diff --git a/lib/assignable_values/active_record/restriction/scalar_attribute.rb b/lib/assignable_values/active_record/restriction/scalar_attribute.rb
index 6ec40af..75fd1b1 100644
--- a/lib/assignable_values/active_record/restriction/scalar_attribute.rb
+++ b/lib/assignable_values/active_record/restriction/scalar_attribute.rb
@@ -88,7 +88,7 @@ def define_humanized_assignable_values_instance_method
 
             unless multiple
               define_method :"humanized_#{restriction.property.to_s.pluralize}" do
-                ActiveSupport::Deprecation.warn("humanized_<value>s is deprecated, use humanized_assignable_<value>s instead", caller)
+                ActiveSupport::Deprecation.new.warn("humanized_<value>s is deprecated, use humanized_assignable_<value>s instead", caller)
                 restriction.humanized_assignable_values(self)
               end
             end
diff --git a/spec/assignable_values/active_record_spec.rb b/spec/assignable_values/active_record_spec.rb
index 5d8dc98..953c9b6 100644
--- a/spec/assignable_values/active_record_spec.rb
+++ b/spec/assignable_values/active_record_spec.rb
@@ -1277,7 +1277,7 @@ def genres
                 %w[pop rock]
               end
             end
-            ActiveSupport::Deprecation.should_receive(:warn)
+            expect_any_instance_of(ActiveSupport::Deprecation).to receive(:warn)
             genres = klass.new.humanized_genres
             genres.collect(&:humanized).should == ['Pop music', 'Rock music']
           end