diff --git a/lib/graphiti/adapters/active_record.rb b/lib/graphiti/adapters/active_record.rb
index 00d2c8e4..7598b6b2 100644
--- a/lib/graphiti/adapters/active_record.rb
+++ b/lib/graphiti/adapters/active_record.rb
@@ -250,7 +250,7 @@ def associate_all(parent, children, association_name, association_type)
               parent.send(association_name) << child
             else
               target = association.instance_variable_get(:@target)
-              target |= [child]
+              target = [child] | target
               association.instance_variable_set(:@target, target)
             end
           end