diff --git a/AUTHORS b/AUTHORS
index 7788139e..780c9e6c 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -16,6 +16,7 @@ Dervived from the git logs, inevitably incomplete but all of whom and others
 have submitted patches, reported bugs and generally helped make MongoEngine
 that much better:
 
+ * Kelvin Hammond (https://github.com/kelvinhammond)
  * Harry Marr
  * Ross Lawley
  * blackbrrr
@@ -169,4 +170,4 @@ that much better:
  * Massimo Santini (https://github.com/mapio)
  * Nigel McNie (https://github.com/nigelmcnie)
  * ygbourhis (https://github.com/ygbourhis)
- * Bob Dickinson (https://github.com/BobDickinson)
\ No newline at end of file
+ * Bob Dickinson (https://github.com/BobDickinson)
diff --git a/mongoengine/queryset/queryset.py b/mongoengine/queryset/queryset.py
index d58a13b7..e2ff43f7 100644
--- a/mongoengine/queryset/queryset.py
+++ b/mongoengine/queryset/queryset.py
@@ -1062,7 +1062,7 @@ class QuerySet(object):
         """
         map_func = Code("""
             function() {
-                emit(1, this[field] || 0);
+                emit(1, eval("this." + field) || 0);
             }
         """, scope={'field': field})
 
@@ -1093,7 +1093,7 @@ class QuerySet(object):
         map_func = Code("""
             function() {
                 if (this.hasOwnProperty(field))
-                    emit(1, {t: this[field] || 0, c: 1});
+                    emit(1, {t: eval("this." + field) || 0, c: 1});
             }
         """, scope={'field': field})