I believe what you are asking for can be achieved with ActiveSupport::Callbacks. Have a look at set_callback and skip_callback.
In order to “force callbacks to get called even if you made no changes to the record”, you need to register the callback to some event e.g. save, validate etc..
set_callback :save, :before, :my_before_save_callback
To skip the before_save callback, you would do:
Survey.skip_callback(:save, :before, :calculate_average).
Please reference the linked ActiveSupport::Callbacks on other supported options such as conditions and blocks to set_callback and skip_callback.