
-  // Backend implies affirmative
-  drush_set_context('DRUSH_AFFIRMATIVE', drush_get_option(array('y', 'yes', 'b', 'backend'), FALSE));
+  // Backend implies affirmative unless negative is explicitly specified
   drush_set_context('DRUSH_NEGATIVE',    drush_get_option(array('n', 'no'), FALSE));
+  drush_set_context('DRUSH_AFFIRMATIVE', drush_get_option(array('y', 'yes'), FALSE) || (drush_get_context('DRUSH_BACKEND') && !drush_get_context(DRUSH_NEGATIVE)));
   drush_set_context('DRUSH_SIMULATE',    drush_get_option(array('s', 'simulate'), FALSE));
 
   // Suppress colored logging if --nocolor option is explicitly given or if