use_update option for inherit_attributes.

lib/acts_as_inheritable.rb

@@ -73,13 +73,17 @@ def verify_parent_name(new_relation, model_parent)
         parent_name
       end
 
-      def inherit_attributes(force = false, not_force_for = [])
+      def inherit_attributes(force = false, not_force_for = [], use_update = false)
         if has_parent? && self.class.inheritable_configuration[:attributes]
           # Attributes
           self.class.inheritable_configuration[:attributes].each do |attribute|
             current_val = send(attribute)
             if (force && !not_force_for.include?(attribute)) || current_val.blank?
-              send("#{attribute}=", parent.send(attribute))
+              if use_update
+                update_attributes(attribute => parent.send(attribute))
+              else
+                send("#{attribute}=", parent.send(attribute))
+              end
             end
           end
         end

spec/acts_as_inheritable_spec.rb

@@ -53,6 +53,17 @@ class Person < ActiveRecord::Base
         end
       end
     end
+    context 'when `use_update` is set to true' do
+      let(:person){ create(:person, :with_parent, favorite_color: nil, last_name: nil, soccer_team: nil) }
+      let!(:person_parent) { person.parent }
+      it 'inherits values from his parent even if those attributes have a value' do
+        person.inherit_attributes false, [], true
+        person.reload
+        expect(person.favorite_color).to eq person_parent.favorite_color
+        expect(person.last_name).to eq person_parent.last_name
+        expect(person.soccer_team).to eq person_parent.soccer_team
+      end
+    end
   end
 
   describe '#inherit_relations' do